Common use of Introductory Clause in Contracts

Introductory. MEI Pharma, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaSignature Resorts, Inc., a Delaware Maryland ------------ corporation (the “"Company”"), proposes to issue and sell 1,600,000 shares of its authorized but unissued common stock, $.01 par value (the "Common Stock"), and the several stockholders of the Company listed in Schedule A annexed hereto (the "Selling Stockholders"), propose to sell 2,400,000 shares of the Company's issued and outstanding Common Stock to the several underwriters named in Schedule A B annexed hereto (the “"Underwriters”) an "), for whom you are acting as representatives (the "Representatives"). Said aggregate of 28,125,000 4,000,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are herein called the “"Firm Common Shares.” " In addition, the Company has granted and the Selling Stockholders propose to grant to the Underwriters an option to purchase up to an 240,000 and 360,000 additional 4,218,750 Shares shares, respectively (the "Option Common Shares") as provided in Section 25 hereof. The additional 4,218,750 Option Shares to be sold by of the Company pursuant to such option respective Selling Shareholders are collectively called the “Optional Shares.” set forth on Schedule A annexed hereto. The Firm Common Shares and, if and to the extent such option is exercised, the Optional Option Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection " Concurrently with the offering and sale of the Offered Common Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, Company proposes to issue and sell an aggregate of $100,000,000 principal amount of its ____% Convertible Subordinated Notes Due 2007 (the "Notes"). You have advised the Company and the term “Underwriters” shall mean either Selling Stockholders that the singular Underwriters propose to make a public offering of their respective portions of the Common Shares on the effective date of the Registration Statement hereinafter referred to, or the plural, as the context requiressoon thereafter as in your judgment is advisable. The Company has prepared and filed the Selling Stockholders hereby confirm their respective agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.SINA Corporation, a Delaware Cayman Islands corporation (the “Company”), proposes proposes, subject to the terms and conditions stated herein, to issue and sell to the several underwriters initial purchasers named in Schedule A hereto (the “UnderwritersPurchasers”) U.S.$80,000,000 aggregate principal amount of its Zero Coupon Convertible Subordinated Notes due 2023 (the “Firm Securities”) and also proposes to grant to the Purchasers an option, exercisable from time to time by Credit Suisse First Boston LLC to purchase an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares U.S.$20,000,000 principal amount (“Optional Securities”) of its Zero Coupon Convertible Subordinated Notes due 2023, to be issued under an indenture, which is expected to be entered into on July 7, 2003 (the “Indenture”), between the Company and The Bank of New York, as provided in Section 2Trustee. The additional 4,218,750 Shares Firm Securities and the Optional Securities which the Purchasers may elect to be sold by the Company purchase pursuant to such option Section 3 hereof are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are herein collectively called the “Offered SharesSecurities”. The United States Securities Act of 1933, as amended, is herein referred to as the “Securities Act.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale The holders of the Offered Shares. To Securities will be entitled to the extent there are no additional underwriters listed on Schedule A, benefits of a Registration Rights Agreement of even date herewith among the term “Representatives” as used herein shall mean you, as Underwriters, Company and the term Purchasers (the “Underwriters” shall mean either Registration Rights Agreement”), pursuant to which the singular or the plural, as the context requires. The Company has prepared and filed agrees to file a registration statement with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (registering the “Base Prospectus”) to be used in connection with the public offering and sale resale of the Offered Securities and the Underlying Shares. Such registration statement, as amendedhereinafter defined, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the . The Company pursuant to Rule 462(b) under the Securities Act in connection hereby agrees with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseseveral Purchasers as follows:

Introductory. MEI Pharma, Inc.First Potomac Realty Trust, a Delaware corporation Maryland real estate investment trust (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares 3,000,000 of its common stockshares (the “Firm Shares”) of beneficial interest, par value $0.00000002 .001 per share (the “Common Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 450,000 Common Shares (the “Option Shares”), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇KeyBanc Capital Markets, ▇▇▇▇▇▇▇▇ & Company, Incorporated a division of McDonald Investments Inc. (“StifelKCM”) and ▇▇▇▇▇ Fargo Securities), LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To The Company is the extent there are no additional underwriters listed on Schedule Asole general partner of First Potomac Realty Investment Limited Partnership (the “Operating Partnership”), the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, a Delaware limited partnership that serves as the context requiresCompany’s primary operating partnership subsidiary. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or a registration statement on Form S-3 (File No. 333-120821), which contains a form of prospectus to be used in connection with the public offering and sale of the Shares. Such registration statement, herein referred to as the “Registration Statement,” shall be deemed to include all information omitted therefrom in reliance upon Rule 430A and all information incorporated by reference therein. The form of final prospectus first filed by the Company with the Commission pursuant to Rule 424(b) is herein referred to as the “Prospectus.” Each preliminary prospectus included in the Registration Statement is herein referred to as a “Preliminary Prospectus.” Any reference herein to any Preliminary Prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A supplements or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement amendments thereto filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale Commission as of the Offered Shares is called date of such Preliminary Prospectus or Prospectus, as the “Rule 462(b) Registration Statement,” case may be, and from and any supplements or amendments thereto, filed with the Commission after the date and time of the filing of any such the Prospectus under Rule 462(b424(b) Registration Statement or 430A, and prior to the term “Registration Statement” shall include termination of the Rule 462(b) Registration Statementoffering of the Shares by the Underwriters. The preliminary prospectus supplement dated December 16, 2019 describing Each of the Offered Shares Company and the offering thereof (the “Preliminary Prospectus Supplement”), together Operating Partnership hereby confirms its agreements with the BaseUnderwriters as follows:

Introductory. MEI PharmaKulicke and ▇▇▇▇▇ Industries, Inc., a Delaware Pennsylvania corporation (the “"Company”"), proposes to issue and sell 2,500,000 shares of its authorized but unissued Common Stock (the "Common Stock"), and C. ▇▇▇▇▇ ▇▇▇▇▇▇▇ and his spouse (collectively, the "Selling Shareholder") propose to sell 100,000 shares of the Company's issued and outstanding Common Stock, to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an "), for whom you are acting as Representatives. Said aggregate of 28,125,000 2,600,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are herein called the “"Firm Common Shares.” " In addition, the Company has granted and the Selling Shareholder propose to grant to the Underwriters an option to purchase up to an aggregate of 390,000 additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively referred to as the "Common Shares." The Common Shares to be sold by the Company are herein called the “Offered "Company Shares" and the Common Shares to be sold by the Selling Shareholder are herein called the "Selling Shareholder Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Shareholder that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacity, Common Shares on the “Representatives”) in connection with the offering and sale effective date of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aregistration statement hereinafter referred to, the term “Representatives” or as used herein shall mean you, soon thereafter as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresin your judgment is advisable. The Company has prepared and filed the Selling Shareholder hereby confirm their respective agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI Pharma, (a) Talos Energy Inc., a Delaware corporation (the “Company”), proposes agrees, subject to the terms and conditions stated in this agreement (this “Agreement”), to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) ), for whom you are acting as Representatives, an aggregate of 28,125,000 30,000,000 shares (the “Firm Securities”) of its common stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”), of the Company. The 28,125,000 Shares Company also agrees to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted sell to the Underwriters Underwriters, at the option of the Underwriters, an option to purchase up to an aggregate of not more than 4,500,000 additional 4,218,750 Shares shares (“Optional Securities”) of the Company’s Common Stock, as provided in Section 2set forth below. The additional 4,218,750 Shares to be sold by Firm Securities and the Company pursuant to such option Optional Securities are herein collectively called the “Optional SharesSecurities.” ” (b) The Firm Shares andSecurities are being issued to fund, if and to consummated, a portion of the extent such option is exercised, cash purchase price of the Optional Shares are collectively called acquisition (the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Acquisition”) of QuarterNorth Energy Inc. (“StifelQuarterNorth”) and ▇▇▇▇▇ Fargo Securitiesits wholly owned subsidiaries, LLC pursuant to that certain Agreement and Plan of Merger (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection together with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectivelysupplemented or otherwise modified, the “Securities ActAcquisition Agreement”), including all documents incorporated or deemed dated January 13, 2024, by and among the Company, QuarterNorth Energy Inc., Compass Star Merger Sub Inc. and Equityholders’ Representative, and to be incorporated by reference therein pay fees and any information deemed expenses related to be a part thereof at the time foregoing. These uses of effectiveness pursuant to Rule 430A or 430B under the proceeds of the issuance of the Securities Act, is are herein collectively called the “Registration StatementTransactions.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaEvolus, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 3,000,000 shares (the “Primary Firm Shares”) of its common stock, par value $0.00000002 0.00001 per share (the “Shares”) and Alphaeon Corporation, a Delaware corporation (the “Selling Stockholder”), proposes to sell to the Underwriters an aggregate of 1,000,000 Shares (the “Secondary Offered Shares”). The 28,125,000 Primary Firm Shares to be sold by the Company and the Secondary Offered Shares to be sold by the Selling Stockholder are collectively called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 600,000 Shares (the “Primary Optional Shares”) as provided in Section 2. The additional 4,218,750 600,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Primary Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Primary Offered Shares.” The Primary Offered Shares and the Secondary Offered Shares are collectively referred to as the “Offered Shares.” Cantor ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Co. (“StifelCantor”) and ▇▇▇▇▇ Fargo Securities, Mizuho Securities USA LLC (“▇▇▇▇▇ FargoMizuho”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean youthe Representatives, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Crescent Energy OpCo LLC, a Delaware corporation limited liability company (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A repurchase (the “UnderwritersRepurchase”) an aggregate of 28,125,000 shares of its common stockfrom Independence Energy Aggregator L.P., par value $0.00000002 per share a Delaware limited partnership (the “SharesHolder”), units representing membership interests in the Company (“Units”), on the terms and subject to the conditions set forth herein. The Company and the Holder agree that the Repurchase contemplated hereby is being effected in lieu of the exercise by the Holder of its redemption right described in Section 3.6(a)(i) of the Amended and Restated Limited Liability Company Agreement of the Company, dated as of December 7, 2021 (the “LLC Agreement”), and the exercise by the Company of its cash election right described in Section 3.6(a)(iii) of the LLC Agreement in connection with the offering contemplated by the Underwriting Agreement (as defined below). The 28,125,000 Shares parties hereto (including Crescent (as defined below)) further approve and consent to be sold by the transactions contemplated hereby. Concurrently with this Repurchase Agreement (this “Agreement”), Crescent Energy Company, a Delaware corporation and the managing member of the Company are called (“Crescent”), is entering into an underwriting agreement, dated as of the date hereof (the “Firm Shares.” In additionUnderwriting Agreement”), with the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) Holder and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act and Evercore Group L.L.C., as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission therein (the “CommissionUnderwriters”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus pursuant to which the Holder has agreed to sell to the several Underwriters 12,000,000 shares (the “Base ProspectusFirm Shares”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statementCrescent’s Class A common stock, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof par value $0.0001 per share (the “Preliminary Prospectus SupplementClass A Common Stock”). The Holder has also agreed to sell to the several Underwriters, at the option of the Underwriters, an aggregate of not more than 1,800,000 additional shares (the “Optional Shares” and, together with the BaseFirm Shares, the “Offered Shares”) of Class A Common Stock. The Company hereby confirms its agreements with the Holder as follows:

Introductory. MEI PharmaPermian Resources Operating, Inc.LLC, a Delaware corporation limited liability company (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A repurchase (the “UnderwritersRepurchase”) an aggregate from each of 28,125,000 shares NGP XI US Holdings, L.P. (“NGP XI”), NGP Pearl Holdings II, L.L.C. (“NGP Pearl”) and Luxe Energy, LLC (“Luxe” and, collectively with NGP XI and NGP Pearl, the “Holders”), common units representing limited liability company interests in the Company (“Units”), on the terms and subject to the conditions set forth herein. The Company and the Holders agree that the Repurchase contemplated hereby is being effected in lieu of its common stockthe exercise by the Holders of their redemption rights described in Section 11.01 of the Sixth Amended and Restated Limited Liability Company Agreement of the Company, par value $0.00000002 per share dated as of September 1, 2022 (the “SharesLLC Agreement”), and the exercise by the Company of its right of Cash Settlement (as defined in the LLC Agreement) described in Section 11.01 of the LLC Agreement in connection with the offering contemplated by the Underwriting Agreement (as defined below). The 28,125,000 Shares parties hereto (including the Corporation (as defined below)) further approve and consent to be sold by the transactions contemplated hereby. Concurrently with this Repurchase Agreement (this “Agreement”), Permian Resources Corporation, a Delaware corporation and the managing member of the Company are called (the “Firm Shares.” In additionCorporation”), is entering into an underwriting agreement, dated as of the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called date hereof (the “Optional SharesUnderwriting Agreement”), with the Holders and ▇.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇. ▇▇▇▇▇▇ & CompanySecurities LLC, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo BofA Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act Inc. and Truist Securities, Inc., as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission therein (the “CommissionUnderwriters”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus pursuant to which the Holders have agreed to sell to the several Underwriters 21,450,000 shares (the “Base ProspectusFirm Shares”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statementCorporation’s Class A Common Stock, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof par value $0.0001 per share (the “Preliminary Prospectus SupplementClass A Common Stock”). The Holders also agreed to sell to the several Underwriters, at the option of the Underwriters, an aggregate of not more than 3,217,500 additional shares (the “Optional Shares” and, together with the BaseFirm Shares, the “Offered Shares”) of Class A Common Stock. The Company hereby confirms its agreements with the Holders as follows:

Introductory. MEI Pharma, A▇▇▇▇-▇▇▇▇▇▇▇▇ Energy Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 2,500,000 shares (the “Firm Shares”) of its common stockCommon Stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 375,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Shares, are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have . RBC Capital Markets Corporation has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To As more fully described in the extent there are no additional underwriters listed on Schedule ARegistration Statement (as defined below), the term Company has agreed to purchase all of the outstanding capital stock of DLS Drilling, Logistics & Services Corporation (“Representatives” as used herein shall mean youDLS”), pursuant to a stock purchase agreement dated April 27, 2006. The acquisition by the Company of all of the outstanding capital stock of DLS, as Underwritersdescribed in the Registration Statement, is referred to herein as the “Acquisition.” With respect to the representations, warranties and agreements made by the Company in this Agreement concerning its subsidiaries, such representations, warranties and agreements shall be deemed to include DLS. In connection with the Acquisition, the Company will (i) offer and sell the Securities contemplated by this Agreement; (ii) offer and sell the Notes pursuant to a purchase agreement dated , 2006 between the Company, the guarantors and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared initial purchasers named therein; and filed with the Securities and Exchange Commission (iii) enter into an amendment of its $25.0 million senior secured credit facility (the “CommissionBank Credit Facility”). These transactions (but not including the offering of the Securities contemplated by this Agreement and the Registration Statement) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (are collectively referred to herein as the “Base ProspectusTransactions.”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaThe Company has entered into a forward stock purchase transaction with Bank of America, Inc., a Delaware corporation N.A. (the “CompanyForward Purchaser”)) as set forth in a separate letter agreement dated the date hereof, proposes to issue and sell to the several underwriters named in Schedule a copy of which is attached hereto as Exhibit A (the “UnderwritersInitial Confirmation”). The Company may also enter into additional forward stock purchase transactions with the Forward Purchaser on substantially similar terms (each, a “Subsequent Confirmation” and, together with the Initial Confirmation, the “Confirmations”). The Company has also entered into a distribution agency agreement (the “Additional Distribution Agency Agreement”), dated the date hereof, with Deutsche Bank Securities Inc. (the “Additional Manager”) and a forward stock purchase transaction with an aggregate affiliate of 28,125,000 the Additional Manager and the Company may enter into additional forward stock purchase transactions with an affiliate of the Additional Manager. Subject to the terms and conditions herein and therein, under the Confirmation and, if applicable, the Subsequent Confirmations, the Company will deliver to the Forward Purchaser, or an affiliate thereof (including the Manager), up to the number of shares of its the Company’s common stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to , as may be sold by in accordance with the Company are called the “Firm Shares.” terms of this Agreement. In additionconnection therewith, the Company has granted to and the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by Forward Purchaser understand that the Company pursuant to such option are collectively called Forward Purchaser, through the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean youManager, as Underwriterssales agent, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission will effect sales of shares of Common Stock having an aggregate offering price not in excess of $300,000,000 (the “CommissionShares”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus the terms set forth in Section 2 of this Distribution Agency Agreement (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActAgreement”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Medialink Worldwide Incorporated, a Delaware corporation (the “"Company”"), proposes to issue and sell sell, pursuant to the terms of this Agreement, to the several underwriters Underwriters named in Schedule A hereto (the “"Underwriters”" which term also shall include any underwriter substituted as hereinafter provided in Section 11) an aggregate of 28,125,000 2,000,000 shares of its common stockCommon Stock, par value $0.00000002 .01 per share (the “Shares”)"Common Stock") of the Company. The 28,125,000 Shares aggregate of 2,000,000 shares so proposed to be sold by are hereinafter referred to as the Company are called "Firm Stock." The selling stockholders named in Schedule B hereto (the “Firm Shares.” In addition, the Company has granted "Selling Stockholders") also propose to sell severally to the Underwriters Underwriters, on a pro rata basis, at the option of the Underwriters, an option to purchase up to an additional 4,218,750 Shares aggregate of not more than 300,000 shares of Common Stock as provided in Section 23 of this Agreement. The additional 4,218,750 Shares aggregate of 300,000 shares so proposed to be sold by is herein called the Company pursuant to such option "Optional Stock." The Firm Stock and the Optional Stock are collectively called referred to herein as the “Optional Shares"Stock.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” " ▇▇▇▇ ▇▇▇▇▇▇, ▇ ▇▇▇▇▇▇▇▇ & CompanyInc. and Wheat, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo First Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act Inc. are acting as representatives of the several Underwriters (and in such capacitycapacity are hereinafter referred to as the "Representatives." Before the purchase and public offering of the Stock by the several Underwriters, the “Company and the Representatives”) in connection with the offering and sale , acting on behalf of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as several Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, enter into an agreement substantially in the form in which it became effective under of Exhibit A hereto (the Securities Act "Pricing Agreement"). The offering of 1933the Stock will be governed by this Agreement, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BasePricing Agreement.

Introductory. MEI PharmaEpizyme, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 304,348 shares of its common stockSeries A Convertible Preferred Stock, par value $0.00000002 0.0001 per share (the “Preferred Shares”). The 28,125,000 304,348 Preferred Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 45,652 Preferred Shares as provided in Section 2. The additional 4,218,750 45,652 Preferred Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” The shares of common stock, par value $0.0001 per share of the Company (the “Common Shares”) issuable upon conversion of the Offered Shares are hereinafter referred to as the “Conversion Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated LLC (“StifelJefferies”), Citigroup Global Markets Inc. (“Citi”) and ▇▇▇▇▇ Fargo Securitiesand Company, LLC (“▇▇▇▇▇ FargoCowen”) have agreed to act as representatives Representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission Underwriters are also entering into that certain Underwriting Agreement, of even date herewith (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActCommon Shares Underwriting Agreement”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by which the Company will issue and sell an aggregate of 10,000,000 Common Shares, plus up to an additional 1,500,000 Common Shares pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters’ option to purchase additional shares.

Introductory. MEI Pharma, Inc.First Potomac Realty Trust, a Delaware corporation Maryland real estate investment trust (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares 5,500,000 of its common stockshares (the “Firm Shares”) of beneficial interest, par value $0.00000002 .001 per share (the “Common Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 825,000 Common Shares (the “Option Shares”), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated KeyBanc Capital Markets Inc. (“StifelKCM”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) ), have agreed to act as the representatives of the several Underwriters (in such capacity, collectively, the “Representatives”) in connection with the offering and sale of the Offered Shares. To The Company is the extent there are no additional underwriters listed on Schedule Asole general partner of First Potomac Realty Investment Limited Partnership, a Delaware limited partnership (the term “Representatives” as used herein shall mean youOperating Partnership”), as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, that serves as the context requiresCompany’s primary operating partnership subsidiary. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or on April 16, 2007 a registration statement on Form S-3, which was subsequently amended on August 19, 2008 and August 22, 2008 (File No. 333-142147), which contains a form of prospectus to be used in connection with the public offering and sale of the Shares (the “Base Prospectus”). Such registration statement, herein referred to as the “Registration Statement,” shall be deemed to include all information omitted therefrom in reliance upon Rules 430A or 430B under the Securities Act and all information incorporated by reference therein. The form of final prospectus supplement to the Base Prospectus relating to the Shares and the offering thereof filed by the Company with the Commission pursuant to Rule 424(b) under the Securities Act and first used by the Underwriters to confirm sales of the Shares is herein referred to as the “Prospectus.” The Base Prospectus, as supplemented by the preliminary prospectus (including any preliminary prospectus supplement) relating to the Shares and the offering thereof most recently filed by the Company with the Commission pursuant to Rule 424(b) and used prior to the date hereof is herein referred to as a “Preliminary Prospectus.” Any reference herein to the Registration Statement, any Preliminary Prospectus or the Prospectus or to any amendment or supplement to any of the foregoing documents shall be deemed to refer to and include any documents incorporated by reference therein and any information deemed to be a part thereof at supplements or amendments thereto, filed with the time Commission after the date of effectiveness pursuant to filing of the Prospectus under Rule 430A or 430B 424(b) under the Securities Act, is called and prior to the “Registration Statement.” Any registration statement filed termination of the offering of the Shares by the Underwriters. Each of the Company pursuant to Rule 462(b) under and the Securities Act in connection Operating Partnership hereby confirms its agreements with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI PharmaLamalie Associates, Inc., a Delaware Florida corporation (the “Company”"COMPANY"), proposes to issue and sell an aggregate of 2,089,540 shares of common stock, $0.01 par value per share (the "COMMON STOCK") and the several stockholders of the Company identified in Schedule I annexed hereto (the "SELLING STOCKHOLDERS") propose to sell an aggregate of 910,460 shares of Common Stock (such 3,000,000 shares, collectively, the "FIRM SHARES") to the several underwriters named identified in Schedule A II annexed hereto (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock"UNDERWRITERS"), par value $0.00000002 per share (the “Shares”)who are acting severally and not jointly. The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted agreed to grant to the Underwriters an option to purchase up to an 450,000 additional 4,218,750 Shares shares of Common Stock (the "OPTIONAL SHARES") as provided in Section 26 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are hereinafter collectively called referred to as the “Offered Shares"SHARES.” ▇▇▇▇▇▇" All references herein to "the Company" are to Lamalie Associates, ▇▇▇▇▇▇▇▇ & CompanyInc., Incorporated (“Stifel”) a Florida corporation, and, for all periods prior to June 3, 1997 and ▇▇▇▇▇ Fargo Securitieswhen --------------------- * Plus an option to acquire up to 450,000 additional shares of Common Stock from the Company to cover over-allotments. the context otherwise requires, LLC (“▇▇▇▇▇ Fargo”) have agreed to act its predecessor Lamalie Associates, Inc., a Delaware corporation. You, as representatives of the several Underwriters (in such capacitythe "REPRESENTATIVES"), have advised the “Representatives”) in connection with Company and the Selling Stockholders that the Underwriters propose to make a public offering and sale of their respective portions of the Offered Shares. To Shares as soon hereafter as in your judgment is advisable and that the extent there are no additional underwriters listed on Schedule A, public offering price of the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresShares initially will be [$______] per share. The Company has prepared and filed the Selling Stockholders hereby confirm their respective agreements with the Securities Underwriters and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, each other as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaKeynote Systems, Inc., a Delaware California corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A (the “"Underwriters”") an aggregate of 28,125,000 1,000,000 shares of its common stockCommon ---------- Stock, par value $0.00000002 0.001 per share (the “"Common Shares”"); and the shareholders of the Company identified in Schedule B as "Principal Selling Shareholders" (the ---------- "Principal Selling Shareholders") and the shareholders of the Company identified in Schedule B as "Other Selling Shareholders" (the "Other Selling Shareholders" ---------- and, collectively, together with the Principal Selling Shareholders, the "Selling Shareholders") propose to sell to the Underwriters an aggregate of Common Shares. The 28,125,000 1,000,000 Common Shares to be sold by the Company and the 3,750,000 Common Shares to be sold by the Selling Shareholders are collectively called the “"Firm Shares.” ". In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 712,500 Common Shares (the "Option Shares"), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Option Shares, are collectively called the “Offered "Shares.” ". FleetBoston ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ Inc., ▇▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo SecuritiesLLC, LLC (“▇▇▇▇ ▇▇▇▇▇▇▇▇ Fargo”) Incorporated, and SoundView Technology Group, Inc. have agreed to act as representatives of the several Underwriters (in such capacity, the “"Representatives”") in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “"Commission”") a shelf registration statement on Form S-3, S-1 (File No. 333-21764594651), including which contains a base prospectus (the “Base Prospectus”) form of prospectus, subject to completion, to be used in connection with the public offering and sale of the Offered Shares. Each such prospectus, subject to completion, used in connection with such public offering is called a "preliminary prospectus." Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, 1933 and the rules and regulations promulgated thereunder (collectively, the “"Securities Act”"), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B Rule 434 under the Securities Act, is called the “"Registration Statement.” ". Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “"Rule 462(b) Registration Statement,” ", and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “"Registration Statement” " shall include the Rule 462(b) Registration Statement. The Such prospectus, in the form first used by the Underwriters to confirm sales of the Shares, is called the "Prospectus." All references in this Agreement to the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus supplement dated December 16prospectus, 2019 describing the Offered Shares and Prospectus or the offering Term Sheet, or any amendments or supplements to any of the foregoing, shall include any copy thereof (the “Preliminary Prospectus Supplement”), together filed with the BaseCommission pursuant to its Electronic Data Gathering, Analysis and Retrieval System ("▇▇▇▇▇"). The Company and each of the Selling Shareholders hereby confirms their agreements with the Underwriters as follows:

Introductory. MEI PharmaxG Technology, Inc., a corporation organized under the laws of the State of Delaware corporation (the “Company”), proposes proposes, pursuant to issue the terms of this Placement Agency Agreement (this “Agreement”) and the subscription agreements in substantially the form of Exhibit A attached hereto (the “Subscription Agreements”) entered into with the purchasers identified therein (each a “Purchaser” and collectively, the “Purchasers”), to sell to the several underwriters named Purchasers an aggregate of [__] Units (the “Units”), each Unit consisting of (A) one share of Series B Convertible Preferred Stock, par value $0.00001 per share (the “Preferred Stock”), such Preferred Stock to have the relative rights, preferences, limitations and other designations set forth in Schedule the Certificate of Designations, Preferences and Rights attached hereto in Exhibit A (the “UnderwritersCertificate of Designations”), and (B) 0.5 Warrants (the “Warrants”) an aggregate to purchase one share (the “Warrant Shares”) of 28,125,000 shares of its common stock, par value $0.00000002 0.00001 per share (the “Common Stock”) in the form attached hereto as Exhibit B. The Common Stock issuable upon the conversion of the Preferred Stock is herein referred to as the “Conversion Shares”. The Preferred Stock and Warrants are collectively referred to herein as the “Securities”. The Units are more fully described in the Prospectus (as defined below). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇hereby confirms its agreement with ▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo SecuritiesCapital Partners, LLC (the “▇▇▇▇▇ FargoPlacement Agent”) have agreed to act as representatives of the several Underwriters (sole placement agent in such capacity, the “Representatives”) in connection accordance with the offering terms and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” conditions hereof as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementset forth below.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Orchard Supply Hardware Stores Corporation, a ------------ Delaware corporation (the “"Company”"), proposes to issue and sell 500,000 shares of its authorized but unissued Common Stock (the "Common Stock") and the stockholder of the Company named in Schedule B annexed hereto (the "Selling Stockholder") proposes to sell an aggregate of 2,000,000 shares of the Company's issued and outstanding Common Stock to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an "), for whom you are acting as Representatives. Said aggregate of 28,125,000 2,500,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are herein called the “"Firm Common Shares.” " In addition, the Company has granted Selling Stockholder proposes to grant to the Underwriters an option to purchase up to an 375,000 additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Stockholder that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacity, Common Shares on the “Representatives”) in connection with the offering and sale effective date of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aregistration statement hereinafter referred to, the term “Representatives” or as used herein shall mean you, soon thereafter as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresin your judgment is advisable. The Company has prepared and filed the Selling Stockholder hereby confirm their respective agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.Wave Life Sciences Ltd. (Company Registration Number: 201218209G), a Delaware corporation company incorporated under the laws of the Republic of Singapore (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) (i) an aggregate of 28,125,000 shares 15,789,475 of its common stockordinary shares, no par value $0.00000002 per share (the “Shares”) and (ii) pre-funded warrants, substantially in the form of Exhibit C hereto, to purchase up to an aggregate of 2,631,578 Shares (the “Pre-Funded Warrants”). The 28,125,000 15,789,475 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 2,763,157 Shares as provided in Section 2. The additional 4,218,750 2,763,157 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” The Shares issuable upon exercise of the Pre-Funded Warrants are referred to herein as the “Warrant Shares.” The Offered Shares, the Pre-Funded Warrants and the Warrant Shares are collectively referred to herein as the “Offered Securities.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & CompanyLLC, Incorporated (“Stifel”) Leerink Partners LLC and ▇▇▇▇▇ Fargo BofA Securities, LLC (“▇▇▇▇▇ Fargo”) Inc. have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a an “automatic shelf registration statement statement,” as defined under Rule 405 under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), on Form S-3S-3ASR, File No. 333-217645283122, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered SharesSecurities. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basepromulgated

Introductory. MEI PharmaU.S. Restaurant Properties, Inc., a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 2,575,000 shares of its common stockCommon Stock, par value $0.00000002 .001 per share (the “SharesCommon Stock”); and the stockholders of the Company named in Schedule B (collectively, the “Selling Stockholders”) severally propose to sell to the Underwriters an aggregate of 1,500,000 shares of Common Stock. The 28,125,000 Shares 2,575,000 shares of Common Stock to be sold by the Company and the 1,500,000 shares of Common Stock to be sold by the Selling Stockholders are collectively called the “Firm Common Shares.” In addition, the Company has Selling Stockholders have granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 611,250 shares of Common Stock, each Selling Stockholder selling up to the amount set forth opposite such Selling Stockholder’s name in Schedule B, all as provided in Section 2. The additional 4,218,750 Shares 611,250 shares to be sold by the Company Selling Stockholders pursuant to such option options are collectively called the “Optional Common Shares.” The Firm Common Shares and, if and to the extent such option is options are exercised, the Optional Common Shares are collectively called the “Offered Common Shares.” Banc of America Securities LLC (“BAS”), ▇▇▇▇▇▇, ▇▇▇ ▇▇▇▇▇▇ & Company, Incorporated Inc. (“StifelMK”) ), and ▇▇▇▇▇ Fargo Southwest Securities, LLC Inc. (“▇▇▇▇▇ FargoSouthwest”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Common Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement statements on Form S-3, S-3 (File No. 333-21764566371 and File No. 333-108054), including a base prospectus (the “Base Prospectus”) which contain prospectuses dated July 12, 1999, and October 1, 2003, respectively, to be used in connection with the public offering and sale of the Offered Common Shares. Such registration statementstatements, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became they were declared effective by the Commission under the Securities Act of 1933, as amended, 1933 and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated by reference or deemed to be incorporated by reference therein and therein, including any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B Rule 434 under the Securities Act or the Securities Exchange Act of 1934 and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is are collectively called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary A prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”) setting forth the terms of the offering, the plan of distribution of the Common Shares and additional information concerning the Company and its business has been or will be so prepared and will be so prepared and filed pursuant to Rule 424(b) of the Securities Act on or before the second business day after the date hereof (or such earlier time as may be required by the Securities Act). The July 12, 1999, prospectus and the October 1, 2003, prospectus together with the Prospectus Supplement, in the form first used by the Underwriters to confirm sales of the Common Shares, are called the “Prospectus”; provided, however, if the Company has, with the consent of BAS, elected to rely upon Rule 434 under the Securities Act, the term “Prospectus” shall mean the Company’s “prospectus subject to completion” (as defined in Rule 434(g) under the Securities Act) last provided to the Underwriters by the Company (each, a “preliminary prospectus”) dated October 1, 2003 (such preliminary prospectus is called the “Rule 434 preliminary prospectus”), together with the Baseapplicable term sheet (the “Term Sheet”) prepared and filed by the Company with the Commission under Rules 434 and 424(b) under the Securities Act and all references in this Agreement to the date of the Prospectus shall mean the date of the Term Sheet. Notwithstanding the foregoing, if any revised prospectus shall be provided to the Underwriters by the Company for use in connection with the offering of the Shares that differs from the prospectus referred to in the immediately preceding sentence (whether or not such revised prospectus is required to be field with the Commission pursuant to Rule 424(b) under the Securities Act), the term “Prospectus” shall refer to such revised prospectus from and after the time it is first provided to the Underwriters for such use. All references in this Agreement to (i) the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus, the Prospectus or the Term Sheet, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System (“▇▇▇▇▇”). All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement or the Prospectus (and all other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which are or are deemed to be incorporated by reference in the Registration Statement or the Prospectus, as the case may be; and all references in this Agreement to amendments or supplements to the Registration Statement or the Prospectus shall be deemed to mean and include the filing of any document under the Exchange Act which is or is deemed to be incorporated by reference in the Registration Statement or the Prospectus, as the case may be.

Introductory. MEI Pharma, Inc.Nassda Corporation, a Delaware corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A (the “---------- "Underwriters”") an aggregate of 28,125,000 5,000,000 shares (the "Firm Shares") of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “"Common Shares”"). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 750,000 Common Shares (the "Option Shares") as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered "Shares.” ". ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company▇▇▇▇▇▇▇▇, Incorporated Inc. (“Stifel”) and "▇▇▇▇▇▇▇▇▇ Fargo Securities▇▇▇▇▇▇▇▇"), LLC (“▇▇ ▇▇▇▇▇ Fargo”) Securities Corporation and UBS Warburg LLC have agreed to act as representatives Representatives of the several Underwriters (in such capacity, the “"Representatives”") in connection with the offering and sale of the Offered Shares. To As a part of this offering contemplated by this Agreement, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ has agreed to reserve out of the extent there are no additional underwriters listed Shares set forth opposite its name on the Schedule AII to this Agreement, up to 250,000 shares, for sale to parties associated with the term “Representatives” as used herein shall mean youCompany (collectively, "Participants"), as Underwriters, and set forth in the term “Underwriters” shall mean either Prospectus under the singular or heading "Underwriting" (the plural, "Directed Share Program"). The Shares to be sold by ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ pursuant to the Directed Share Program (the "Directed Shares") will be sold by ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ pursuant to this Agreement at the public offering price. Any Directed Shares not orally confirmed for purchase by any Participants as of 7:00 A.M. California time on the context requiresfirst day trading of the Shares commences will be offered to the public by ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ as set forth in the Prospectus. The Company has prepared and filed with the Securities and Exchange Commission (the “"Commission”") a shelf registration statement on Form S-3, S-1 (File No. 333-21764568934), including which contains a base prospectus (the “Base Prospectus”) form of prospectus, subject to completion, to be used in connection with the public offering and sale of the Offered Shares. Each such prospectus, subject to completion, used in connection with such public offering is called a "preliminary prospectus". Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, 1933 and the rules and regulations promulgated thereunder (collectively, the “"Securities Act”"), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “"Registration Statement.” ". Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “"Rule 462(b) Registration Statement,” ", and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “"Registration Statement” " shall include the Rule 462(b) Registration Statement. The Such prospectus, in the form first used by the Underwriters to confirm sales of the Shares, is called the "Prospectus". All references in this Agreement to the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus supplement dated December 16prospectus, 2019 describing the Offered Shares and Prospectus or any amendments or supplements to any of the offering foregoing, shall include any copy thereof (the “Preliminary Prospectus Supplement”), together filed with the BaseCommission pursuant to its Electronic Data Gathering, Analysis and Retrieval System ("▇▇▇▇▇"). The Company hereby confirms its agreements with the Underwriters as follows:

Introductory. MEI PharmaJinkoSolar Holding Co., Inc.Ltd., a Delaware corporation an exempted company incorporated under the laws of the Cayman Islands (the “Company”), proposes to issue and sell to agrees with the several underwriters Underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company for whom you are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act acting as representatives of the several Underwriters (you, in such capacity, the “Representatives”) in connection with to issue and sell to the offering several Underwriters up to 3,800,000 American Depositary Shares (“ADSs” and sale each an “ADS”) each representing four ordinary shares, par value US$0.00002 per share, of the Offered Company (“Ordinary Shares. To ”), and also proposes to issue and sell to the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and at the term “option of the Underwriters” shall mean either the singular or the plural, an aggregate of not more than 570,000 additional ADSs as the context requiresset forth below. The Company has prepared and filed with the Securities and Exchange Commission aforesaid 3,800,000 ADSs (the “CommissionFirm Securities”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus and all or any part of the 570,000 ADSs subject to the option described below (the “Base ProspectusOptional Securities”) are hereinafter collectively called the “Offered Securities”. We understand the ADSs are to be used in connection with the public offering and sale of the Offered Shares. Such registration statementissued pursuant to a deposit agreement dated February 9, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, 2010 and the rules and regulations promulgated thereunder amendment to the deposit agreement dated as of May 13, 2010 (collectively, the “Securities ActDeposit Agreement”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at among the time of effectiveness pursuant to Rule 430A or 430B under the Securities ActCompany, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16JPMorgan Chase Bank, 2019 describing the Offered Shares and the offering thereof N.A., as depositary (the “Preliminary Prospectus SupplementDepositary”), together with and holders from time to time of the BaseAmerican Depositary Receipts (the “ADRs”) issued by the Depositary and evidencing the ADSs. This agreement (the “Agreement”) and the Offered Securities, as each may be amended or supplemented from time to time, are hereinafter collectively referred to as the “Transaction Documents”. Capitalized terms not otherwise defined herein have the meanings ascribed to them in the Final Prospectus.

Introductory. MEI PharmaPraxis Precision Medicines, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 55,150,000 shares (the “Firm Shares”) of its common stock, par value $0.00000002 0.0001 per share (the “Common Stock”) and (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 7,050,000 shares of Common Stock (the “Warrant Shares”). ) at an exercise price of $0.0001 per share in the form attached hereto as Exhibit A. The 28,125,000 55,150,000 Firm Shares and 7,050,000 Pre-Funded Warrants to be sold by the Company are called the “Firm SharesSecurities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 9,299,690 shares of Common Stock as provided in Section ‎Section 2. The additional 4,218,750 Shares 9,299,690 shares of Common Stock to be sold by the Company pursuant to such option are collectively called the “Optional Shares,” and together with the Firm Shares, the “Shares.” The Firm Shares Securities and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered SharesSecurities.” P▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated Co. (“StifelPiper”) and ▇▇▇▇▇ Fargo Truist Securities, LLC Inc. (“▇▇▇▇▇ FargoTruist”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaPraxis Precision Medicines, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 3,025,480 shares (the “Firm Shares”) of its common stock, par value $0.00000002 0.0001 per share (the “Common Stock”) and (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase up to 318,470 shares of Common Stock (the “Warrant Shares”). ) at an exercise price of $0.0001 per share in the form attached hereto as Exhibit A. The 28,125,000 3,025,480 Firm Shares and Pre-Funded Warrants to purchase up to 318,470 shares of Common Stock to be sold by the Company are called the “Firm SharesSecurities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 501,592 shares of Common Stock as provided in Section 2‎Section 2 of this Agreement. The additional 4,218,750 Shares 501,592 shares of Common Stock to be sold by the Company pursuant to such option are collectively called the “Optional Shares,” and together with the Firm Shares, the “Shares.” The Firm Shares Securities and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered SharesSecurities.” TD Securities (USA) LLC (“T▇ ▇▇▇▇▇”), P▇, ▇▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated Co. (“StifelPiper”) ), and ▇▇▇▇▇ Fargo Guggenheim Securities, LLC (“▇▇▇▇▇ FargoGuggenheim”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Agenus Inc., a Delaware corporation (the “Company”), proposes to issue and sell an aggregate of 19,335,653 shares of common stock, par value $0.01 per share (the “Common Stock”), of the Company (the “Firm Shares”) to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock), par value $0.00000002 per share for whom you are acting as representative (the “SharesRepresentative”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to the Underwriters an option options to purchase up to an aggregate of 2,900,347 additional 4,218,750 Shares shares of Common Stock (the “Option Shares”) as provided in Section 24 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is options are exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇You have advised the Company that the Underwriters propose to make a public offering of the Shares as soon as you deem advisable after the Pricing Agreement hereinafter defined has been executed and delivered. Prior to the purchase and public offering of the Shares by the several Underwriters, ▇▇▇▇▇▇▇▇ & Companythe Company and the Representative, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives acting on behalf of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and shall enter into an agreement substantially in the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission form of Exhibit A hereto (the “CommissionPricing Agreement”) a shelf registration statement on Form S-3, File No). 333-217645, including a base prospectus (The Pricing Agreement may take the “Base Prospectus”) to be used form of an exchange of any standard form of written telecommunication between the Company and the Representative and shall specify such applicable information as is indicated in connection with the public Exhibit A hereto. The offering and sale of the Offered Shares. Such registration statementShares shall be governed by this Agreement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration StatementPricing Agreement. 1 Plus an option to acquire up to 2,900,347 additional shares to cover overallotments. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together Company hereby confirms its agreement with the BaseUnderwriters as follows:

Introductory. MEI PharmaApogee Therapeutics, Inc., a Delaware corporation (together with its predecessor entity, Apogee Therapeutics, LLC (“Apogee LLC”), the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 [●] shares of its common stock, par value $0.00000002 [●] per share (the “Shares”). The 28,125,000 [●] Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 [●] Shares as provided in Section 2. The additional 4,218,750 [●] Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” J▇▇▇▇▇▇▇▇ LLC (“Jefferies”), C▇▇▇▇ and Company, LLC (“Cowen”), S▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Guggenheim Securities, LLC (“▇▇▇▇▇ FargoGuggenheim”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with Representatives agree that up to [●] of the Securities and Exchange Commission Firm Shares to be purchased by the Underwriters (the “CommissionDirected Shares”) a shelf registration statement on Form S-3shall be reserved for sale to certain eligible directors, File No. 333-217645, including a base prospectus (officers and employees of the “Base Prospectus”) to be used in connection Company and persons having business relationships with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder Company (collectively, the “Securities ActParticipants”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a as part thereof at of the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale distribution of the Offered Shares is called by the Underwriters (the “Rule 462(bDirected Share Program”) Registration Statement,” subject to the terms of this Agreement, the applicable rules, regulations and from interpretations of the Financial Industry Regulatory Authority, Inc. (“FINRA”) and all other applicable laws, rule and regulations. The Directed Share Program shall be administered by Jefferies. To the extent that the Directed Shares are not orally confirmed for purchase by the Participants by the end of the first business day after the date and time of filing this Agreement, such Directed Shares may be offered to the public by the Underwriters as part of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the public offering thereof (the “Preliminary Prospectus Supplement”), together with the Basecontemplated hereby.

Introductory. MEI PharmaVail Banks, Inc., a Delaware Colorado corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A 1,440,000 shares (the “Underwriters”"Primary Shares") an aggregate of 28,125,000 shares of its common stockauthorized but unissued Common Stock, par value $0.00000002 1.00 per share ("Common Stock"), and VBI Employee Limited Partnership and ▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇ (the “"Selling Shareholders") propose to sell 120,000 and 40,000 shares, respectively, of Common Stock ("Secondary Shares”"), to ▇. ▇. ▇▇▇▇▇▇▇ & Sons, Inc. and ▇▇▇▇▇▇ & ▇▇▇▇▇▇ Incorporated and to each of the other underwriters (the "Underwriters") for whom ▇. ▇. ▇▇▇▇▇▇▇ & Sons, Inc. and ▇▇▇▇▇▇ & ▇▇▇▇▇▇ Incorporated are acting as representatives (in such capacity, the "Representatives"). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to an 240,000 additional 4,218,750 Shares shares of Common Stock ("Additional Shares") as provided in Section 25 hereof. The additional 4,218,750 Primary Shares and Secondary Shares are referred to be sold by herein as the Company pursuant to such option are collectively called "Firm Shares," and the “Optional Firm Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Additional Shares, are hereinafter collectively called referred to as the “Offered "Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Shareholders that you propose to act as representatives make a public offering of the several Underwriters (in such capacityShares as soon as you deem advisable after the registration statement hereinafter referred to becomes effective, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwritersif it has not yet become effective, and the term “Underwriters” shall mean either Pricing Agreement hereinafter defined has been executed and delivered. _______________ * Plus an option to acquire up to 240,000 additional shares to cover over allotments. Prior to the singular or the plural, as the context requires. The Company has prepared purchase and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statementShares by the Underwriters, as amendedthe Company, including the financial statements, exhibits Selling Shareholders and schedules thereto, the Representatives shall enter into an agreement substantially in the form of Exhibit A hereto ("Pricing Agreement"). The Pricing Agreement may take the form of an exchange of any standard form of written telecommunication between the Company, the Selling Shareholders and the Representatives and shall specify such applicable information as is indicated in which it became effective under Exhibit A hereto. The offering of the Securities Act of 1933Shares will be governed by this Agreement, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration StatementPricing Agreement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares Company and the offering thereof (Selling Shareholders hereby confirm their agreements with respect to the “Preliminary Prospectus Supplement”), together with purchase of the BaseShares by the Underwriters as follows:

Introductory. MEI PharmaThe Company has entered into a forward stock purchase transaction with Deutsche Bank AG, Inc., a Delaware corporation London Branch (the “CompanyForward Purchaser”)) as set forth in a separate letter agreement dated the date hereof, proposes to issue and sell to the several underwriters named in Schedule a copy of which is attached hereto as Exhibit A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “SharesInitial Confirmation”). The 28,125,000 Shares to be sold by Company may also enter into additional forward stock purchase transactions with the Company are called Forward Purchaser on substantially similar terms (each, a “Subsequent Confirmation” and, together with the Initial Confirmation, the “Firm Shares.” In addition, the Confirmations”). The Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called also entered into a distribution agency agreement (the “Optional Shares.” The Firm Shares andAdditional Distribution Agency Agreement”), if and to dated the extent such option is exerciseddate hereof, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇with ▇▇▇▇▇▇▇ & CompanyLynch, Incorporated (“Stifel”) and Pierce, ▇▇▇▇▇▇ Fargo Securities, LLC (“& ▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission Incorporated (the “CommissionAdditional Manager”) and a shelf registration statement on Form S-3forward stock purchase transaction with an affiliate of the Additional Manager and the Company may enter into additional forward stock purchase transactions with an affiliate of the Additional Manager. Subject to the terms and conditions herein and therein, File No. 333-217645under the Confirmation and, if applicable, the Subsequent Confirmations, the Company will deliver to the Forward Purchaser, or an affiliate thereof (including a base prospectus the Manager), up to the number of shares of the Company’s common stock, par value $0.01 per share (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActCommon Stock”), including all documents incorporated or deemed to as may be incorporated by reference therein and any information deemed to be a part thereof at sold in accordance with the time terms of effectiveness pursuant to Rule 430A or 430B under the Securities Actthis Agreement. In connection therewith, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the Forward Purchaser understand that the Forward Purchaser, through the Manager, as sales agent, will effect sales of shares of Common Stock having an aggregate offering thereof price not in excess of $400,000,000 (the “Preliminary Prospectus SupplementShares”) on the terms set forth in Section 2 of this Amended and Restated Distribution Agency Agreement (the “Agreement”), together with the Base.

Introductory. MEI PharmaCodiak BioSciences, Inc., a Delaware corporation (the “Company”), proposes proposes, subject to the terms and conditions stated in this agreement (this “Agreement”), to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 (i) 13,333,333 shares of its common stock, par value $0.00000002 0.0001 per share (the “Shares”) and (ii) warrants to purchase up to 13,333,333 Shares in the form set forth in Exhibit F hereto (the “Warrants”). The 28,125,000 Shares underlying the Warrants are herein called the “Warrant Shares.” The 13,333,333 Shares to be sold by the Company are called the “Firm Shares,” and the 13,333,333 Warrants to be sold by the Company are called the “Firm Warrants.” In addition, the Company has granted to the Underwriters an option to purchase up to (i) an additional 4,218,750 1,999,999 Shares (the “Optional Shares”) and (ii) an additional 1,999,999 Warrants (the “Optional Warrants”) as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and Firm Warrants and, if and to the extent such option is exercised, the Optional Shares and Optional Warrants, including the Warrant Shares, are collectively called the “Offered Shares.” Each Firm Share and, if and to the extent such option is exercised, each Optional Share is being sold together with one Warrant to purchase one Share at an exercise price of $1.875 per whole Share. ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “RepresentativesRepresentative” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645333- 260781, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseRule

Introductory. MEI Pharma, Inc.Micrus Endovascular Corporation, a Delaware corporation (the “Company”), proposes has an authorized capital stock consisting of (i) 50,000,000 shares, $0.01 par value per share, of Common Stock on the date hereof (“Common Stock”), of which [ ] shares were outstanding as of [ , 2006], and (ii) and [ ] shares of Preferred Stock, $0.01 par value per share on the date hereof, none of which were outstanding as of [ , 2006]. The stockholders named in Schedule B (“Selling Stockholders”) propose to issue and sell [ ] shares of Common Stock (“Firm Shares”) to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock), par value $0.00000002 per share (the “Shares”)who are acting severally and not jointly. The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to an [ ] additional 4,218,750 Shares shares of Common Stock (“Option Shares”) as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) You have agreed advised the Company that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacityShares as soon as you deem advisable after the registration statement hereinafter referred to becomes effective, if it has not yet become effective. 1 Plus an option to acquire up to [ ] additional Shares from the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresCompany to cover overallotments. The Company has prepared and filed each Selling Stockholder hereby confirm their respective agreements with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, Underwriters as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaThe Real Good Food Company, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 [_____] shares of its Class A common stock, par value $0.00000002 0.0001 per share (the “Shares”). The 28,125,000 [_____] Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 [_____] Shares and the stockholder of the Company named in Schedule B (the “Selling Stockholder”) has granted to the Underwriters an option to purchase up to an additional [_____] Shares, all as provided in Section 2. The additional 4,218,750 [_____] Shares to which may be sold by the Company and the additional [_____] Shares which may be sold by the Selling Stockholder pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇ LLC (“Jefferies”) and ▇▇▇▇▇▇▇ ▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC L.L.C. (“▇▇▇▇▇▇▇ Fargo▇▇▇▇▇”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To The Shares to be outstanding after giving effect to the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, sales contemplated hereby and the term “Underwriters” shall mean either the singular or the plural, Reorganization Transactions (as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”defined herein), together with the Baseshares of Class B common stock, par value $0.0001 per share (the “Class B Common Stock”), of the Company are hereinafter referred to as the “Common Stock”. In connection with the offering contemplated by this Underwriting Agreement (this “Agreement”), the Company will become the sole managing member of Real Good Foods, LLC, a Delaware limited liability company (“RGF LLC”), and will directly own a [____]% membership interest of RGF LLC, assuming no exercise of the option to purchase Additional Shares described in Section 2 hereof. To the extent the context requires, any reference in this Agreement to the “Reorganization Transactions” shall have the meanings ascribed to the term the “Reorganization” in the Prospectus (as defined below). In connection with the offering contemplated by this Agreement and the Reorganization Transactions, (a) the Company will enter into a tax receivable agreement (the “Tax Receivable Agreement”) with all of RGF LLC’s members (the “Members”); (b) the Company will enter into a registration rights agreement with RGF LLC and the Members (the “Registration Rights Agreement”); (c) the Company will enter into an exchange agreement with RGF LLC and the Members (the “Exchange Agreement”); (d) the holders (the “Holders”) of the Company’s outstanding convertible promissory notes (the “Notes”) will receive shares of Class A Common Stock and Class B Common Stock upon the automatic conversion of the Notes, (e) RGF LLC will amend and restate its operating agreement to (i) appoint the Company as the sole managing member of RGF LLC; (ii) replace the membership interests currently held by the Members such that (1) all the Class A units in RGF LLC will be owned exclusively by the Company and (2) all the Class B units of RGF LLC will be owned exclusively by the Members in proportion to their percentage of ownership interests in RGF LLC immediately prior to the completion of the offering contemplated by this Agreement and by the Holders following the conversion of the Notes (as so amended and restated, the “RGF LLC Agreement”); (f) the Company will issue Class B Common Stock such that the Class B Common Stock will be owned exclusively by the Members in proportion to their percentage ownership in RGF LLC immediately prior to the completion of the offering contemplated by this Agreement and by the Holders following the conversion of the Notes; (g) the Company will amend and restate its certificate of incorporation (as so amended and restated, the “Amended and Restated Charter”) and (h) the Company will use the net proceeds the offering of the Offered Shares to purchase newly issued Class A units of RGF LLC pursuant to a subscription agreement (the “Subscription Agreement”). This Agreement, the RGF LLC Agreement, the Amended and Restated Charter, the Tax Receivable Agreement, the Registration Rights Agreement and the Subscription Agreement are collectively referred to herein as the “Transaction Documents.”

Introductory. MEI Pharma, Inc.DUKE ENERGY CORPORATION, a Delaware corporation (the “CompanyCorporation”), proposes to issue and sell to J.▇. ▇▇▇▇▇▇ Securities LLC, as agent and affiliate of the Forward Purchaser (as defined below) and/or seller of Shares (as defined below) hereunder (the “Forward Seller”), at the request of the Corporation in connection with the Forward Sale Agreement (as defined below), confirm their respective agreements with you and each of the several underwriters named Underwriters listed in Schedule A I hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), with respect to, subject to Section 11 hereof, (a) the sale by the Forward Seller and the purchase by the Underwriters, in each case acting severally and not jointly, of an aggregate of 28,125,000 25,000,000 shares of its common stock, par value $0.00000002 0.001 per share share, of the Corporation (such common stock, the “Common Stock,” and such shares of Common Stock, the “Borrowed Underwritten Shares”) and (b) the grant to the Underwriters, acting severally and not jointly, of the option described in Section 4 hereof to purchase all or any portion of an additional 3,750,000 shares of Common Stock (the “Borrowed Option Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of Corporation understands that the several Underwriters propose to offer the Shares for sale upon the terms and conditions contemplated by (in such capacityi) this Agreement and (ii) the Base Prospectus, the “Representatives”Preliminary Prospectus (each, as defined in Section 2 hereof), any Permitted Free Writing Prospectus (as defined in Section 7 hereof) in connection with issued at or prior to the offering Applicable Time (as defined below) and sale of the Offered Shares. To the extent there are no additional underwriters listed information included on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, II hereto (such documents and the term “Underwriters” shall mean either the singular or the plural, information referred to in this subclause (ii) are collectively referred to as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActPricing Disclosure Package”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaNovatel Wireless, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 4,250,000 shares of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”); and the stockholders of the Company named in Schedule B (collectively, the “Selling Stockholders”) severally propose to sell to the Underwriters an aggregate of 3,250,000 shares of Common Stock. The 28,125,000 Shares 4,250,000 shares of Common Stock to be sold by the Company and the 3,250,000 shares of Common Stock to be sold by the Selling Stockholders are collectively called the “Firm Common Shares.” ”. In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 600,000 shares of Common Stock and the Selling Stockholders have severally granted to the Underwriters an option to purchase up to an additional 525,000 shares of Common Stock, each Selling Stockholder selling up to the amount set forth opposite such Selling Stockholder’s name in Schedule B, all as provided in Section 2. The additional 4,218,750 Shares 600,000 shares to be sold by the Company and the additional 525,000 shares to be sold by the Selling Stockholders pursuant to such option are collectively called the “Optional Common Shares.” ”. The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are collectively called the “Offered Common Shares”. Banc of America Securities LLC (“BAS”), ▇.” ▇. ▇▇▇▇▇▇ Securities Inc. (“▇.▇. ▇▇▇▇▇▇”), ▇▇ ▇▇▇▇▇ & Co., LLC, ▇▇▇▇▇▇ ▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, Partners LLC (“▇▇▇▇▇ Fargo”) and ThinkEquity Partners LLC have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Common Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645114116), including which contains a base form of prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Common Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, 1933 and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B Rule 434 under the Securities Act or the Securities Exchange Act of 1934 and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” ”. Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” ”, and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16Such prospectus, 2019 describing in the Offered Shares and form first used by the offering thereof (Underwriters to confirm sales of the Common Shares, is called the “Preliminary Prospectus”. All references in this Agreement to the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus, the Prospectus Supplementor any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System (“▇▇▇▇▇”). All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement or the Prospectus (and all other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which is or is deemed to be incorporated by reference in the Registration Statement or the Prospectus, together as the case may be; and all references in this Agreement to amendments or supplements to the Registration Statement or the Prospectus shall be deemed to mean and include the filing of any document under the Exchange Act which is or is deemed to be incorporated by reference in the Registration Statement or the Prospectus, as the case may be. The Company and each of the Selling Stockholders hereby confirm their respective agreements with the BaseUnderwriters as follows:

Introductory. MEI PharmaContinental Airlines, Inc., a Delaware corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A Lehman Brothers Inc. (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company"Initial Purchaser") $250,000,000 aggregate principal amount of its 9 1/2 % Senior Notes due 2001 (the "Notes") on the terms and conditions stated herein. The Notes are to be issued pursuant to an indenture to be dated as of December 10, Incorporated 1996 (“Stifel”the "Indenture") and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of between the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, Company and the term “Underwriters” shall mean either trustee named therein (the singular "Trustee"). Capitalized terms used but not defined herein have the meanings to be assigned to them in the Offering Memorandum (as defined below) or the plural, as the context requiresIndenture. The Company understands that the Initial Purchaser proposes to make an offering of the Notes on the terms, subject to the conditions and in the manner to be set forth in the Offering Memorandum and Section 4 hereof, as soon as the Initial Purchaser deems advisable after this Agreement has prepared been executed and filed delivered. The holders of the Notes will be entitled to the benefits of a Registration Rights Agreement, in a form reasonably satisfactory to the Initial Purchaser (the "Registration Rights Agreement"), pursuant to which the Company will file a registration statement (the "Registration Statement") with the Securities and Exchange Commission (the “"Commission”") a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus registering the Exchange Notes referred to in such Registration Rights Agreement (the “Base Prospectus”"Exchange Notes") to be used in connection with or the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B Notes under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the . The Company pursuant to Rule 462(b) under the Securities Act in connection hereby agrees with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseInitial Purchaser as follows:

Introductory. MEI Pharma, ALX Oncology Holdings Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 7,370,690 shares (the “Shares”) of its common stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”) and (ii) pre-funded warrants of the Company to purchase an aggregate of 1,250,000 Shares (the “Pre-Funded Warrants”). The 28,125,000 7,370,690 Shares to be sold by the Company are called the “Firm Shares” and, together with the Pre-Funded Warrants, are referred to herein as the “Firm Securities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 1,293,103 Shares as provided in Section 2. The additional 4,218,750 1,293,103 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares” and, together with the Pre-Funded Warrants, are referred to herein as the “Offered Securities.” ▇▇▇▇▇ ▇▇, ▇▇▇▇▇ & Co. (“▇▇▇▇▇ ▇▇▇▇▇▇▇”) and ▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇▇▇ & Company, Incorporated Co. (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoCantor”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. As used herein, “Warrant Shares” means the Shares issuable upon exercise of the Pre-Funded Warrants. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645263863, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered SharesSecurities. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseany

Introductory. MEI Pharma, A▇▇▇▇-▇▇▇▇▇▇▇▇ Energy Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 6,000,000 shares (the “Firm Shares”) of its common stockCommon Stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 900,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Shares, are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have . RBC Capital Markets Corporation has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To As more fully described in the extent there are no additional underwriters listed on Schedule ARegistration Statement (as defined below), the term Company purchased substantially all of the assets of Oil & Gas Rental Services, Inc. (“Representatives” as used herein shall mean youOil & Gas Rental”) on December 18, 2006. The purchase by the Company of substantially all of the assets of Oil & Gas Rental, as Underwritersdescribed in the Registration Statement, is referred to herein as the “Acquisition.” In connection with the Acquisition, the Company (a) received a limited waiver of certain provisions of Sections 2.04, 7.01 and 7.04 of the Company’s $25 million senior secured credit facility among the Company, each lender from time to time party thereto, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission Royal Bank of Canada (the “CommissionBank Credit Facility”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus and (b) will (i) offer and sell the Shares contemplated by this Agreement and (ii) offer and sell the Company’s Senior Notes due 2017 (the “Base ProspectusNotes”) pursuant to be used in connection with a purchase agreement dated January 24, 2007, among the public offering and sale of Company, the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, guarantors and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statementinitial purchasers named therein. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”)proceeds of this offering, together with the Baseproceeds from the offering of the Notes, will be used to repay the debt outstanding under the Company’s $300 million bridge loan facility, which the Company incurred to finance the Acquisition. The aforementioned transactions are collectively referred to herein as the “Transactions.”

Introductory. MEI Pharma, Inc.▇▇▇▇▇ Education Company, a Delaware Colorado ------------ corporation (the “"Company”"), proposes to issue and sell 5,800,000 shares of its authorized but unissued Class A Common Stock, $.01 par value per share (the "Common Stock"), and certain shareholders of the Company named in Schedule B annexed hereto (the "Selling Shareholders") propose to sell an aggregate of 1,100,000 shares of the Company's issued and outstanding Common Stock to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”"). The 28,125,000 Shares Said shares, aggregating a total of 6,900,000 shares, are herein referred to be sold by as the Company are called the “"Firm Common Shares.” " In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to _________ additional shares of Common Stock, and the Selling Shareholders propose to grant to the Underwriters an option to purchase up to ________ additional 4,218,750 Shares shares of Common Stock (such ________ shares and ________ shares, aggregating a total of 1,035,000 shares, being referred to as the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Shares Common Shares, are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Shareholders that the Underwriters propose to act as representatives make a public offering of the several Underwriters (in such capacity, Common Shares on the “Representatives”) in connection with the offering and sale effective date of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aregistration statement hereinafter referred to, the term “Representatives” or as used herein shall mean you, soon thereafter as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresin their judgment is advisable. The Company has prepared and filed the Selling Shareholders hereby confirm their respective agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI PharmaApogee Therapeutics, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 6,951,221 shares of its common stock, par value $0.00000002 0.00001 per share (the “Shares”) and (ii) pre-funded warrants to purchase an aggregate of 365,853 Shares in a form to be mutually agreed upon by the Company and the Representatives (the “Pre-Funded Warrants”). The 28,125,000 6,951,221 Shares to be sold by the Company are called the “Firm Shares” and together with the Pre-Funded Warrants to be sold by the Company are called the “Firm Securities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 1,097,561 Shares as provided in Section ‎Section 2. The additional 4,218,750 1,097,561 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares” and the Optional Shares, if and to the extent such option is exercised, together with the Firm Shares are called the “Offered Shares.” The Firm Shares Securities and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered SharesSecurities.” ▇▇▇▇▇▇As used herein, “Warrant Shares” means the Shares issuable upon exercise of the Pre-Funded Warrants. J▇▇▇▇▇▇▇▇ & Company, Incorporated LLC (“Stifel”) and J▇▇▇▇▇ Fargo ▇▇▇▇”), BofA Securities, Inc. (“BofA”), Guggenheim Securities, LLC (“Guggenheim Securities”) and TD Securities (USA) LLC (“T▇ ▇▇▇▇▇ Fargo▇”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaThis Agreement, Inc.effective as of the date first set forth above, a Delaware corporation amends and restates and replaces in its entirety the Sales Agency Agreement dated as of August 18, 2009 (the “CompanyPrior Sales Agreement”), proposes to issue between CHICAGO BRIDGE & IRON COMPANY N.V., a company with limited liability organized and sell to existing under the several underwriters named laws of The Netherlands, established in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of Amsterdam, having its common stockcorporate seat in The Hague and address at ▇▇▇▇▇▇▇▇▇▇▇▇ ▇▇, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition▇▇▇▇ ▇▇, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇ ▇▇▇▇▇, ▇▇▇ ▇▇▇▇▇▇▇▇▇▇▇ & (the “Company”), Incorporated and Credit Agricole Securities (USA) Inc., as sales agent (the “StifelAgent”), pursuant to which the Company proposed to issue and sale up to 10,000,000 shares of the Company’s common stock, par value Euro 0.01 per share (the “Common Stock”), and pursuant to which 2,448,683 shares of Common Stock were issued and sold (the “Sold Units”) thereunder. The Company proposes to issue and ▇▇▇▇▇ Fargo Securities, LLC sell from time to time through the Agent an offering of up to 7,551,317 shares (the “▇▇▇▇▇ FargoShares”) have agreed of its Common Stock, by any method permitted by law deemed to act be an “at-the-market” offering as representatives defined in Rule 415 of the several Underwriters Securities Act (in such capacityas defined below), including, without limitation, sales made directly on the New York Stock Exchange (the “RepresentativesNYSE”), on any other existing trading market for the Shares or to or through a market maker (the “ATM Program”). It is understood and agreed by the parties hereto that: (a) in connection with the offering representations, warranties, agreements, indemnities and covenants applicable to the sale of the Offered Shares. To Sold Units are limited to those as set forth in the extent there Prior Sales Agreement, and (b) that the Shares offered hereby and hereunder are no additional underwriters listed on Schedule Anot governed by, and are in addition to and do not include the Sold Units offered pursuant to, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresPrior Sales Agreement. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a an automatic shelf registration statement on Form S-3, S-3 (File No. 333-217645160852), including which contains a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of securities (the Offered “Shelf Securities”), including the Shares, to be issued from time to time by the Company. Such registration statement, as amended, including filed with the financial statements, exhibits and schedules thereto, in the form in which it became effective Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including the financial statements, exhibits and schedules thereto and all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act or the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement As used herein, the term “Registration StatementProspectus” shall include mean the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing to the Offered Base Prospectus that describes the Shares and the offering thereof pursuant to the ATM Program (the “Preliminary Prospectus Supplement”), together with the BaseBase Prospectus, in the form

Introductory. MEI PharmaVirgin Galactic Holdings, Inc., a Delaware corporation (the “Company”), proposes to issue agrees with Credit Suisse Securities (USA) LLC and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇▇▇ & CompanyCo. LLC, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional several underwriters listed on named in Schedule AA hereto (collectively, the term “Representatives” as used herein shall mean youUnderwriters”) to issue and sell to the several Underwriters [•] shares (the “Firm Shares”) of its common stock, as $0.0001 par value (“Common Stock”), on the terms set forth in this Underwriting Agreement (this “Agreement”). The Company also agrees to sell to the several Underwriters, at the option of the Underwriters, an aggregate of not more than [•] additional shares of its Common Stock (“Optional Shares”). The Firm Shares and the term Optional Shares are herein collectively called the “Underwriters” shall mean either the singular or the plural, as the context requiresShares”. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”as defined below) a shelf registration statement statement, on Form S-3, S-1 (File No. 333-217645333-[•]), including a base prospectus (the “Base Prospectus”) to be used in connection with covering the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective Shares under the Securities Act of 1933, as amended, amended (the “1933 Act”) and the rules and regulations promulgated thereunder (collectively, the “Securities Act1933 Act Regulations”), including a related preliminary prospectus or prospectuses. At any particular time, this initial registration statement, in the form then on file with the Commission, including all documents incorporated or information contained in the registration statement (if any) pursuant to Rule 462(b) and then deemed to be a part of the initial registration statement, and all 430A Information and 430C Information, that in any case has not then been superseded or modified, shall be referred to as the “Initial Registration Statement”. The Company may also have filed, or may file with the Commission, a Rule 462(b) registration statement covering the registration of the Shares. At any particular time, this Rule 462(b) registration statement, in the form then on file with the Commission, including the contents of the Initial Registration Statement incorporated by reference therein and including all 430A Information and all 430C Information, that in any information deemed case has not then been superseded or modified, shall be referred to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called as the “Additional Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act ”. As used in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basethis Agreement:

Introductory. MEI Pharma, Inc.Addus HomeCare Corporation, a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 1,075,267 shares (the “Primary Firm Shares”) of its common stock, par value $0.00000002 0.001 per share (the “Shares”); and the stockholder of the Company named in Schedule B (the “Selling Stockholder”) propose to sell to the Underwriters an aggregate of 1,024,733 Shares (the “Secondary Offered Shares”). The 28,125,000 Primary Firm Shares to be sold by the Company and the Secondary Offered Shares to be sold by the Selling Stockholder are collectively called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 315,000 Shares (the “Optional Shares”), as provided in Section 2. The additional 4,218,750 Primary Firm Shares and, if and to be sold by the Company pursuant to extent such option is exercised, the Optional Shares are collectively called the “Optional Primary Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇▇▇▇ LLC (“Jefferies”), ▇RBC Capital Markets, LLC (“RBC”) and ▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities& Associates, LLC Inc. (“▇▇▇▇▇▇▇ Fargo▇▇▇▇▇”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645214988, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseis

Introductory. MEI Pharma, PolyMedix Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A ) is offering (the “UnderwritersOffering”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided $15 million of Units, subject to any agreed upon increase in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”compliance with Rule 462(b)(3) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder amended (collectively, the “Securities Act”) (the “Units”), including all documents incorporated or deemed each consisting of one share of the class of common stock of the Company (the “Shares”) and a warrant, exercisable for approximately five years, to purchase one share of the class of common stock of the Company (the “Warrants” and together with the Shares, the “Securities”), in an offering at a purchase price per Unit to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and determined after the date hereof by discussions between us. ▇▇▇▇▇▇ Securities LLC and time of filing of Fordham Financial Management, Inc. will market the Units on the terms described in the Base Prospectus and any Prospectus Supplement (as such Rule 462(bterms are hereinafter defined) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof as co-placement agents (the “Preliminary Prospectus SupplementPlacement Agents”)) on a “best-efforts” basis. Each Placement Agent agrees that it will use its reasonable efforts to assist the Company in identifying, together with evaluating and approaching prospective purchasers of the BaseUnits but each Placement Agent disclaims any agreement, expressed or implied, in this Co-Placement Agent Agreement (the “Agreement”) or otherwise, that it will be successful in placing the Units. Notwithstanding anything in this Agreement to the contrary, the Company shall have the sole and absolute discretion to accept or not accept, in whole or in part, the terms of any subscription for Units. Prior to filing the Registration Statement, the Company will obtain the approval of the Placement Agents as to the anticipated price range of the Unit offering and warrant exercise price. This Agreement amends and restates in its entirety the Co-Placement Agent Agreement dated May 21, 2008.

Introductory. MEI PharmaThe Company has entered into a forward stock purchase transaction with Deutsche Bank AG, Inc., a Delaware corporation London Branch (the “CompanyForward Purchaser”)) as set forth in a separate letter agreement dated the date hereof, proposes to issue and sell to the several underwriters named in Schedule a copy of which is attached hereto as Exhibit A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “SharesInitial Confirmation”). The 28,125,000 Shares to be sold by Company may also enter into additional forward stock purchase transactions with the Company are called Forward Purchaser on substantially similar terms (each, a “Subsequent Confirmation” and, together with the Initial Confirmation, the “Firm Shares.” In addition, the Confirmations”). The Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called also entered into a distribution agency agreement (the “Optional Shares.” The Firm Shares andAdditional Distribution Agency Agreement”), if and to dated the extent such option is exerciseddate hereof, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇with ▇▇▇▇▇▇▇ & CompanyLynch, Incorporated (“Stifel”) and Pierce, ▇▇▇▇▇▇ Fargo Securities, LLC (“& ▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission Incorporated (the “CommissionAdditional Manager”) and a shelf registration statement on Form S-3forward stock purchase transaction with an affiliate of the Additional Manager and the Company may enter into additional forward stock purchase transactions with an affiliate of the Additional Manager. Subject to the terms and conditions herein and therein, File No. 333-217645under the Confirmation and, if applicable, the Subsequent Confirmations, the Company will deliver to the Forward Purchaser, or an affiliate thereof (including a base prospectus the Manager), up to the number of shares of the Company’s common stock, par value $0.01 per share (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActCommon Stock”), including all documents incorporated or deemed to as may be incorporated by reference therein and any information deemed to be a part thereof at sold in accordance with the time terms of effectiveness pursuant to Rule 430A or 430B under the Securities Actthis Agreement. In connection therewith, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the Forward Purchaser understand that the Forward Purchaser, through the Manager, as sales agent, will effect sales of shares of Common Stock having an aggregate offering thereof price not in excess of $300,000,000 (the “Preliminary Prospectus SupplementShares”) on the terms set forth in Section 2 of this Distribution Agency Agreement (the “Agreement”), together with the Base.

Introductory. MEI Pharma, Inc.Gladstone Land Corporation, a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 1,000,000 shares (the “Shares”) of its common stock6.375% Series A Cumulative Term Preferred Stock, par value $0.00000002 0.001 per share (the “SharesPreferred Stock”). The 28,125,000 Company is the indirect general partner of Gladstone Land Limited Partnership (the “Operating Partnership”), a Delaware limited partnership that serves as the Company’s primary operating partnership subsidiary. The 1,000,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted agreed to sell to the Underwriters an option Underwriters, subject to purchase the terms and conditions stated herein, up to an additional 4,218,750 150,000 Shares as provided in Section 2to cover the over-allotment by the Underwriters, if any. The additional 4,218,750 150,000 Shares to be sold by the Company pursuant to such over-allotment option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such over-allotment option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇ ▇, ▇▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoJanney”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule AA hereto, the term “RepresentativesRepresentative” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645194539, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basethe

Introductory. MEI PharmaUlta Salon, Inc.Cosmetics & Fragrance, a Delaware corporation Inc. (the “Company”), proposes a Delaware corporation, has an authorized capital stock consisting of 70,000,000 shares, $0.01 par value, of Preferred Stock, of which no shares will be outstanding as of the First Closing Date hereinafter defined, and 400,000,000 shares, $0.01 par value, of Common Stock (“Common Stock”), of which 62,883,482 shares were outstanding as of May 1, 2012, and no other shares of Common Stock will have been issued as of the First Closing Date, except for shares of Common Stock issued upon the exercise of stock options outstanding as of May 1, 2012. Certain stockholders of the Company (as named in Schedule B, the “Selling Stockholders”) propose to issue sell in the aggregate 7,000,000 shares of the Company’s issued and sell outstanding Common Stock to the several underwriters named in Schedule A (the “Underwriters”) an aggregate ), who are acting severally and not jointly. Collectively, such total of 28,125,000 7,000,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares Common Stock proposed to be sold by the Company are called Selling Stockholders is hereinafter referred to as the “Firm Shares.” In addition, one Selling Stockholder, as identified on Schedule B (the Company has granted “Option Stockholder”), proposes to grant to the Underwriters an the option to purchase up to an aggregate of 1,050,000 additional 4,218,750 Shares shares of Common Stock (the “Option Shares”) as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such the Underwriters’ option is exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇The Common Stock, ▇▇▇▇▇▇▇▇ including the Shares, will have attached thereto rights (the “Rights”) to purchase shares of Series A Junior Participating Preferred Stock, par value $.01 per share (the “Preferred Stock”), of the Company. The Rights are to be issued pursuant to a Stockholder Rights Agreement (the “Rights Agreement”), dated as of October 25, 2007, between the Company and American Stock Transfer & Trust Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresRights Agent. The Company has prepared and filed the Selling Stockholders hereby confirm their agreement with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, Underwriters as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaEvolus, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 [●] shares (the “Primary Firm Shares”) of its common stock, par value $0.00000002 0.00001 per share (the “Shares”) and Alphaeon Corporation, a Delaware corporation (the “Selling Stockholder”), proposes to sell to the Underwriters an aggregate of [●] Shares (the “Secondary Firm Shares”). The 28,125,000 Primary Firm Shares to be sold by the Company and the Secondary Firm Shares to be sold by the Selling Stockholder are collectively called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 [●] Shares (the “Primary Optional Shares”) and the Selling Stockholder has granted to the Underwriters an option to purchase up to an additional [●] Shares (the “Secondary Optional Shares”), all as provided in Section 2. The additional 4,218,750 Primary Optional Shares to be sold by the Company and the additional Secondary Optional Shares to be sold by the Selling Stockholder pursuant to such option are collectively called the “Optional Shares.” The Primary Firm Shares and, if and to the extent such option is exercised, the Primary Optional Shares are collectively called the “Primary Offered Shares.” The Secondary Firm Shares and, if and to the extent such option is exercised, the Secondary Optional Shares are collectively called the “Secondary Offered Shares.” The Primary Offered Shares and the Secondary Offered Shares are collectively referred to as the “Offered Shares.” Cantor ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Co. (“StifelCantor”) and ▇▇▇▇▇ Fargo Securities, Mizuho Securities USA LLC (“▇▇▇▇▇ FargoMizuho”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean youthe Representatives, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S‑1 (File No. 333-217645333‑[●]), including which contains a base form of prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16prospectus, 2019 describing in the form first used by the Underwriters to confirm sales of the Offered Shares and or in the offering thereof (form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act, is called the “Preliminary Prospectus SupplementProspectus.”), together with the Base

Introductory. MEI Pharma, Inc.Axovant Gene Therapies Ltd., a Delaware corporation company incorporated and organized under the laws of Bermuda (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 shares of its 14,031,336 common stockshares, par value $0.00000002 0.00001 per common share (the “Shares”); and (ii) pre-funded warrants to purchase an aggregate of 3,301,998 common shares at an exercise price equal to $0.00001 per share (the “Pre-Funded Warrants”). The 28,125,000 14,031,336 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 2,600,000 Shares as provided in Section 2. The additional 4,218,750 2,600,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (The Offered Shares and the Pre-Funded Warrants are collectively called the “Stifel”) and ▇▇▇▇▇ Fargo Securities, .” The Shares issuable upon exercise of the Pre-Funded Warrants are herein referred to as the “Warrant Shares.” SVB Leerink LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “RepresentativesRepresentative” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharmai3 Verticals, Inc., a Delaware corporation (the “Company”), proposes to issue and sell sell, pursuant to the terms of this Underwriting Agreement (this “Agreement”), to the several underwriters named in Schedule A hereto (the “Underwriters,” or, each, an “Underwriter”) an aggregate of 28,125,000 ), 3,250,000 shares of its common stockClass A Common Stock, $0.0001 par value $0.00000002 per share (the “SharesClass A Common Stock”) of the Company. The aggregate of 3,250,000 shares of Class A Common Stock so proposed to be sold is hereinafter referred to as the “Firm Stock.” The Company also proposes to sell to the Underwriters, upon the terms and conditions set forth in Section ‎‎3 hereof, up to an additional 487,500 shares of Class A Common Stock (the “Optional Stock”). The 28,125,000 Shares Firm Stock and the Optional Stock are hereinafter collectively referred to be sold by the Company are called as the “Firm SharesStock.” In additionBofA Securities, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if Inc. and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, Co. LLC (“▇▇▇▇▇ Fargo”) have agreed to act are acting as representatives of the several Underwriters (and in such capacity, capacity are hereinafter referred to as the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”)Class A Common Stock, together with the BaseCompany’s Class B Common Stock, $0.0001 par value per share (the “Class B Common Stock”), are referred to herein collectively as (the “Common Stock”). The net proceeds of this offering will be used to finance the Company’s repurchase of (1) 3,250,000 Class A common units from i3 Verticals, LLC, and (2) if the Underwriters exercise their option to purchase the Optional Stock in full, 487,500 Class A common units from certain continuing equity owners, in each case at a price equal to the purchase price paid by the Underwriters for the Stock as set out in Schedule C hereof and as further described in the “Use of Proceeds” section of the Prospectus (as defined below). #93375751v17 The business of the Company is conducted through i3 Verticals, LLC, a Delaware limited liability company (“i3 Verticals, LLC”), and its subsidiaries. The Company is the sole managing member of i3 Verticals, LLC. As the sole managing member of i3 Verticals, LLC, the Company operates and controls all of the business and affairs of i3 Verticals, LLC and, through i3 Verticals, LLC and its subsidiaries, conducts its business. The Company and i3 Verticals, LLC are collectively referred to herein as the “i3 Verticals Parties,” and each of the Company and i3 Verticals, LLC is sometimes individually referred to herein as an “i3 Verticals Party.”

Introductory. MEI PharmaCompass Therapeutics, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 (i) 33,290,000 shares (the “Shares”) of its common stock, par value $0.00000002 0.0001 per share (the “SharesCommon Stock”), and (ii) pre-funded warrants of the Company to purchase up to an aggregate of 6,710,000 shares of Common Stock at an exercise price of $0.0001 per share (the “Pre-Funded Warrants”). The 28,125,000 33,290,000 Shares to be sold by the Company are called the “Firm Shares.” The Firm Shares and the 6,710,000 Pre-Funded Warrants to be sold by the Company are collectively referred to as the “Firm Securities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 6,000,000 Shares as provided in Section 2. The additional 4,218,750 6,000,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares”, and together with the Pre-Funded Warrants are referred to as the “Offered Securities.” ▇▇▇▇▇▇▇▇▇ LLC (“▇▇▇▇▇▇▇▇▇”), ▇▇▇▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated Co. (“StifelPiper”) and ▇▇▇▇▇ Fargo Guggenheim Securities, LLC (“▇▇▇▇▇ FargoGuggenheim Securities”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with As used herein, “Warrant Shares” means the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale shares of Common Stock issuable upon exercise of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration StatementPre-Funded Warrants.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaApex PC Solutions, Inc., a Delaware Washington corporation (the “"Company”"), proposes to issue and sell 1,000,000 shares of its authorized but unissued Common Stock (the "Common Stock") to the several underwriters named in Schedule SCHEDULE A annexed hereto (the “"Underwriters”"). In addition, certain shareholders of the Company named in SCHEDULE B annexed hereto (the "Selling Shareholders") propose to sell an aggregate of 28,125,000 2,000,000 shares of its common stock, par value $0.00000002 per share (Common Stock to the “Shares”)Underwriters. The 28,125,000 Shares Said 1,000,000 shares to be sold and issued by the Company and 2,000,000 shares to be sold by the Company Selling Shareholders are herein called the “"Firm Common Shares.” " In addition, the Company has granted certain Selling Shareholders propose to grant to the Underwriters an option to purchase up to an 450,000 additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Shareholders that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacity, Common Shares on the “Representatives”) in connection with the offering and sale effective date of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aregistration statement hereinafter referred to, the term “Representatives” or as used herein shall mean you, soon thereafter as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresin your judgment is advisable. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale each of the Offered Shares. Such registration statement, as amended, including Selling Shareholders hereby confirm their respective agreements with respect to the financial statements, exhibits and schedules thereto, in purchase of the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI PharmaAmerican Capital Strategies, Inc.Ltd., a Delaware corporation (the “Company”), proposes to issue and sell to Citigroup Global Markets Inc. (“Citigroup”), Wachovia Bank, National Association (“Wachovia”) and ▇.▇. ▇▇▇▇▇▇ Securities Inc., (“JPMSI”) (collectively, the several underwriters “Forward Sellers”), at the request of the Company in connection with the “Forward Agreements” (as defined below) attached hereto as Exhibit A, confirm their respective agreements with the Representatives (as defined below) and each of the other Underwriters named in Schedule A attached hereto and made a part hereof (collectively, the “Underwriters”) an aggregate with respect to (a) the sale by the Company and the Forward Sellers (including the issuance and sale by the Company of 28,125,000 Common Stock (as defined below) to the Underwriters pursuant to Section 12(a) hereof), and purchase by the Underwriters, acting severally and not jointly, of their respective portions of 8,700,000 shares of its common stockCommon Stock, par value $0.00000002 per share including the Borrowed Shares (as defined below) (the “Firm Shares”) and all or any part of 1,300,000 additional shares of Common Stock (the “Option Shares”) as provided in Section 3(b) hereof (the Firm Shares and Option Shares collectively being referred to as the “Shares”). The 28,125,000 , and (b) the grant by the Company to the Underwriters of the option described in Section 3(b) hereof to purchase all or any part of the Option Shares to cover over-allotments, if any. “Common Stock” shall refer to the $0.01 par value per share of common stock of the Company. “Forward Agreement” shall refer to the following letter agreements, which relate to the forward sale by the Company of a number of shares of Common Stock of the Company equal to the number of shares of Common Stock to be borrowed and sold by the Company are called Forward Sellers pursuant to this Agreement (the “Borrowed Shares”) dated the date hereof and entered into by and between the following: (a) the Company and Citigroup (the “Citigroup Forward Agreement”), (b) the Company and Wachovia (the “Wachovia Forward Agreement”) and (c) the Company and ▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇ Bank (“JPMCB Forward Agreement”). Citigroup, Wachovia and ▇▇ ▇▇▇▇▇▇ Chase Bank are hereafter referred to as the “Forward Counterparties”. Of the Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an 700,000 shares (plus any additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be shares issued and sold by the Company pursuant to such option are collectively called Section 12(a) hereof), will be issued and sold to the Underwriters by the Company (the “Optional Company Firm Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities8,000,000 shares (subject to reduction for any shares issued and sold by the Company pursuant to Section 12(a) hereof) will be sold to the Underwriters by the Forward Sellers (the “Forward Seller Firm Shares”). Citigroup Global Markets Inc. and Wachovia Capital Markets, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) pursuant to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”) and the Investment Company Act of 1940, as amended, and the rules and regulations promulgated thereunder (the “Investment Company Act”), a registration statement on Form N-2/A for the offer and sale of an aggregate amount of $1,750,000,000 of securities (File No. 333-113859), which registration statement became effective on May 7, 2004, a copy of which has heretofore been delivered to you. Such registration statement has been amended by post-effective amendment no. 1 and post-effective amendment no. 2 filed with the Commission on July 30, 2004 and August 2, 2004, respectively, which post-effective amendments became effective on August 3, 2004, a copy of each of which has heretofore been delivered to you. Such registration statement, as amended, meets the requirements set forth in Rule 415(a)(1) under the Securities Act and complies in all other material respects with such Rule. The Company proposes to file with the Commission pursuant to Rule 497 under the Securities Act, a supplement, dated as of March 23, 2005, to the prospectus dated as of August 3, 2004, relating to the Shares and the method of distribution thereof and has previously advised you of all further information (financial and other) with respect to the Shares set forth therein. Such registration statement, including the exhibits thereto, as amended at the date hereof, is hereinafter called the “Registration Statement”; such prospectus, in the form in which it was filed with the Commission pursuant to Rule 497 under the Securities Act, is hereinafter called the “Basic Prospectus”; such supplement to the Basic Prospectus, in the form in which it will be filed with the Commission pursuant to Rule 497 under the Securities Act, is hereinafter called the “Prospectus Supplement”; and the Basic Prospectus and the Prospectus Supplement together are hereinafter called the “Prospectus”. Each prospectus, subject to completion, used in connection with a public offering is called a “preliminary prospectus”. All references in this underwriting agreement (this “Agreement”) to the Registration Statement, a preliminary prospectus, the Prospectus, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System (“▇▇▇▇▇”). All references in this Agreement to financial statements and schedules and other information which is “contained,” “included” or “stated” in the Registration Statement or the Prospectus (and all documents incorporated other references of like import) shall be deemed to mean and include all such financial statements and schedules and other information which is or is deemed to be incorporated by reference therein in the Registration Statement or the Prospectus, as the case may be; and all references in this Agreement to amendments or supplements to the Registration Statement or the Prospectus shall be deemed to mean and include the filing of any information document under the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder (the “Exchange Act”) which is or is deemed to be a part thereof at incorporated by reference in the time of effectiveness pursuant to Rule 430A Registration Statement or 430B under the Securities ActProspectus, is called as the “Registration Statement.” Any registration statement filed by the case may be. The Company pursuant to Rule 462(b) under the Securities Act in connection hereby confirms its agreements with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.Gladstone Commercial Corporation, a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 1,100,000 shares (the “Shares”) of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”). The 28,125,000 Company is the indirect general partner of Gladstone Commercial Limited Partnership (the “Operating Partnership”), a Delaware limited partnership that serves as the Company’s primary operating partnership subsidiary. The 1,100,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 165,000 Shares as provided in Section 2. The additional 4,218,750 165,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoJefferies”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule AA hereto, the term “RepresentativesRepresentative” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645169290, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16April 23, 2019 2013 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other prospectus supplement to the Base Prospectus in preliminary form that describes the Offered Shares and the offering thereof and is used prior to the filing of the Prospectus (as defined below), together with the Base

Introductory. MEI Pharma, Inc.NewLink Genetics Corporation, a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 5,000,000 shares of its common stock, par value $0.00000002 0.01 per share (the “Shares”). The 28,125,000 5,000,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 750,000 Shares as provided in Section 2. The additional 4,218,750 750,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated (“▇▇▇▇▇▇▇ ▇▇▇▇▇”) and ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Incorporated. (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. This Agreement is effective as of October 3, 2017 (the “Agreement Date”). The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645333‑205234, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefiling

Introductory. MEI PharmaICOP Digital, Inc., a Delaware Colorado corporation (the “Company”), ) proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 1,000,000 shares of its common stock, par value $0.00000002 per share (the “Shares”) of the Company’s common stock (“Common Stock”) and (ii) an aggregate of 1,000,000 redeemable warrants, each entitling the holder to purchase one share of Common Stock (each a “Warrant” and, collectively, the “Warrants”). The 28,125,000 Warrants are to be identical in form to the public warrants first issued in July 2005 and that currently trade on the Nasdaq Capital Market under the symbol “ICOPW.” The Warrants are to be issued under the terms of a Warrant Agreement (the “Warrant Agreement”) by and between the Company and ComputerShare Trust Company, Inc., as warrant agent (the “Warrant Agent”), substantially in the form most recently filed as an exhibit to the Registration Statement (hereinafter defined). The 1,000,000 Shares and the 1,000,000 Warrants to be sold by the Company are collectively called the “Firm SharesSecurities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 150,000 Shares (the “Optional Shares”) and an additional 150,000 Warrants (the “Optional Warrants”), as provided in Section 2. The additional 4,218,750 Optional Shares to be sold by the Company pursuant to such option and Optional Warrants are collectively called referred to herein as the “Optional Shares.” The Securities”). Firm Shares Securities and, if and to the extent such option is exercised, the Optional Shares Securities are collectively called the “Offered SharesSecurities.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Investment Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have Inc. has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed confirms its agreement with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, Underwriters as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaICOP Digital, Inc., a Delaware Colorado corporation (the “Company”), ) proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 1,000,000 shares of its common stock, par value $0.00000002 per share (the “Shares”) of the Company’s common stock (“Common Stock”) and (ii) an aggregate of 1,000,000 redeemable warrants, each entitling the holder to purchase one share of Common Stock (each a “Warrant” and, collectively, the “Warrants”). The 28,125,000 Warrants are to be identical in form to the public warrants first issued in July 2005 and that currently trade on the Nasdaq Capital Market under the symbol “ICOPW.” The Warrants are to be issued under the terms of a Warrant Agreement (the “Warrant Agreement”) by and between the Company and ComputerShare Investor Services, as warrant agent (the “Warrant Agent”), substantially in the form most recently filed as an exhibit to the Registration Statement (hereinafter defined). The 1,000,000 Shares and the 1,000,000 Warrants to be sold by the Company are collectively called the “Firm SharesSecurities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 150,000 Shares (the “Optional Shares”) and an additional 150,000 Warrants (the “Optional Warrants”), as provided in Section 2. The additional 4,218,750 Optional Shares to be sold by the Company pursuant to such option and Optional Warrants are collectively called referred to herein as the “Optional Shares.” The Securities”). Firm Shares Securities and, if and to the extent such option is exercised, the Optional Shares Securities are collectively called the “Offered SharesSecurities.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Investment Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have Inc. has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed confirms its agreement with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, Underwriters as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaTeam Financial, Inc.Inc. (the "Company"), a Delaware corporation bank holding company, has an authorized capital stock consisting of 10,000,000 shares of Preferred Stock, none of which were outstanding as of June __, 1999, and 50,000,000 shares of Common Stock (the “Company”"Common Stock"), of which ____________ shares were outstanding as of such date. The Company proposes to issue and sell 700,000 shares of its authorized but unissued Common Stock and a shareholder of the Company (referred to as the "Selling Shareholder" and named in Schedule B) proposes to sell 300,000 shares of the Company's issued and outstanding Common Stock to the several underwriters named in Schedule A A, as it may be amended by the Pricing Agreement hereinafter defined (the “"Underwriters”) an aggregate "), who are acting severally and not jointly. Collectively, such total of 28,125,000 1,000,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares Common Stock proposed to be sold by the Company are called and the “Selling Shareholder is hereinafter referred to as the "Firm Shares.” " In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to an 150,000 additional 4,218,750 Shares shares of Common Stock ("Option Shares") as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered "Shares.” ▇▇▇▇▇▇" You have advised the Company and the Selling Shareholder that the Underwriters propose to make a public offering of their respective portions of the Shares as soon as you deem advisable after the registration statement hereinafter referred to becomes effective, ▇▇▇▇▇▇▇▇ & if it has not yet become effective, and after the Pricing Agreement hereinafter defined has been executed and delivered. Prior to the purchase and public offering of the Shares by the several Underwriters, the Company, Incorporated (“Stifel”) the Selling Shareholder and ▇▇▇▇▇ Fargo Securitiesthe Representative, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives acting on behalf of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, enter into an agreement substantially in the form of Exhibit A hereto ("Pricing Agreement"). The Pricing Agreement may take the form of an exchange of any standard form of written communication between the Company, the Selling Shareholder and the Representative and shall specify such applicable information as is indicated in which it became effective under Exhibit A hereto. ----------------- *Plus an option to acquire up to 150,000 additional shares to cover overallotments. The offering of the Securities Act of 1933Shares will be governed by this Agreement, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration StatementPricing Agreement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares Company and the offering thereof (the “Preliminary Prospectus Supplement”), together Selling Shareholder hereby confirm their agreements with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.Gladstone Commercial Corporation, a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 1,377,500 shares (the “Shares”) of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”). The 28,125,000 Company is the indirect general partner of Gladstone Commercial Limited Partnership (the “Operating Partnership”), a Delaware limited partnership that serves as the Company’s primary operating partnership subsidiary. The 1,377,500 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 206,625 Shares as provided in Section 2. The additional 4,218,750 206,625 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoJefferies”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule AA hereto, the term “RepresentativesRepresentative” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645190931, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16November 19, 2019 2013 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseBase Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other prospectus supplement to the Base Prospectus in preliminary form that describes the Offered Shares and the offering thereof and is used prior to the filing of the Prospectus (as defined below), together with the

Introductory. MEI PharmaChiasma, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 (i) 12,500,000 shares (the “Shares”) of its common stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”), and (ii) pre-funded warrants of the Company to purchase up to an aggregate of 5,000,000 shares of Common Stock at an exercise price of 0.0001 per share (the “Pre-Funded Warrants”). The 28,125,000 12,500,000 Shares to be sold by the Company are called the “Firm Shares.” The Firm Shares and the 5,000,000 Pre-Funded Warrants to be sold by the Company are collectively referred to as the “Firm Securities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 2,625,000 Shares as provided in Section 2. The additional 4,218,750 2,625,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares”, and together with the Pre-Funded Warrants are referred to as the “Offered Securities.” ▇▇▇▇▇▇▇▇▇ LLC (“Jefferies”), ▇▇▇▇▇ ▇▇▇▇▇▇▇ & Co. (“Piper”) and Cantor ▇▇▇▇▇▇▇▇▇▇ & Company, Incorporated Co. (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoCantor”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. As used herein, “Warrant Shares” means the shares of Common Stock issuable upon exercise of the Pre-Funded Warrants. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645233654, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered SharesSecurities. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares Securities is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseJune 30,

Introductory. MEI Pharma, Inc.▇▇▇▇▇▇▇ Purina Company, a Delaware Missouri corporation (the “------------ "Company”"), proposes to issue and sell to you (the several underwriters named "Underwriters"), an aggregate amount of 6,781,000 SAILS (Stock Appreciation Income Linked Securities) consisting of its 7% Exchangeable Notes Due 2000, which are registered under the registration statement referred to in Section 3(a) (referred to herein as the "SAILS"), in such amounts to each of the Underwriters as set forth in Schedule A hereto. The SAILS will be issued under an Indenture, dated as of May 26, 1995, between the Company and The First National Bank of Chicago, as trustee ("Trustee"), as supplemented by a First Supplemental Indenture, dated as of July 29, 1997, between the “Underwriters”) an aggregate of 28,125,000 shares of its common stockCompany and the Trustee (as supplemented from time to time, par value $0.00000002 per share (the “Shares”"Indenture"). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to Underwriters will have the Underwriters an option to purchase from the Company up to an additional 4,218,750 Shares as provided in Section 2968,000 SAILS (the "Option SAILS"). The additional 4,218,750 Shares to be sold by Firm SAILS and the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares andOption SAILS, if and purchased, are hereinafter collectively referred to as the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares"SAILS.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in " In connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aforegoing Interstate Bakeries Corporation, the term “Representatives” as used herein shall mean youa Delaware corporation ("IBC"), as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “"Commission”") a shelf Form S-3 registration statement on Form S-3, File No. 333-217645, including a base prospectus with respect to 6,781,000 shares (the “Base Prospectus”"IBC Firm Shares") of common stock of IBC, par value $.01 per share ("IBC Common Stock"), plus an additional 968,000 shares of IBC Common Stock (the "IBC Option Shares") to be used in connection the extent the Underwriters exercise their over-allotment option with respect to the public offering and SAILS, for sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company as a selling stockholder (to the extent it shall so elect to deliver IBC Common Stock to holders of the SAILS at maturity thereof pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale terms of the Offered Shares SAILS), which registration statement is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statementreferred to in Section 2(a). The preliminary prospectus supplement dated December 16, 2019 describing the Offered IBC Firm Shares and the offering thereof (IBC Option Shares, if the “Preliminary Prospectus Supplement”)Options SAILS are purchased, together with are hereinafter collectively referred to as the Base"IBC Shares."

Introductory. MEI PharmaChuy’s Holdings, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 [ ] shares of its common stock, par value $0.00000002 0.01 per share (the “Shares”). The 28,125,000 [ ] Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 [ ] Shares as provided in Section 2. The additional 4,218,750 [ ] Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ Jefferies & Company, Incorporated Inc. (“StifelJefferies”) and ▇▇▇▇▇▇ Fargo Securities, LLC (“▇. ▇▇▇▇▇ Fargo& Co. Incorporated (“Baird”) have agreed to act as representatives Representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To Jefferies and Baird agree that up to [ ] of the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission Firm Shares to be purchased by them (the “CommissionDirected Shares”) a shelf registration statement on Form S-3shall be reserved for sale by Jefferies, File No. 333-217645Baird and their respective affiliates to certain eligible directors, including a base prospectus (officers and employees of the “Base Prospectus”) to be used in connection Company and persons having business relationships with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder Company (collectively, the “Securities ActParticipants”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a as part thereof at of the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale distribution of the Offered Shares is called by Jefferies and Baird (the “Rule 462(bDirected Share Program”) Registration Statement,” subject to the terms of this Agreement, the applicable rules, regulations and from interpretations of the Financial Industry Regulatory Authority, Inc. (“FINRA”) and all other applicable laws, rule and regulations. To the extent that such Directed Shares are not orally confirmed for purchase by the Participants by the end of the first business day after the date and time of filing this Agreement, such Directed Shares may be offered to the public by the Underwriters as part of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the public offering thereof (the “Preliminary Prospectus Supplement”), together with the Basecontemplated hereby.

Introductory. MEI PharmaPieris Pharmaceuticals, Inc., a Delaware Nevada corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 5,500,000 shares of its common stock, par value $0.00000002 0.001 per share (the “Shares”). The 28,125,000 5,500,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 825,000 Shares as provided in Section 2. The additional 4,218,750 825,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇Jefferies LLC (“Jefferies”), ▇▇▇▇▇▇▇▇ & and Company, Incorporated (“Stifel”) LLC and ▇▇▇▇▇ Fargo SecuritiesEvercore Group, LLC (“▇▇▇▇▇ Fargo”) L.L.C. have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645211844, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaThe stockholder named in Schedule B hereto (the “Selling Shareholder”) of Medpace Holdings, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 4,000,000 shares of its the Company’s common stock, par value $0.00000002 0.01 per share (the “Shares”), inclusive of the Repurchase Shares (as defined below). The 28,125,000 4,000,000 Shares to be sold by the Company Selling Shareholder are called the “Firm Shares.” In addition, the Company Selling Shareholder has granted to the Underwriters an option to purchase up to an additional 4,218,750 600,000 Shares as provided in Section 2. The additional 4,218,750 600,000 Shares to be sold by the Company Selling Shareholder pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated LLC (“StifelJefferies”) and ▇▇▇▇▇ Fargo Securities, Credit Suisse Securities (USA) LLC (“▇▇▇▇▇ FargoCredit Suisse”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesShares pursuant to this underwriting agreement (this “Agreement”). To Subject to the extent there are no additional underwriters listed on Schedule Asale of the Offered Shares by the Selling Shareholder to the Underwriters in compliance with the terms of this Agreement, the term “Representatives” as used herein shall mean you, as UnderwritersUnderwriters have agreed to sell to the Company, and the term Company has agreed herein to purchase from the Underwriters (the “Underwriters” shall mean either Share Repurchase”), an aggregate of 2,000,000 of the singular or Offered Shares (the plural, as the context requires“Repurchase Shares”) pursuant to Section 2 of this Agreement. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645220306, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or Rule 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseRule

Introductory. MEI Pharma, Inc.Spirit Finance Corporation, a Delaware Maryland corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A (the “"Underwriters”") an aggregate of 28,125,000 [ ] shares of its common stockCommon Stock, par value $0.00000002 0.01 per share (the “Shares”"Common Stock"). The 28,125,000 Shares [ ] shares of Common Stock to be sold by the Company are called the “"Firm Common Shares.” " In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2[ ] shares of Common Stock. The additional 4,218,750 Shares [ ] shares to be sold by the Company pursuant to such option are collectively called the “"Optional Common Shares.” " The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are collectively called the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated " Banc of America Securities LLC (“Stifel”"BAS") and ▇▇▇▇▇ Fargo Securities, LLC Citigroup Global Markets Inc. (“▇▇▇▇▇ Fargo”"Citigroup") have agreed to act as representatives of the several Underwriters (in such capacity, the “"Representatives”") in connection with the offering and sale of the Offered Common Shares. The Company and the Underwriters agree that up to [ ] of the Firm Common Shares to be purchased by the Underwriters (the "Directed Shares") shall be reserved for sale by the Underwriters to certain eligible directors, officers and employees of the Company and persons having business relationships with the Company (collectively, the "Participants"), as part of the distribution of the Common Shares by the Underwriters (the "Directed Share Program") subject to the terms of this Agreement, the applicable rules, regulations and interpretations of the National Association of Securities Dealers, Inc. (the "NASD") and all other applicable laws, rule and regulations. BAS will process the sales to the Participants under the Directed Share Program. To the extent there that such Directed Shares are no additional underwriters listed on Schedule Anot orally confirmed for purchase by the Participants by the end of the first business day after the date of this Agreement, such Directed Shares may be offered to the term “Representatives” public as used herein shall mean you, as Underwriters, and part of the term “Underwriters” shall mean either the singular or the plural, as the context requirespublic offering contemplated hereby. The Company has prepared and filed with the Securities and Exchange Commission (the “"Commission”") a shelf registration statement on Form S-3, S-11 (File No. 333-217645119810), including which contains a base form of prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Common Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, 1933 and the rules and regulations promulgated thereunder (collectively, the “"Securities Act”"), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B Rule 434 under the Securities Act, is called the “"Registration Statement.” " Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “"Rule 462(b) Registration Statement,” " and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “"Registration Statement” " shall include the Rule 462(b) Registration Statement. The Such prospectus, in the form first used by the Underwriters to confirm sales of the Common Shares, is called the "Prospectus"; provided, however, if the Company has, with the consent of BAS, elected to rely upon Rule 434 under the Securities Act, the term "Prospectus" shall mean the Company's prospectus subject to completion (each, a "preliminary prospectus") dated December , 2004 (such preliminary prospectus supplement dated December 16, 2019 describing is called the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”"Rule 434 preliminary prospectus"), together with the Baseapplicable term sheet (the "Term Sheet") prepared and filed by the Company with the Commission under Rules 434 and 424(b) under the Securities Act and all references in this Agreement to the date of the Prospectus shall mean the date of the Term Sheet. All references in this Agreement to (i) the Registration Statement, the Rule 462(b) Registration Statement, a preliminary prospectus, the Prospectus or the Term Sheet, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed with the Commission pursuant to its Electronic Data Gathering, Analysis and Retrieval System ("▇▇▇▇▇") and (ii) the Prospectus shall be deemed to include any "electronic Prospectus" provided for use in connection with the offering of the Common Shares. The Company hereby confirms its agreements with the Underwriters as follows:

Introductory. MEI Pharma, Inc., Standard Parking Corporation ("COMPANY") a Delaware corporation corporation, has an authorized capital stock consisting of [__________] shares, $[________] par value, of Common Stock (the “Company”"COMMON STOCK"), of which [________] shares were outstanding as of [____________ ____], 2004, and [_________] shares, $[________] par value, of Preferred Stock (the "PREFERRED STOCK"), of which [_________] shares were outstanding as of [_____________ ____], 2004. In connection with the offering described herein, the Company will redeem or otherwise retire all of its outstanding shares of Preferred Stock. The Company proposes to issue and sell 4,100,000 shares of its authorized but unissued Common Stock ("FIRM SHARES") to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stockA, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to as it may be sold amended by the Company Pricing Agreement hereinafter defined ("UNDERWRITERS"), who are called the “Firm Shares.” acting severally and not jointly. In addition, the Company has granted and Steamboat Industries LLC (the "SELLING STOCKHOLDER")(2) propose to grant to the Underwriters an option to purchase up to an 615,000 additional 4,218,750 Shares shares of Common Stock ("OPTION SHARES"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares"SHARES.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Stockholder that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacityShares as soon as you deem advisable after the registration statement hereinafter referred to becomes effective, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwritersif it has not yet become effective, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company Pricing Agreement hereinafter defined has prepared been executed and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementdelivered.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaHeritage-Crystal Clean, Inc., a Delaware corporation Inc. (the “Company”), a Delaware corporation, has an authorized capital stock consisting of 500,000 shares, $0.01 par value, of preferred stock (“Preferred Stock”), of which no shares will be outstanding as of the First Closing Date hereinafter defined, and 26,000,000 shares, $0.01 par value, of common stock (“Common Stock”), of which 18,501,374 are outstanding as of the date hereof, and no other shares of Common Stock will have been issued as of the First Closing Date hereinafter defined, except for shares of Common Stock issued upon the exercise of stock options outstanding as of the date hereof or shares of Common Stock issued pursuant to this Agreement. The Company proposes to issue and sell 3,100,000 shares of its authorized but unissued Common Stock (the “Firm Shares”) to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock), par value $0.00000002 per share (the “Shares”)who are acting severally and not jointly. The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to an 465,000 additional 4,218,750 Shares shares of Common Stock (the “Option Shares”) as provided in Section 24 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated You have advised the Company that the Underwriters propose to make a public offering (the “StifelOffering”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of their respective portions of the several Underwriters (in such capacityShares as soon as you deem advisable after the registration statement hereinafter referred to becomes effective, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresif it has not yet become effective. The Company has prepared and filed hereby confirms its agreement with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, Underwriters as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI PharmaTriton Systems, Inc., Inc. a Delaware Mississippi corporation (the “"Company”"), proposes to issue and sell 3,750,000 shares of its authorized but unissued Common Stock (the "Common Stock") and certain stockholders of the Company named in Schedule B annexed hereto (the "Firm Selling Stockholders" and, together with the stockholders of the Company named in Schedule C annexed hereto, the "Selling Stockholders") propose to sell an aggregate of 450,000 shares of the Company's issued and outstanding Common Stock to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an "), for whom you are acting as Representatives. Said aggregate of 28,125,000 4,200,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are herein called the “"Firm Common Shares.” " In addition, the Company has granted Selling Stockholders propose to grant to the Underwriters an option to purchase up to an 630,000 additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) " You have advised the Company and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed the Selling Stockholders that the Underwriters propose to act as representatives make a public offering of their respective portions of the several Underwriters (in such capacity, Common Shares on the “Representatives”) in connection with the offering and sale effective date of the Offered Shares. To the extent there are no additional underwriters listed on Schedule Aregistration statement hereinafter referred to, the term “Representatives” or as used herein shall mean you, soon thereafter as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresin your judgment is advisable. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale each of the Offered Shares. Such registration statement, as amended, including Selling Stockholders hereby confirm their respective agreements with respect to the financial statements, exhibits and schedules thereto, in purchase of the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed Common Shares by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI PharmaLHC Group, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 1,000,000 shares of its common stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”); and the stockholders of the Company named in Schedule B (collectively, the “Selling Stockholders”) severally propose to sell to the Underwriters an aggregate of 3,000,000 shares of Common Stock. The 28,125,000 Shares 1,000,000 shares of Common Stock to be sold by the Company and the 3,000,000 shares of Common Stock to be sold by the Selling Stockholders are collectively called the “Firm Shares.” In addition, the Company has and the Selling Stockholders have severally granted to the Underwriters an option to purchase up to an additional 4,218,750 600,000 shares of Common Stock (the “Optional Shares”), with the Company selling up to 150,000 shares and each Selling Stockholder selling up to the amount of such Optional Shares set forth opposite such Selling Stockholder’s name in Schedule B, all as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇Jefferies & Company, Inc. (“Jefferies”), CIBC World Markets Corp. and S▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645333–135024), including which contains a base form of prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basedeemed

Introductory. MEI Pharma, Inc.First Potomac Realty Trust, a Delaware corporation Maryland real estate investment trust (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares 3,000,000 of its common stockshares (the “Firm Shares”) of beneficial interest, par value $0.00000002 .001 per share (the “Common Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 450,000 Common Shares (the “Option Shares”), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇KeyBanc Capital Markets, ▇▇▇▇▇▇▇▇ & Company, Incorporated a division of McDonald Investments Inc. (“StifelKCM”) and ▇▇▇▇▇ Fargo Securities), LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To The Company is the extent there are no additional underwriters listed on Schedule Asole general partner of First Potomac Realty Investment Limited Partnership (the “Operating Partnership”), the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, a Delaware limited partnership that serves as the context requiresCompany’s primary operating partnership subsidiary. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or a registration statement on Form S-3 (File No. 333-120821), which contains a form of prospectus to be used in connection with the public offering and sale of the Shares (the “Base Prospectus”). Such registration statement, herein referred to as the “Registration Statement,” shall be deemed to include all information omitted therefrom in reliance upon Rules 430A or 430B under the Securities Act and all information incorporated by reference therein. The form of final prospectus relating to the Shares first filed by the Company with the Commission pursuant to Rule 424(b) under the Securities Act is herein referred to as the “Prospectus.” The Base Prospectus, as supplemented by any preliminary prospectus (including any preliminary prospectus supplement) relating to the Shares used prior to the date hereof is herein referred to as a “Preliminary Prospectus.” Any reference herein to the Registration Statement, any Preliminary Prospectus or the Prospectus or to any amendment or supplement to any of the foregoing documents shall be deemed to refer to and include any documents incorporated by reference therein and any information deemed to be a part thereof at supplements or amendments thereto, filed with the time Commission after the date of effectiveness pursuant to filing of the Prospectus under Rule 430A or 430B 424(b) under the Securities Act, is called and prior to the “Registration Statement.” Any registration statement filed termination of the offering of the Shares by the Underwriters. Each of the Company pursuant to Rule 462(b) under and the Securities Act in connection Operating Partnership hereby confirms its agreements with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI PharmaDerma Sciences, Inc., a Delaware Pennsylvania corporation (the “Company”), ) proposes to issue and sell to the several underwriters named in listed on Schedule A hereto (each an “Underwriter” and collectively, the “Underwriters”) an aggregate of 28,125,000 972,000 shares (the “Firm Shares”) of its common stock, par value $0.00000002 .01 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called Common Stock) and warrants (collectively, the “Firm Warrants”) to purchase up to 324,000 shares of Common Stock (the “Warrant Shares.” ”) at any time on or before February 16, 2015 (the “Warrant Expiration Date”) for. All of the terms of the Firm Warrants are set forth in the form of warrant certificate (the “Warrant Certificate”) filed as an exhibit to the Registration Statement (as defined below). In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 145,800 shares of Common Stock (the “Option Shares”) and warrants to purchase 48,600 shares of Common Stock (the “Option Warrants” as provided in Section 2. The additional 4,218,750 Shares Unless specified to the contrary, all references herein to (i) “Shares” shall be sold by deemed to include the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and the Option Shares (to the extent such the aforementioned option is has been exercised); (ii) “Warrants” shall be deemed to include the Firm Warrants and the Option Warrants; (iii) “Warrant Shares” shall be deemed to refer to the shares of Common Stock issuable upon exercise of the Warrants; and (iv) “Securities” shall be deemed to include the Shares, the Optional Shares are collectively called Warrants and the “Offered Warrant Shares.” . R▇▇▇▇▇ & R▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act is acting as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered SharesSecurities. To In consideration of the extent there are no additional underwriters listed on Schedule Amutual agreements contained herein and of the interests of the parties in the transactions contemplated hereby, the term “Representatives” parties hereto agree as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basefollows:

Introductory. MEI Pharma, Inc.National Storage Affiliates Trust, a Delaware corporation Maryland real estate investment trust (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 4,500,000 common shares of its common stockbeneficial interest, par value $0.00000002 0.01 per share (the “Shares”)) of the Company. The 28,125,000 4,500,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 675,000 Shares as provided in Section 2. The additional 4,218,750 675,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” Jefferies LLC (“Jefferies”) and ▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, Co. LLC (“▇▇▇▇▇▇ Fargo▇▇▇▇▇▇▇”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3S‑3, File No. 333-217645333‑211570, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseto

Introductory. MEI PharmaAlphatec Holdings, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 8,000,000 shares of its common stock, par value $0.00000002 0.0001 per share (the “Shares”); and the stockholder of the Company named in Schedule B (the “Selling Stockholder”) proposes to sell to the Underwriters an aggregate of 8,000,000 Shares. The 28,125,000 8,000,000 Shares to be sold by the Company are called referred to as the “Firm Primary Shares” and the 8,000,000 Shares to be sold by the Selling Stockholder are referred to as the “Firm Secondary Shares” and collectively are referred to as the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 1,200,000 Shares and the Selling Stockholder has granted to the Underwriters an option to purchase up to an additional 1,200,000 Shares, all as provided in Section 2. The additional 4,218,750 1,200,000 Shares to be sold by the Company pursuant to such option are referred to as the “Optional Primary Shares” and the additional 1,200,000 Shares to be sold by the Selling Stockholder pursuant to such option are referred to as the “Optional Secondary Shares” and collectively called are referred to as the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ Jefferies & Company, Incorporated Inc. (“StifelJefferies”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives the representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645164891), including which contains a form of prospectus and has prepared a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under Act or the Securities Exchange Act in connection with the offer of 1934, as amended, and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basethe

Introductory. MEI Pharma, 5▇.▇▇▇ Inc., a Delaware corporation company incorporated in the Cayman Islands with limited liability (the “Company”), proposes agrees with the several Underwriters named in Schedule A hereto (the “Underwriters”) to issue and sell to the several underwriters Underwriters 4,000,000 American depositary shares (“ADSs”), each ADS representing two class A ordinary shares of the Company at par value US$0.00001 per share (“Ordinary Shares”), and certain shareholders of the Company named in Schedule A B hereto (the “Selling Shareholders”), agree with the Underwriters”) an , subject to the terms and conditions stated herein, to issue and sell to the Underwriters 4,000,000 ADSs (the aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares 8,000,000 ADSs to be sold by the Company are called and the Selling Shareholders being hereinafter collectively referred to as the “Firm Shares.” In addition, the Securities”). The Company has granted also agrees to issue and sell to the Underwriters Underwriters, at the option of the Underwriters, an option to purchase aggregate of up to an 1,200,000 additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called ADSs (the “Optional Shares.” Securities”). The Firm Shares and, if Securities and to the extent such option is exercised, the Optional Shares Securities, in each case including the underlying Ordinary Shares, are herein collectively called the “Offered Shares.” Securities”. The ADSs purchased by the Underwriters pursuant to this Agreement by the Underwriters will be issued pursuant to a deposit agreement dated October 31, 2013 (the “Deposit Agreement”) entered into among the Company, Citibank N.A., as depositary (the “Depositary”), and holders from time to time of the ADSs. M▇▇▇▇▇▇, ▇▇▇ S▇▇▇▇▇▇ & CompanyCo. International plc, Incorporated Credit Suisse Securities (“Stifel”USA) LLC and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to Citigroup Global Markets Inc. shall act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, A▇▇▇▇-▇▇▇▇▇▇▇▇ Energy Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 2,500,000 shares (the “Firm Shares”) of its common stockCommon Stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 375,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Shares, are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have . RBC Capital Markets Corporation has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To As more fully described in the extent there are no additional underwriters listed on Schedule ARegistration Statement (as defined below), the term Company has agreed to purchase all of the outstanding capital stock of DLS Drilling, Logistics & Services Corporation (“RepresentativesDLS”), pursuant to a stock purchase agreement dated April 27, 2006. The acquisition by the Company of all of the outstanding capital stock of DLS is referred to herein as the “Acquisition.” With respect to the representations, warranties and agreements made by the Company in this Agreement concerning its subsidiaries, such representations, warranties and agreements shall be deemed to include DLS. In connection with the Acquisition, the Company will (i) offer and sell the Securities contemplated by this Agreement; (ii) offer and sell the Notes as used herein shall mean youdefined in the purchase agreement dated , as Underwriters2006 between the Company, the Guarantors and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared Initial Purchasers named therein; and filed with the Securities and Exchange Commission (iii) enter into an amendment of its $25.0 million senior secured credit facility (the “CommissionBank Credit Facility”). These transactions (but not including the offering of Securities contemplated by this Agreement and the Registration Statement) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (are collectively referred to herein as the “Base ProspectusTransactions.”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.(a) Semiconductor Manufacturing International Corporation, a Delaware corporation Cayman Islands company limited by shares (the “"Company”"), proposes to: issue and sell to the several U.S. Underwriters named in Schedule A hereto ("U.S. Underwriters") . American Depositary Shares ("ADSs") and the shareholders listed in Schedule B hereto ("Selling Shareholders") propose severally to sell to the U.S. Underwriters an aggregate of . ADSs (together with the ADSs being sold by the Company, "U.S. Firm Securities in ADS form"), each ADS representing 50 of the Company's ordinary shares, par value US$0.0004 per share ("Securities"), all or part of which may be delivered in ordinary form at the U.S. Underwriters' election as hereinafter provided ("U.S. Offering"), and (b) the Company proposes to issue and sell to the several underwriters International Underwriters named in Schedule C hereto ("International Underwriters") . ADSs and the Selling Shareholders propose severally to sell to the International Underwriters an aggregate of . ADSs ("International Firm Securities in ADS form") each ADS representing 50 Securities, all or part of which may be delivered in ordinary form at the International Underwriters' election as hereinafter provided ("International Offering"). The U.S. Firm Securities in ADS form and any Securities delivered in lieu thereof as herein provided are hereinafter called the "U.S. Firm Securities" The International Firm Securities in ADS form and any Securities delivered in lieu thereof as herein provided are hereinafter called the "International Firm Securities". As more fully described in the Prospectus (as defined herein) under the heading "Underwriting," as part of the offering contemplated by this Agreement, Deutsche Bank Securities Inc., in its capacity as designated underwriter, ("Designated Underwriter") has agreed to reserve for the benefit of the Company's directors, officers, employees and other parties associated with the Company (collectively, "Participants") a portion of Firm Securities (as defined herein) allocated to it under this Agreement of up to 5,151,520 ADSs (the "Directed Shares" and such sale, the "Directed Share Program"). Any Directed Shares not subscribed for by the end of the business day on which this Agreement is executed will be offered to the public by the Designated Underwriter as set forth in the Prospectus. It is understood that, subject to the conditions hereinafter stated: (a) . shares of U.S. Firm Securities will be sold to the several U.S. Underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) hereto in connection with the offering and sale of such U.S. Firm Securities in the Offered SharesUnited States and Canada to United States and Canadian Persons (as such terms are defined in the Agreement Between U.S. Underwriters and International Underwriters of even date herewith) and (b) . To shares of International Firm Securities will be sold to the extent there are no additional underwriters listed on several International Underwriters named in Schedule AC hereto in connection with the offering and sale of such International Firm Securities outside the United States and Canada to persons other than United States and Canadian Persons. The ADSs purchased by the Underwriters will be evidenced by American Depositary Receipts ("ADRs") to be issued pursuant to a Deposit Agreement to be dated as of March [18], 2004 (the term “Representatives” as used herein shall mean you"Deposit Agreement"), to be entered into among the Company, JPMorgan Chase Bank, as depositary (the "Depositary"), and all holders from time to time of the ADRs. Credit Suisse First Boston LLC and Deutsche Bank Securities Inc. shall act as the representatives (the "U.S. Representatives") of the several U.S. Underwriters, and Credit Suisse First Boston (Hong Kong) Limited and Deutsche Bank AG, Hong Kong Branch shall act as the term “representatives (the "International Representatives" and, together with the U.S. Representatives, the "Representatives") of the several International Underwriters” shall mean either . The U.S. Underwriters and the singular or International Underwriters are hereinafter collectively referred to as the plural"Underwriters". In addition, as set forth below the context requiresSelling Shareholders propose to sell: (a) to the U.S. Underwriters, at the option of the U.S. Underwriters, an aggregate of not more than . additional ADSs ("U.S. Optional Securities in ADS form"), all or part of which may be delivered in ordinary form at the U.S. Underwriters' election as hereinafter provided, and (b) to the International Underwriters, at the option of the International Underwriters, an aggregate of not more than . additional ADSs ("International Optional Securities in ADS form"), all or part of which may be delivered in ordinary form at the International Underwriters' election as hereinafter provided. The U.S. Optional Securities in ADS form and any Securities delivered in ordinary form in lieu thereof as herein provided are hereinafter called the "U.S. Optional Securities". The International Optional Securities in ADSs form and any Securities delivered in ordinary form in lieu thereof as herein provided are hereinafter called the "International Optional Securities". The U.S. Firm Securities and the U.S. Optional Securities are hereinafter called the "U.S. Securities"; the International Firm Securities and the International Optional Securities are hereinafter called the "International Securities"; the U.S. Firm Securities and the International Firm Securities are hereinafter called the "Firm Securities"; the U.S. Optional Securities and the International Optional Securities are hereinafter called the "Optional Securities". The U.S. Securities and the International Securities are collectively referred to as the "Offered Securities", and the Offered Securities and the Hong Kong Securities (as defined below), are collectively referred to as the "Global Offered Securities". Whenever computations are contemplated herein that involve both numbers of ADSs and numbers of Securities in ordinary form, they shall be made on a consistent basis, by first converting the number of ADSs into the number of Securities in ordinary form they represent. It is further understood that the Company has prepared entered into an underwriting agreement, dated March 5, 2004 (the "Hong Kong Underwriting Agreement"), with respect to the underwriting of the offering by the Company of an aggregate of 257,576,000 Securities, subject to adjustment (the "Hong Kong Securities"), to the public in Hong Kong by certain underwriters in Hong Kong (the "Hong Kong Underwriters") for whom Credit Suisse First Boston (Hong Kong) Limited and filed Deutsche Bank AG, Hong Kong Branch, are acting as representatives (the "Hong Kong Representatives") pursuant to a Hong Kong prospectus dated March 8, 2004, (the "Hong Kong Prospectus"). The offering of the Hong Kong Securities by the Company is referred to herein as the "Hong Kong Public Offering". The Hong Kong Prospectus is being used in connection with the Hong Kong Public Offering pursuant to the Hong Kong Underwriting Agreement and contains substantially the same information included in the U.S. Prospectus and International Offering Circular (each as defined below) and certain supplemental pages. The Hong Kong Public Offering, the U.S. Offering and the International Offering are collectively referred to herein as the "Global Offering". Anything herein or therein to the contrary notwithstanding, the respective closings under this Agreement and the Hong Kong Underwriting Agreement are hereby made expressly conditional on one another. It is understood that the Company is not obligated to sell, and the Underwriters are not obligated to purchase, any Firm Securities unless the Hong Kong Underwriting Agreement shall have become unconditional in all respects in accordance with its terms and Exchange Commission shall not have been terminated. To provide for the coordination of their activities, the U.S. Underwriters, the Hong Kong Underwriters and the International Underwriters have entered into an agreement among U.S. Underwriters, Hong Kong Underwriters and International Underwriters which permits them, among other things, to sell the Offered Securities to each other for purposes of resale, and provides for certain other matters (the “Commission”) a shelf registration statement on Form S-3, File No"Intersyndicate Agreement"). 333-217645, including a base prospectus (the “Base Prospectus”) Three forms of offering documents are to be used in connection with the public offering and sale of ADSs under this Agreement: (i) The U.S. Prospectus (as defined herein) which relates to the Offered SharesU.S. Offering, (ii) the Japanese Prospectus (as defined herein) relating to a public offering without listing of the Securities in Japan ("Japanese POWL") as part of the International Offering and (iii) an offering circular relating to the International Offering excluding the portion of the Global Offering relating to the Japanese POWL ("International Offering Circular"). Such registration statement, The U.S. Prospectus will be substantially identical to the International Offering Circular except for substitute cover pages and a limited number of changes in the Prospectuses. The Japanese Prospectus is prepared in the Japanese language in accordance with the Securities and Exchange Law of Japan. The Japanese Final Prospectus (as amended, including the financial statements, exhibits and schedules theretodefined herein) is prepared, in principle, based on the form information included in which it became effective under the Securities Act of 1933U.S. Prospectus, as amended, International Offering Circular and the rules Hong Kong Prospectus with such omissions and regulations promulgated thereunder (collectivelyadditions as appropriate for the purpose of the Japanese POWL. The U.S. Prospectus, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares International Offering Circular and the offering thereof (Japanese Prospectus are collectively referred to as the “Preliminary Prospectus Supplement”), together with the Base"Prospectuses."

Introductory. MEI PharmaJinkoSolar Holding Co., Inc.Ltd., a Delaware corporation an exempted company incorporated under the laws of the Cayman Islands (the “Company”), proposes agrees with Credit Suisse Securities (USA) LLC and Barclays Capital Inc. (together, the “Managers” and each a “Manager”), to issue and sell from time to time through the several underwriters named in Schedule A Managers, as sales agents, acting severally and not jointly, American Depositary Shares (the “UnderwritersADSs” and each an “ADS”) an aggregate of 28,125,000 ), each representing four ordinary shares of its common stock, par value $0.00000002 per share US$0.00002 each of the Company (the “Ordinary Shares”), having an aggregate offering price of up to US$[100,000,000] on the terms set forth herein. The 28,125,000 Shares ADSs are to be sold issued pursuant to the Deposit Agreement. Each Manager agrees that whenever the Company determines to sell the ADSs through the Manager, acting as sales agent, severally and not jointly with the other Manager, the Manager will send to the Company a notice, which may be in the form of an email sent to the email addresses of the Company as set forth in Section 8 hereof (a “Transaction Notice”), confirming the agreed terms of such proposed transaction and the Company shall promptly indicate its acceptance thereof by countersigning and returning such Transaction Notice by the Company are called the “Firm Shares.” In addition, the Company has granted means set forth in Section 8 hereof or by sending an email confirming acceptance of such Transaction Notice to the Underwriters an option to purchase up to an additional 4,218,750 Shares email addresses of the relevant Manager as provided set forth in Section 2. The additional 4,218,750 Shares to 8 hereof (provided that, such email confirmation (i) may only be sold given by the Company pursuant to such option are collectively called following authorized person of the “Optional Shares.” The Firm Shares andCompany, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇namely: X▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives Chairman of the several Underwriters board of directors of the Company); and (ii) must contain the same information that the Transaction Notice would have contained), in each case in accordance with Section 3 of this Agreement. Each Manager acting as sales agent shall provide such capacityconfirmation in accordance with Section 3(h) of this Agreement. The Company agrees that whenever it determines to sell the ADSs directly to each Manager, the as principal, it will enter into a separate agreement (a “RepresentativesTerms Agreement”) in connection with form and substance satisfactory to the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, Manager and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed relating to such sale in accordance with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale Section 3 of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementthis Agreement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaPhytera, Inc., a Delaware corporation (the “"Company”"), ------------- proposes to issue and sell sell, pursuant to the terms of this Agreement, to the several U.S. underwriters named in Schedule A hereto (the “"U.S. Underwriters”) ," or, each, a "U.S. Underwriter"), an aggregate of 28,125,000 ________ shares of its common stockCommon Stock, $0.01 par value $0.00000002 per share (the “Shares”"Common Stock"), of the Company. The 28,125,000 Shares aggregate of _________ shares so proposed to be sold by is hereinafter referred to as the "U.S. Firm Stock". The Company are called the “Firm Shares.” In addition, the Company has granted also proposes to sell to the Underwriters an option to purchase U.S. Underwriters, upon the terms and conditions set forth in Section 3 hereof, up to an additional 4,218,750 Shares as provided _________ shares of Common Stock (the "U.S. Optional Stock") solely to cover over-allotments in Section 2connection with the sale of the U.S. Firm Stock. The additional 4,218,750 Shares U.S. Firm Stock and the U.S. Optional Stock are hereinafter collectively referred to be sold by as the Company pursuant to such option are collectively called the “Optional Shares"U.S. Stock.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” " ▇▇ ▇▇▇▇▇ Securities Corporation ("▇▇ ▇▇▇▇▇"), Carnegie Inc. and Banc Boston ▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇▇▇▇ Fargo SecuritiesInc. are acting as representatives of the several U.S. Underwriters and in such capacity are hereinafter referred to as the "U.S. Representatives." It is understood that the Company is concurrently entering into an agreement dated the date hereof (the "European Underwriting Agreement") providing for the sale to the several underwriters named in Schedule B hereto (the "European Managers," or, LLC each, a "European Manager"), of an aggregate of ___________ shares of Common Stock of the Company. The aggregate of __________ shares so proposed to be sold is hereinafter referred to as the "European Firm Stock." The Company also proposes to sell to the European Managers, upon the terms and conditions set forth in Section 3 thereof, up to an additional _______ shares of Common Stock (“the "European Optional Stock"). The European Firm Stock and the European Optional Stock are hereinafter collectively referred to as the "European Stock." ▇▇ ▇▇▇▇▇ Fargo”) have agreed to act International L.P., Carnegie Bank A/S and BancBoston ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇▇ International Ltd. are acting as representatives of the several European Managers and in such capacity are hereinafter referred to as the "European Representatives." The respective closings under this Agreement and the European Underwriting Agreement are hereby expressly made conditional upon one another. The U.S. Underwriters and the European Managers are hereinafter collectively referred to as the "Underwriters" and the U.S. Stock and the European Stock are hereinafter collectively referred to as the "Stock." The Company understands that the U.S. Underwriters and the European Managers will concurrently enter into an Intersyndicate Agreement of even date herewith (the "Intersyndicate Agreement") providing for the coordination of certain transactions among the Underwriters under the direction of ▇▇ ▇▇▇▇▇ (in such capacity, the “Representatives”"Global Coordinator") in connection with and that, pursuant thereto and subject to the offering and sale conditions set forth therein, the European Managers may purchase from the U.S. Underwriters a portion of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, U.S. Stock and the term “Underwriters” shall mean either U.S. Underwriters may purchase from the singular or European Managers a portion of the plural, as the context requiresEuropean Stock. The Company has prepared understands that any purchases and filed with sales between the Securities European Managers and Exchange Commission (the “Commission”) U.S. Underwriters shall be governed by the Intersyndicate Agreement and shall not be governed by the terms of this Agreement or the European Underwriting Agreement. The Company understands that the U.S. Underwriters propose to make a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, U.S. Stock as amended, including soon as the financial statements, exhibits U.S. Representatives deem advisable after this Agreement has been executed and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementdelivered.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Axovant Sciences Ltd., a Delaware corporation company incorporated and organized under the laws of Bermuda (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its 26,666,667 common stockshares, par value $0.00000002 0.00001 per common share (the “Shares”). The 28,125,000 26,666,667 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 4,000,000 Shares as provided in Section 2. The additional 4,218,750 4,000,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated LLC (“StifelJefferies”) and ▇▇▇▇▇ Fargo Guggenheim Securities, LLC (“▇▇▇▇▇ FargoGuggenheim”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645215387, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16March 13, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseBase Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other prospectus

Introductory. MEI Pharma, Inc.Abraxas Petroleum Corporation, a Delaware Nevada corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (together, the “Underwriters”) ), an aggregate of 28,125,000 10,000,000 shares of its common stockstock (the “Firm Shares”), par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 1,500,000 shares of Common Stock (the “Optional Shares”), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇▇▇ Inc., ▇▇Canaccord Genuity Inc. and ▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇. ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) & Co. Incorporated have agreed to act as representatives of the several Underwriters (in such capacity, capacity is hereinafter referred to as the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645188110), including a base prospectus dated June 6, 2013 (the “Base Prospectus”) ), to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A 430B or 430B Rule 430C (the “Rule 430 Information”) under the Securities Act or the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called referred to as the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale The prospectus supplement, dated as of the Offered Shares is called the “Rule 462(b) Registration StatementJune 12,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaAmerican Capital Strategies, Inc.Ltd., a Delaware corporation (the “Company”), proposes to issue confirms its agreement with the Representatives (as defined below) and sell to each of the several underwriters other Underwriters named in Schedule A attached hereto and made a part hereof (collectively, the “Underwriters”) an with respect to (a) the sale by the Company and purchase by the Underwriters, acting severally and not jointly, of their respective portions of $ • aggregate principal amount of 28,125,000 shares of its common stock, par value $0.00000002 per share the Company’s • Notes due • (the “SharesSecurities”). The 28,125,000 Shares to Securities will be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up issued pursuant to an additional 4,218,750 Shares Indenture dated as provided in Section 2. The additional 4,218,750 Shares to be sold of April 26, 2007, by and between the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) as issuer, and ▇▇▇▇▇ Fargo SecuritiesBank, LLC National Association, as trustee (the “▇▇▇▇▇ FargoTrustee”) ), as supplemented by a First Supplemental Indenture thereto to be dated as of • (collectively, the “Indenture”). [Underwriter] and [Underwriter] have agreed to act as representatives of each of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed with the United States Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) pursuant to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”) and the Investment Company Act of 1940, as amended, and the rules and regulations promulgated thereunder (the “Investment Company Act”), a registration statement on Form N-2 for the offer and sale of an aggregate amount of $5,000,000,000 of securities (File No. 333-142398), which registration statement became effective on June 5, 2007, a copy of which has heretofore been delivered to you. The Company proposes to file with the Commission pursuant to Rule 497 under the Securities Act, a supplement, dated as of •, to the final prospectus dated as of June 5, 2007, relating to the Securities and the method of distribution thereof and has previously advised you of all further information (financial and other) with respect to the Securities set forth therein. Such registration statement, including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof the exhibits thereto, as amended at the date hereof, is hereinafter called the “Registration Statement”; such prospectus, in the form in which it was included in the Registration Statement at the time of effectiveness it was declared effective, is hereinafter called the “Basic Prospectus”; such supplement to the Basic Prospectus, in the form in which it will be filed with the Commission pursuant to Rule 430A or 430B 497 under the Securities Act, is hereinafter called the “Registration StatementProspectus Supplement” and the Basic Prospectus and Prospectus Supplement together are hereinafter called the “Prospectus.” Any registration statement The Prospectus, subject to completion, used in connection with a public offering is called a “Preliminary Prospectus,” and any reference to the “most recent Preliminary Prospectus” shall be deemed to refer to the Preliminary Prospectus most recently filed by the Company pursuant to Rule 462(b) 497 under the Securities Act as of the date hereof. All references in connection this underwriting agreement (this “Agreement”) to the Registration Statement, the Preliminary Prospectus, the Prospectus, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed, as applicable, with the offer Commission pursuant to its Electronic Data Gathering, Analysis and sale of the Offered Shares is called the Retrieval System (“Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement▇▇▇▇▇”). The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together Company hereby confirms its agreements with the BaseUnderwriters as follows:

Introductory. MEI PharmaLomak Petroleum, Inc., a Delaware corporation (the “"Company”), ") proposes to issue and sell sell, pursuant to the terms of this Agreement, to the several underwriters Underwriters named in Schedule A hereto (the “"Underwriters”" which term also shall include any underwriter substituted as hereinafter provided in Section 11) an aggregate of 28,125,000 4,000,000 shares of its common stockCommon Stock, par value $0.00000002 .01 per share (the “Shares”)"Common Stock") of the Company. The 28,125,000 Shares aggregate of 4,000,000 shares so proposed to be sold by the Company are is herein called the “"Firm Shares.” In addition, the Stock". The Company has granted also proposes to sell severally to the Underwriters Underwriters, on a pro rata basis, at the option of the Underwriters, an option to purchase up to an aggregate of not more than 600,000 additional 4,218,750 Shares shares of Common Stock as provided in Section 23 of this Agreement. The additional 4,218,750 Shares aggregate of 600,000 shares so proposed to be sold by is herein called the Company pursuant to such option "Optional Stock". The Firm Stock and the Optional Stock are collectively called referred to herein as the “Optional Shares.” The Firm Shares and"Stock". Morg▇▇ ▇▇▇n▇▇▇ & ▇o. Incorporated, if and to the extent such option is exercisedPaineWebber Incorporated, the Optional Shares are collectively called the “Offered Shares.” Smit▇ ▇▇▇▇▇▇ ▇▇▇., ▇A.G. ▇▇▇▇▇▇▇ & Company▇ons, Incorporated (“Stifel”) Inc. and ▇McDo▇▇▇▇ Fargo & ▇ompany Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act Inc. are acting as representatives of the several Underwriters (and in such capacitycapacity are hereinafter referred to as the "Representatives". It is understood by all parties that the Company is concurrently entering into an agreement, dated the date hereof (the "Debt Underwriting Agreement") providing for the sale by the Company of $100,000,000 principal amount of its __% Senior Subordinated Notes due 2007 to Chase Securities Inc., NationsBanc Capital Markets, Inc., Bear, Stea▇▇▇ & ▇o. Inc. and Credit Suisse First Boston Corporation, as underwriters. Before the purchase and public offering of the Stock by the several Underwriters, the “Company and the Representatives”) in connection with the offering and sale , 2 acting on behalf of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as several Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, enter into an agreement substantially in the form of Exhibit A hereto (the "Pricing Agreement"). The Pricing Agreement may take the form of an exchange of any standard form of written telecommunication between the Company and the Representatives and shall specify such applicable information as is indicated in which it became effective under Exhibit A hereto. The offering of the Securities Act of 1933Stock will be governed by this Agreement, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BasePricing Agreement.

Introductory. MEI Pharma, Inc.Zuoan Fashion Limited, a Delaware corporation Cayman Islands company with limited liability (the “Company”), proposes and the selling shareholders named in Schedule B hereto (the “Selling Shareholders”) propose to issue and sell sell, pursuant to the terms of this Agreement, to the several underwriters named in Schedule A hereto (the “Underwriters,” or, each, an “Underwriter”) ), an aggregate of 28,125,000 6,900,000 American Depositary Shares (“ADSs”), each ADS representing four ordinary shares of its common stockthe Company, par value $0.00000002 US$0.00025 per share (the “Common Shares”). The 28,125,000 Shares aggregate of 6,900,000 ADSs so proposed to be sold by the Company are called is hereinafter referred to as the “Firm Shares.” In addition, the Company has granted The Selling Shareholders listed in Schedule B hereto also propose to sell to the Underwriters an option to purchase Underwriters, upon the terms and conditions set forth in Section 3 hereof, up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called 1,035,000 ADSs (the “Optional Shares.” ”). The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & and Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act is acting as representatives representative of the several Underwriters (and in such capacity, capacity is hereinafter referred to as the “Representatives”) in connection with Representative.” Unless the offering and sale of context otherwise requires, references to the Offered “Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, constitute references both to the Common Shares and to the term ADSs (and to the Common Shares represented by such ADSs). All references to “UnderwritersUS dollars” shall mean either the singular or the plural, as the context requires“$” herein are to United States dollars. The Company has prepared and filed with ADSs purchased by the Securities and Exchange Commission Underwriters will be evidenced by American Depositary Receipts (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base ProspectusADRs”) to be used in connection with the public offering and sale issued pursuant to a Deposit Agreement dated as of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder 2010 (collectively, the “Securities ActDeposit Agreement”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at entered into among the time of effectiveness pursuant to Rule 430A or 430B under the Securities ActCompany, is called the “Registration Statement.” Any registration statement filed by the Deutsche Bank Trust Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16Americas, 2019 describing the Offered Shares and the offering thereof as depositary (the “Preliminary Prospectus SupplementDepositary”), together with the Baseand all holders and beneficial owners from time to time of ADSs.

Introductory. MEI Pharma, Inc.Gemini Genomics plc, a Delaware corporation public limited company organized under the laws of England and Wales (the “"Company”"), proposes to issue and sell sell, pursuant to the terms of this Agreement, to the several underwriters named in Schedule A hereto (the “"Underwriters”) ," or, each, an "Underwriter"), an aggregate of 28,125,000 6,000,000 American depositary shares ("ADSs") representing 12,000,000 of its common stockthe Company's Ordinary Shares, par 5p nominal value $0.00000002 per share (the “"Ordinary Shares”"). The 28,125,000 Shares aggregate of 6,000,000 ADSs so proposed to be sold are hereinafter referred to as the "Firm ADSs" and the Ordinary Shares represented by the Company Firm ADSs are called hereinafter referred to as the “"Firm Shares.” In addition, the ". The Company has granted also proposes to sell to the Underwriters an option to purchase Underwriters, upon the terms and conditions set forth in Section 3 hereof, up to an additional 4,218,750 900,000 ADSs (the "Optional ADSs") representing 1,800,000 Ordinary Shares as provided in Section 2(the "Optional Shares"). The additional 4,218,750 Shares Firm ADSs and the Optional ADSs are hereinafter collectively referred to be sold by as the Company pursuant to such option are collectively called "ADSs", the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are hereinafter collectively called referred to as the “Offered "Shares.” " and references to ADSs include the ADRs (as defined below) evidencing such ADSs, in each case, unless the context otherwise requires. ▇▇ ▇▇▇▇▇ Securities Corporation ("▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”") and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act Securities Inc. are acting as representatives of the several Underwriters (and in such capacitycapacity are hereinafter referred to as the "Representatives." The ADSs, the “Representatives”) evidenced by American Depositary Receipts ("ADRs"), will be issued in connection accordance with the offering and sale Deposit Agreement (the "Deposit Agreement"), among the Company, The Bank of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean youNew York, as Underwritersdepositary (the "Depositary"), and the term “Underwriters” shall mean either holders and beneficial owners from time to time of ADRs issued thereunder. Each ADS will represent __ Ordinary Shares deposited pursuant to the singular or the pluralDeposit Agreement and delivered to The Bank of New York, London office, as custodian for the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration StatementDepositary.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Caribou Holding Company Limited, a Delaware corporation Cayman Island company (the “CompanySelling Shareholder”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 5,150,000 shares of its common stock, par value $0.00000002 0.01 per share (the “Shares”) of Caribou Coffee Company Inc., a Minnesota corporation (the “Company”). The 28,125,000 5,150,000 Shares to be sold by the Company Selling Shareholder are called the “Firm Shares.” In addition, the Company Selling Shareholder has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 772,245 Shares, all as provided in Section 2. The additional 4,218,750 772,245 Shares to be sold by the Company Selling Shareholder pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Inc. (“StifelJefferies”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives Representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645170634), including and has prepared a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A 430B under the Securities Act or 430B the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” Such prospectus, in the form first used by the Underwriters to confirm sales of the Offered Shares or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act, is called the “Registration StatementProspectus.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16August 15, 2019 2011 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”)thereof, together with the BaseBase Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other preliminary prospectus supplement to the Base Prospectus that describes the Offered

Introductory. MEI PharmaUNITED FINANCIAL MORTGAGE CORP., Inc., a Delaware an Illinois corporation (the “"Company”"), proposes to issue and sell _____________ shares of its authorized but unissued Common Stock, no par value (the "Firm Common Stock") to you, or if there be any so named, to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an aggregate of 28,125,000 shares of its common stock"), par value $0.00000002 per share (the “Shares”)for whom you are acting as representative. The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to you or to the Underwriters Underwriters, as the case may be, an option to purchase up to an aggregate of ________ additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇" In addition, ▇▇▇the Company proposes to sell to ▇▇▇▇▇ & CompanyFinancial Services, Incorporated Inc. warrants (“Stifel”"Underwriter's Warrants") to purchase _________ (up-to __________ if the over-allotment option is exercised) pursuant to an Underwriter's Warrant Purchase Agreement between the Company and ▇▇▇▇▇ Fargo SecuritiesFinancial Services, LLC (“▇▇▇▇▇ Fargo”) Inc. You have agreed to act as representatives of advised the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular Company that you or the pluralUnderwriters, as the context requirescase may be, propose to make a public offering of their respective portions of the Common Shares on the effective date of the registration statement hereinafter referred to, or as soon thereafter as in your judgment is advisable. The Company has prepared and filed hereby confirms its agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statementCommon Shares by you or the Underwriters, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933case may be, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementfollows.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaTrustreet Properties, Inc., a Delaware corporation Maryland corporation, (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 7,000,000 shares (the “Firm Shares”) of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 1,050,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ”. Banc of America Securities LLC (“BAS”) and ▇▇▇▇▇▇▇ ▇▇▇▇▇ & Co., ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC & ▇▇▇▇▇ Incorporated (“▇▇▇▇▇▇▇ Fargo▇▇▇▇▇”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters Underwriters listed on Schedule AA other than you, the term “Representatives” terms Representatives and Underwriters as used herein shall mean you, as Underwriters, . The terms Representatives and the term “Underwriters” Underwriters shall mean either the singular or the plural, plural as the context requires. The Company has prepared was formed as a result of (a) the merger on February 25, 2005 of CNL Restaurant Properties, Inc., a Maryland corporation, (“CNLRP”), with and filed with the Securities and Exchange Commission into U.S. Restaurant Properties, Inc., a Maryland corporation (“USRP”) (the “CommissionCNLRP Merger”) a shelf registration statement on Form S-3), File No. 333-217645and pursuant to which USRP was the surviving corporation and changed its name to “Trustreet Properties, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale Inc.” following consummation of the Offered Shares. Such registration statementCNLRP Merger and (b) the mergers on February 25, 2005 of separate newly-formed wholly owned Subsidiaries (as amendeddefined below) of USRP with and into each of the income funds listed in Schedule B, including the financial statementseach a Florida limited partnership (each, exhibits and schedules theretoan “Income Fund” and, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities ActIncome Funds”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”)Income Fund Mergers” and, together with the BaseCNLRP Merger, the “Mergers”), pursuant to which each Income Fund became a wholly owned Subsidiary of the Company.

Introductory. MEI Pharma, Inc.Wave Life Sciences Ltd. (Company Registration Number: 201218209G), a Delaware corporation company incorporated under the laws of the Republic of Singapore (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) (i) an aggregate of 28,125,000 shares 23,125,001 of its common stockordinary shares, no par value $0.00000002 per share (the “Shares”) and (ii) pre-funded warrants, substantially in the form of Exhibit C hereto, to purchase up to an aggregate of 1,875,023 Shares (the “Pre-Funded Warrants”). The 28,125,000 23,125,001 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 3,750,000 Shares as provided in Section 2. The additional 4,218,750 3,750,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” The Shares issuable upon exercise of the Pre-Funded Warrants are referred to herein as the “Warrant Shares.” The Offered Shares, the Pre-Funded Warrants and the Warrant Shares are collectively referred to herein as the “Offered Securities.” ▇.▇▇▇▇▇, ▇▇. ▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) Securities LLC and ▇▇▇▇▇ Fargo Securities, Leerink Partners LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645263251, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered SharesSecurities. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares Securities is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseRegistration

Introductory. MEI PharmaQTS Realty Trust, Inc., a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 5,500,000 shares of its Class A common stock, par value $0.00000002 0.01 per share (the “Shares”). The 28,125,000 5,500,000 Shares to be issued and sold by the Company are being hereinafter called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 825,000 Shares, as provided in Section 2. The additional 4,218,750 825,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” M▇▇▇▇▇▇ Lynch, Pierce, F▇▇▇▇▇ & S▇▇▇▇ Incorporated (“Merrill”), J.▇. ▇▇▇▇▇▇ Securities LLC (“J.▇. ▇▇▇▇▇▇”) and S▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a an automatic shelf registration statement on Form S-3, File No. 333-217645210425, including a base prospectus dated March 28, 2016 (including the documents incorporated or deemed to be incorporated by reference therein prior to the time of the execution of this Agreement pursuant to Item 12 of Form S-3 under the Securities Act (as defined below) the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein pursuant to Item 12 of Form S-3 and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Such Registration Statement became effective upon filing under Rule 462(b462(e) under of the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration StatementAct. The preliminary prospectus supplement dated December 16March 28, 2019 2016 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseBase Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other prospectus supplement to the Base Prospectus in preliminary form that describes the Offered Shares and the offering thereof and is used prior to the filing of the Prospectus (as defined below), together with the Base Prospectus, is called a “preliminary prospectus.”

Introductory. MEI PharmaAmerican Capital Strategies, Inc.Ltd., a Delaware corporation (the “"Company”"), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇Citigroup Global Markets Inc., ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated and Wachovia Capital Markets, LLC, each of them acting either as a principal or as an agent for one of its affiliates (collectively, the "Forward Sellers"), at the request of the Company in connection with the "Forward Agreements" (as defined below) attached hereto as Exhibit A, confirm their respective agreements with the Representatives (as defined below) and each of the other Underwriters named in Schedule A attached hereto and made a part hereof (collectively, the "Underwriters") with respect to (a) the sale by the Company and the Forward Sellers (including the possible issuance and sale by the Company of Common Stock (as defined below) to the Underwriters pursuant to Section 12(a) hereof), and purchase by the Underwriters, acting severally and not jointly, of their respective portions of 20,000,000 shares of Common Stock, including the Borrowed Shares (as defined below) (the "Firm Shares") and all or any part of 3,000,000 additional shares of Common Stock (the "Option Shares") as provided in Section 3(b) hereof (the Firm Shares and Option Shares collectively being referred to as the "Shares"), and (b) the grant by the Company to the Underwriters of the option described in Section 3(b) hereof to purchase all or any part of the Option Shares to cover over-allotments, if any. "Common Stock" shall refer to the $0.01 par value per share of common stock of the Company. "Forward Agreements" shall refer to the letter agreements, Incorporated which relate to the forward sale by the Company of a number of shares of Common Stock equal to the number of shares of Common Stock to be borrowed and sold by the Forward Sellers pursuant to this Agreement (“Stifel”the "Borrowed Shares"), dated the date hereof and entered into by and between the following: (a) the Company and Citigroup Global Markets, Inc., (b) the Company and ▇▇▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”International and (c) the Company and Wachovia Bank, N.A. Citigroup Global Markets Inc, ▇▇▇▇▇▇▇ ▇▇▇▇▇ International and Wachovia Bank, N.A., are hereafter referred to as the "Forward Counterparties." Of the Firm Shares, 15,000,000 shares (plus any additional shares of Common Stock issued and sold by the Company pursuant to Section 12(a) hereof), will be issued and sold to the Underwriters by the Company (the "Company Firm Shares") and 5,000,000 shares (subject to reduction for any shares issued and sold by the Company pursuant to Section 12(a) hereof) will be sold to the Underwriters by the Forward Sellers (the "Forward Seller Firm Shares"). Citigroup Global Markets Inc., ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated and Wachovia Capital Markets, LLC have agreed to act as representatives of each of the several Underwriters (in such capacity, the “"Representatives”") in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the United States Securities and Exchange Commission (the “"Commission”") a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) pursuant to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “"Securities Act”") and the Investment Company Act of 1940, as amended, and the rules and regulations promulgated thereunder (the "Investment Company Act"), a registration statement on Form N-2 for the offer and sale of an aggregate amount of $5,000,000,000 of securities (File No. 333-142398), which registration statement became effective on June 5, 2007, a copy of which has heretofore been delivered to you. The Company proposes to file with the Commission pursuant to Rule 497 under the Securities Act, a supplement, dated as of June 18, 2007, to the final prospectus dated as of June 5, 2007, relating to the Shares and the method of distribution thereof and has previously advised you of all further information (financial and other) with respect to the Shares set forth therein. Such registration statement, including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof the exhibits thereto, as amended at the date hereof, is hereinafter called the "Registration Statement"; such prospectus, in the form in which it was included in the Registration Statement at the time of effectiveness it was declared effective, is hereinafter called the "Basic Prospectus"; such supplement to the Basic Prospectus, in the form in which it will be filed with the Commission pursuant to Rule 430A or 430B 497 under the Securities Act, is hereinafter called the “Registration Statement"Prospectus Supplement" and the Basic Prospectus and Prospectus Supplement together are hereinafter called the "Prospectus.” Any registration statement " The Prospectus, subject to completion, used in connection with a public offering is called a "Preliminary Prospectus," any reference to the "most recent Preliminary Prospectus" shall be deemed to refer to the Preliminary Prospectus most recently filed by the Company pursuant to Rule 462(b) 497 under the Securities Act as of the date hereof. All references in connection this underwriting agreement (this "Agreement") to the Registration Statement, the Preliminary Prospectus, the Prospectus, or any amendments or supplements to any of the foregoing, shall include any copy thereof filed, as applicable, with the offer Commission pursuant to its Electronic Data Gathering, Analysis and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration StatementRetrieval System ("▇▇▇▇▇"). The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together Company hereby confirms its agreements with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.Compugen Ltd., a Delaware corporation organized under the laws of the State of Israel (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares 6,000,000 (the “Firm Shares”) of its common stockthe Company’s ordinary shares, par nominal (par) value $0.00000002 NIS 0.01 per share (the “Ordinary Shares”). The 28,125,000 respective amounts of the Firm Shares to be sold purchased by each of the Company several Underwriters are called the “Firm Shares.” set forth opposite their names on Schedule A hereto. In addition, the Company has granted proposes to grant to the Underwriters an option to purchase up to an additional 4,218,750 900,000 Ordinary Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by (the “Option Shares”) from the Company pursuant to such option are collectively called for the “Optional sole purpose of covering over-allotments in connection with the sale of the Firm Shares.” . The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered SharesSecurities.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoJefferies”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requiresSecurities. The Company has prepared and filed in conformity with the requirements of the Securities Act of 1933, as amended (the “Securities Act”), and the published rules and regulations thereunder (the “Rules”) adopted by the Securities and Exchange Commission (the “Commission”) a shelf “shelf” registration statement on Form S-3, File F-3 (No. 333-217645185910), which became effective as of January 16, 2013, including a base prospectus (the “Base Prospectus”) relating to be used in connection with the public offering Ordinary Shares and sale other securities of the Offered Shares. Such registration statement, as amended, including Company that may be sold from time to time by the financial statements, exhibits and schedules thereto, Company in the form in which it became effective under the Securities Act accordance with Rule 415 of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called and such amendments thereof as may have been required to the “date of this Agreement. Copies of such Registration Statement.” Any registration statement filed Statement (including all amendments thereof and all documents deemed incorporated by reference therein) and of the related Base Prospectus have heretofore been delivered by the Company pursuant or are otherwise available to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseyou.

Introductory. MEI Pharma, Inc.First Potomac Realty Trust, a Delaware corporation Maryland real estate investment trust (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 shares 2,500,000 of its common stockshares (the “Firm Shares”) of beneficial interest, par value $0.00000002 .001 per share (the “Common Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 375,000 Common Shares (the “Option Shares”), as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Option Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated KeyBanc Capital Markets Inc. (“StifelKCM”) and ▇▇▇▇▇ Fargo Securities), LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To The Company is the extent there are no additional underwriters listed on Schedule Asole general partner of First Potomac Realty Investment Limited Partnership (the “Operating Partnership”), the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, a Delaware limited partnership that serves as the context requiresCompany’s primary operating partnership subsidiary. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3), File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or on April 16, 2007 a registration statement on Form S-3, which was subsequently amended on August 19, 2008 and August 22, 2008 (File No. 333-142147), which contains a form of prospectus to be used in connection with the public offering and sale of the Shares (the “Base Prospectus”). Such registration statement, herein referred to as the “Registration Statement,” shall be deemed to include all information omitted therefrom in reliance upon Rules 430A or 430B under the Securities Act and all information incorporated by reference therein. The form of final prospectus relating to the Shares first filed by the Company with the Commission pursuant to Rule 424(b) under the Securities Act is herein referred to as the “Prospectus.” The Base Prospectus, as supplemented by any preliminary prospectus (including any preliminary prospectus supplement) relating to the Shares used prior to the date hereof is herein referred to as a “Preliminary Prospectus.” Any reference herein to the Registration Statement, any Preliminary Prospectus or the Prospectus or to any amendment or supplement to any of the foregoing documents shall be deemed to refer to and include any documents incorporated by reference therein and any information deemed to be a part thereof at supplements or amendments thereto, filed with the time Commission after the date of effectiveness pursuant to filing of the Prospectus under Rule 430A or 430B 424(b) under the Securities Act, is called and prior to the “Registration Statement.” Any registration statement filed termination of the offering of the Shares by the Underwriters. Each of the Company pursuant to Rule 462(b) under and the Securities Act in connection Operating Partnership hereby confirms its agreements with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Inc.The shareholders of iGATE Corporation, a Delaware Pennsylvania corporation (the “Company”), proposes named in Schedule A (collectively, the “Selling Stockholders”), severally propose to issue and sell to the several underwriters named in Schedule A B (the “Underwriters”) an aggregate of 28,125,000 4,000,000 shares of its the Company’s common stock, par value $0.00000002 0.01 per share (the “Shares”). The 28,125,000 4,000,000 Shares to be sold by the Company Selling Stockholders are collectively called the “Firm Shares.” In addition, the Company has Selling Stockholders have severally granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 598,756 Shares, with each Selling Stockholder selling up to the amount set forth opposite such Selling Stockholder’s name in Schedule A, all as provided in Section 2. The additional 4,218,750 598,756 Shares to be sold by the Company Selling Stockholders pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated Inc. (“StifelJefferies”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645162606), including and has prepared a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act or the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder (collectively, the “Exchange Act”), is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such the Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16Such prospectus, 2019 describing in the Offered Shares and form first used by the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseUnderwriters

Introductory. MEI PharmaRadiant Systems, Inc., a Delaware Georgia corporation (the “Company”), proposes to issue and sell to the several underwriters Underwriters named in on Schedule A (the “Underwriters”) an aggregate of 28,125,000 3,500,000 shares of its common stock, no par value $0.00000002 per share (the “Shares”), and the stockholders of the Company named in Schedule B (collectively, the “Selling Stockholders”) severally propose to sell to the Underwriters an aggregate of 1,193,848 Shares. The 28,125,000 3,500,000 Shares to be sold by the Company are called referred to as “Firm Primary Shares” and the 1,193,848 Shares to be sold by the Selling Stockholders are referred to as the “Firm Secondary Shares” and collectively are referred to as the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 2,062 Shares and the Selling Stockholders have severally granted to the Underwriters an option to purchase up to an additional 702,015 Shares, with each Selling Stockholder selling up to the amount set forth opposite such Selling Stockholder’s name in Schedule B, all as provided in Section 2. The additional 4,218,750 2,062 Shares to be sold by the Company pursuant to such option are collectively called referred to as the “Optional Primary Shares” and the additional 702,015 Shares to be sold by the Selling Stockholders pursuant to such option are referred to as the “Optional Secondary Shares” and collectively are referred to as the “Optional Shares.” The Firm Primary Shares and the Optional Primary Shares are collectively referred to as the “Primary Shares” and the Firm Secondary Shares and the Optional Secondary Shares are collectively referred to as the “Secondary Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ Jefferies & Company, Incorporated Inc. (“StifelJefferies”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, S-3 (File No. 333-217645162309), including which contains a base prospectus (the “Base Prospectus”) ), to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became was declared effective by the Commission under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Basedocuments

Introductory. MEI PharmaUNITED FINANCIAL MORTGAGE CORP., Inc., a Delaware an Illinois corporation (the “"Company”"), proposes to issue and sell 800,000 shares of its authorized but unissued Common Stock, no par value (the "Firm Common Stock") to you, or if there be any so named, to the several underwriters named in Schedule A annexed hereto (the “"Underwriters”) an aggregate of 28,125,000 shares of its common stock"), par value $0.00000002 per share (the “Shares”)for whom you are acting as representative. The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted proposes to grant to you or to the Underwriters Underwriters, as the case may be, an option to purchase up to an aggregate of 120,000 additional 4,218,750 Shares shares of Common Stock (the "Optional Common Shares"), as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Common Shares and, if and to the extent such option is exercised, the Optional Common Shares are hereinafter collectively called referred to as the “Offered "Common Shares.” ▇▇▇▇▇▇" In addition, ▇▇▇the Company proposes to sell to ▇▇▇▇▇ & CompanyFinancial Services, Incorporated Inc. warrants (“Stifel”"Underwriter's Warrants") to purchase 80,000 (up-to 92,000 if the over-allotment option is exercised) pursuant to an Underwriter's Warrant Purchase Agreement between the Company and ▇▇▇▇▇ Fargo SecuritiesFinancial Services, LLC (“▇▇▇▇▇ Fargo”) Inc. You have agreed to act as representatives of advised the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular Company that you or the pluralUnderwriters, as the context requirescase may be, propose to make a public offering of their respective portions of the Common Shares on the effective date of the registration statement hereinafter referred to, or as soon thereafter as in your judgment is advisable. The Company has prepared and filed hereby confirms its agreements with respect to the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale purchase of the Offered Shares. Such registration statementCommon Shares by you or the Underwriters, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933case may be, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statementfollows.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI Pharma, Inc.Gladstone Commercial Corporation, a Delaware Maryland corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 1,400,000 shares (the “Shares”) of its common stockCommon Stock, par value $0.00000002 0.001 per share (the “SharesCommon Stock”). The 28,125,000 Company is the indirect general partner of Gladstone Commercial Limited Partnership (the “Operating Partnership”), a Delaware limited partnership that serves as the Company’s primary operating partnership subsidiary. The 1,400,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 210,000 Shares as provided in Section 2. The additional 4,218,750 210,000 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ FargoJefferies”) have has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule AA hereto, the term “RepresentativesRepresentative” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645190931, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16June 2, 2019 2014 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base Prospectus, is called the “Preliminary Prospectus,” and the Preliminary Prospectus and any other prospectus supplement to the Base Prospectus in preliminary form that describes the Offered Shares and the offering thereof and is used prior to the filing of the Prospectus (as defined below), together with the Base

Introductory. MEI Pharma, A▇▇▇▇-▇▇▇▇▇▇▇▇ Energy Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A hereto (the “Underwriters”) an aggregate of 28,125,000 3,000,000 shares (the “Firm Shares”) of its common stockCommon Stock, par value $0.00000002 0.01 per share (the “SharesCommon Stock”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares 450,000 shares (the “Optional Shares”) of Common Stock, as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares Shares, are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo”) have . RBC Capital Markets Corporation has agreed to act as representatives representative of the several Underwriters (in such capacity, the “RepresentativesRepresentative”) in connection with the offering and sale of the Offered Shares. To As more fully described in the extent there are no additional underwriters listed on Schedule ARegistration Statement (as defined below), the term Company has agreed to purchase all of the outstanding capital stock of DLS Drilling, Logistics & Services Corporation (“Representatives” as used herein shall mean youDLS”), pursuant to a stock purchase agreement dated April 27, 2006. The acquisition by the Company of all of the outstanding capital stock of DLS, as Underwritersdescribed in the Registration Statement, is referred to herein as the “Acquisition.” With respect to the representations, warranties and agreements made by the Company in this Agreement concerning its subsidiaries, such representations, warranties and agreements shall be deemed to include DLS. In connection with the Acquisition, the Company will (i) offer and sell the Securities contemplated by this Agreement; (ii) offer and sell the Notes pursuant to a purchase agreement dated August 8, 2006, among the Company, the guarantors and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared initial purchaser named therein; and filed with the Securities and Exchange Commission (iii) enter into an amendment of its $25.0 million senior secured credit facility (the “CommissionBank Credit Facility”). These transactions (but not including the offering of the Securities contemplated by this Agreement and the Registration Statement) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (are collectively referred to herein as the “Base ProspectusTransactions.”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base

Introductory. MEI PharmaThe Greenbrier Companies, Inc., a Delaware an Oregon corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A ▇▇▇▇▇▇▇ Lynch, Pierce, ▇▇▇▇▇▇ & ▇▇▇▇▇ Incorporated (the “Underwriters▇▇▇▇▇▇▇ ▇▇▇▇▇”) an aggregate of 28,125,000 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares to be sold by the Company are called the “Firm Shares.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇▇, ▇Sachs & Co. (“▇▇▇▇▇▇▇ & Company▇▇▇▇▇” and, Incorporated (“Stifel”) and together with ▇▇▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇ Fargo▇, collectively the “Initial Purchasers”), acting severally and not jointly, the respective amounts set forth in such Schedule A of $215,000,000 aggregate principal amount of the Company’s 3.50% Convertible Senior Notes due 2018 (the “Firm Notes”). The Company also proposes to issue and sell to the Initial Purchasers not more than an additional $15,000,000 principal amount of its 3.50% Convertible Senior Notes due 2018 (the “Additional Notes”) have agreed if an to act the extent the Initial Purchasers determine to exercise their option to purchase such Additional Notes. The Firm Notes and the Additional Notes are hereinafter collectively referred to as representatives the “Notes”. The Notes will be issued pursuant to an indenture, to be dated as of April 5, 2011 (the “Indenture”), between the Company and U.S. Bank National Association, as trustee (the “Trustee”) . The Notes will be convertible into shares common stock, without par value, of the several Underwriters Company (in such capacity, the “RepresentativesCommon Stock”) in connection accordance with the offering terms of the Notes and the Indenture. The Notes will be issued only in book-entry form in the name of Cede & Co., as nominee of The Depository Trust Company (the “Depositary”) pursuant to a letter of representations, to be dated on or before the Closing Date (as defined in Section 2 hereof) (the “DTC Agreement”), among the Company, the Trustee and the Depositary. The Notes and the shares of Common Stock issuable upon conversion thereof will be offered without being registered under the Securities Act of 1933, as amended (the “Securities Act”), to qualified institutional buyers in compliance with the exemptions from registration provided by Rule 144A under the Securities Act (“Rule 144A”). The net proceeds from the issuance and sale of the Offered Shares. To Notes, together with cash on hand, will be used by the extent there are no additional underwriters listed on Schedule A, Company to fund the term consummation of the Company’s offer to purchase for cash and related consent solicitation (the “Representatives” as used herein shall mean you, as UnderwritersTender Offer”) any and all of its outstanding 8.375% Senior Notes dues 2015 (the “2015 Notes”), and the term redemption (the “Underwriters” shall mean either Redemption”) of any 2015 Notes not tendered in the singular or Tender Offer. The issuance and sale of the pluralNotes, the Tender Offer, the Redemption and the payment of transaction expenses, are referred to herein collectively, as the context requires“Transactions.” This Agreement, the DTC Agreement, the Notes and the Indenture are referred to herein as the “Transaction Documents.” The Company understands that the Initial Purchasers propose to make an offering of the Notes on the terms and in the manner set forth herein and in the Pricing Disclosure Package (as defined below) and agrees that the Initial Purchasers may resell, subject to the conditions set forth herein, all or a portion of the Notes to purchasers (the “Subsequent Purchasers”) on the terms set forth in the Pricing Disclosure Package (the first time when sales of the Notes are made is referred to as the “Time of Sale”). The Company has prepared Notes are to be offered and filed sold to or through the Initial Purchasers without being registered with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called in reliance upon exemptions therefrom. Pursuant to the “Registration Statement.” Any registration statement filed by terms of the Company pursuant Notes and the Indenture, investors who acquire Notes shall be deemed to Rule 462(b) have agreed that Notes may only be resold or otherwise transferred, after the date hereof, if such Notes are registered for sale under the Securities Act in connection with or if an exemption from the offer and sale registration requirements of the Offered Shares Securities Act is called available (including the “exemptions afforded by Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement144A). The preliminary prospectus supplement Company has prepared and delivered to each Initial Purchaser copies of a Preliminary Offering Memorandum, dated December 16March 30, 2019 describing the Offered Shares and the offering thereof 2011 (the “Preliminary Prospectus Offering Memorandum”), and has prepared and delivered to each Initial Purchaser copies of a Pricing Supplement, dated March 30, 2011 (the “Pricing Supplement”), together setting forth information relating to the Company and describing the terms of the Notes, each for use by such Initial Purchaser in connection with its solicitation of offers to purchase the Notes. The Preliminary Offering Memorandum and the Pricing Supplement are herein referred to as the “Pricing Disclosure Package.” Promptly after this Agreement is executed and delivered, the Company will prepare and deliver to each Initial Purchaser a final offering memorandum dated the date hereof (the “Final Offering Memorandum”). All references herein to the terms “Pricing Disclosure Package” and “Final Offering Memorandum” shall be deemed to mean and include all information filed under the Securities Exchange Act of 1934 (as amended, the “Exchange Act,” which term, as used herein, includes the rules and regulations of the Commission promulgated thereunder) prior to the Time of Sale and incorporated by reference in the Pricing Disclosure Package (including the Preliminary Offering Memorandum) or the Final Offering Memorandum (as the case may be), and all references herein to the terms “amend,” “amendment” or “supplement” with respect to the Final Offering Memorandum shall be deemed to mean and include all information filed under the Exchange Act after the Time of Sale and incorporated by reference in the Final Offering Memorandum. The Company hereby confirms its agreements with the BaseInitial Purchasers as follows:

Introductory. MEI PharmaWinStar Communications, Inc., a Delaware corporation (the “Company”"Issuer" or "WinStar"), proposes has agreed, subject to the terms and conditions stated herein, to issue and sell (the "International Offering") to the several international underwriters named in Schedule A hereto (the “"International Underwriters”") an aggregate of 28,125,000 840,000 shares (the "International Securities") of its common stockthe Issuer's Common Stock, $0.01 par value $0.00000002 per share (the “Shares”"Common Stock"). The 28,125,000 Shares to be sold by It is understood that the Company Issuer and WinStar Multichannel Corp. ("WMC") are called concurrently entering into a U.S. Underwriting Agreement, dated the “Firm Shares.” In additiondate hereof (the "U.S. Underwriting Agreement"), with certain U.S. underwriters listed in Schedule A thereto (the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 Shares as provided in Section 2. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and"U.S. Underwriters"), if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇for whom ▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, LLC (“▇▇▇▇▇▇ Fargo”Inc. ("Salomon") have agreed to act and Credit Suisse First Boston Corporation are acting as representatives of (the several Underwriters (in such capacity, "U.S. Representatives") relating to the “Representatives”) in connection with the concurrent offering and sale of 3,360,000 shares (the Offered Shares"Firm Securities") of Common Stock in the United States and Canada (the "U.S. Offering"). To The Issuer also proposes to grant to the extent there are no U.S. Underwriters an option, exercisable by Salomon, for an aggregate of not more than 630,000 additional underwriters listed on Schedule A, shares (the term “Representatives” as used herein shall mean you, as Underwriters, "Optional Securities"). The Firm Securities and the term “Underwriters” shall mean either Optional Securities are herein collectively called the singular or "U.S. Offered Securities". The U.S. Offered Securities and the plural, International Securities are collectively referred to as the context requires"Offered Securities". The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the United States Securities Act of 19331933 is herein referred to as the "Securities Act". To provide for the coordination of their activities, as amended, the U.S. Underwriters and the rules International Underwriters have entered into an Agreement Between U.S. Underwriters and regulations promulgated thereunder (collectivelyInternational Underwriters which permits them, among other things, to sell the “Offered Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time each other for purposes of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection resale. The Issuer hereby agrees with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Baseseveral International Underwriters as follows:

Introductory. MEI Pharma, Inc.Navigator Holdings Ltd., a Delaware ▇▇▇▇▇▇▇▇ Islands corporation (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) an aggregate of 28,125,000 [•] shares of its common stock, par value $0.00000002 0.01 per share (the “Shares”); and the stockholders of the Company named in Schedule B (collectively, the “Selling Stockholders”) severally propose to sell to the Underwriters an aggregate of [•] Shares. The 28,125,000 [•] Shares to be sold by the Company and the [•] Shares to be sold by the Selling Stockholders (the “Selling Stockholders’ Firm Shares”) are collectively called the “Firm Shares.” In addition, the Company has Selling Stockholders have granted to the Underwriters an option to purchase up to an additional 4,218,750 [•] Shares as provided in Section 2. The additional 4,218,750 [•] Shares to be sold by the Company Selling Stockholders pursuant to such option are collectively called the “Optional Shares,” and together with the Selling Stockholders’ Firm Shares, are collectively called the “Selling Stockholders’ Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares.” ▇▇▇▇▇▇, ▇▇▇ LLC (“Jefferies”) and ▇▇▇▇▇▇ ▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo Securities, Co. LLC (“▇▇▇▇▇▇ Fargo▇▇▇▇▇▇▇”) have agreed to act as representatives of the several Underwriters (in such capacity, collectively, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3F-1, File No. 333-217645191782, including which contains a base form of prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the BaseRule

Introductory. MEI PharmaUlta Salon, Inc.Cosmetics & Fragrance, a Delaware corporation Inc. (the “Company”), proposes a Delaware corporation, has an authorized capital stock consisting of 70,000,000 shares, $0.01 par value, of Preferred Stock, of which no shares will be outstanding as of the First Closing Date hereinafter defined, and 400,000,000 shares, $0.01 par value, of Common Stock (“Common Stock”), of which 58,597,261 shares were outstanding as of May 10, 2010, and no other shares of Common Stock will have been issued as of the First Closing Date hereinafter defined, except for shares of Common Stock issued upon the exercise of stock options outstanding as of May 10, 2010. Certain stockholders of the Company (as named in Schedule B, the “Selling Stockholders”) propose to issue sell in the aggregate 8,976,112 shares of the Company’s issued and sell outstanding Common Stock to the several underwriters named in Schedule A as it may be amended by the Pricing Agreement hereinafter defined (the “Underwriters”) an aggregate ), who are acting severally and not jointly. Collectively, such total of 28,125,000 8,976,112 shares of its common stock, par value $0.00000002 per share (the “Shares”). The 28,125,000 Shares Common Stock proposed to be sold by the Company are called Selling Stockholders is hereinafter referred to as the “Firm Shares.” In addition, certain of the Company has granted Selling Stockholders propose to grant to the Underwriters an option options to purchase up to an aggregate of 1,346,417 additional 4,218,750 Shares shares of Common Stock (“Option Shares”) as provided in Section 25 hereof. The additional 4,218,750 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is options are exercised, the Optional Shares Option Shares, are hereinafter collectively called referred to as the “Offered Shares.” ▇▇▇▇▇▇The Common Stock, ▇▇▇▇▇▇▇▇ including the Shares, will have attached thereto rights (the “Rights”) to purchase shares of Series A Junior Participating Preferred Stock, par value $.01 per share (the “Preferred Stock”), of the Company. The Rights are to be issued pursuant to a Stockholder Rights Agreement (the “Rights Agreement”), dated as of October 25, 2007, between the Company and American Stock Transfer & Trust Company, Incorporated (“Stifel”) as Rights Agent. 1 Plus options to acquire up to an aggregate of 1,346,417 additional shares to cover overallotments. You have advised the Company and ▇▇▇▇▇ Fargo Securitiesthe Selling Stockholders that the Underwriters propose to make a public offering of their respective portions of the Shares as soon as you deem advisable after the Pricing Agreement hereinafter defined has been executed and delivered. Prior to the purchase and public offering of the Shares by the several Underwriters, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives the Company, the Selling Stockholders and the Representatives, acting on behalf of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered Shares. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as Underwriters, and shall enter into an agreement substantially in the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with the Securities and Exchange Commission form of Exhibit A hereto (the “CommissionPricing Agreement”) a shelf registration statement on Form S-3). The Pricing Agreement may take the form of an exchange of any standard form of written telecommunication among the Company, File Nothe Selling Stockholders and the Representatives and shall specify such applicable information as is indicated in Exhibit A hereto. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public The offering and sale of the Offered Shares. Such registration statementShares will be governed by this Agreement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration Statement.” Any registration statement filed supplemented by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from Pricing Agreement. From and after the date of the execution and time delivery of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” Pricing Agreement, this Agreement shall include be deemed to incorporate the Rule 462(b) Registration StatementPricing Agreement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares Company and the offering thereof (the “Preliminary Prospectus Supplement”), together Selling Stockholders hereby confirm their agreement with the BaseUnderwriters as follows:

Introductory. MEI Pharma, Xenon Pharmaceuticals Inc., a Delaware corporation continued under the federal laws of Canada (the “Company”), proposes to issue and sell to the several underwriters named in Schedule A (the “Underwriters”) (i) an aggregate of 28,125,000 8,461,542 common shares in the capital of its common stock, par value $0.00000002 per share the Company (the “Shares”) and (ii) pre-funded warrants of the Company to purchase an aggregate of 769,230 Shares (the “Pre-Funded Warrants”). The 28,125,000 8,461,542 Shares to be sold by the Company are called the “Firm Shares” and together with the Pre-Funded Warrants are referred to herein as the “Firm Securities.” In addition, the Company has granted to the Underwriters an option to purchase up to an additional 4,218,750 1,384,615 Shares as provided in Section 2. The additional 4,218,750 1,384,615 Shares to be sold by the Company pursuant to such option are collectively called the “Optional Shares.” The Firm Shares and, if and to the extent such option is exercised, the Optional Shares are collectively called the “Offered Shares” and together with the Pre-Funded Warrants are referred to herein as the “Offered Securities.” ▇.▇. ▇▇▇▇▇▇ Securities LLC (“▇.▇. ▇▇▇▇▇▇”), ▇▇▇▇▇▇▇▇▇ LLC (“Jefferies”), BofA Securities, Inc. (“BofA Securities”), ▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇ & Company, Incorporated (“Stifel”) and ▇▇▇▇▇ Fargo SecuritiesRBC Capital Markets, LLC (“▇▇▇▇▇ Fargo”) have agreed to act as representatives of the several Underwriters (in such capacity, the “Representatives”) in connection with the offering and sale of the Offered SharesSecurities. To the extent there are no additional underwriters listed on Schedule A, the term “Representatives” as used herein shall mean you, as UnderwritersUnderwriter, and the term “Underwriters” shall mean either the singular or the plural, as the context requires. The Company has prepared and filed with As used herein, “Warrant Shares” means the Securities and Exchange Commission (the “Commission”) a shelf registration statement on Form S-3, File No. 333-217645, including a base prospectus (the “Base Prospectus”) to be used in connection with the public offering and sale Shares issuable upon exercise of the Offered Shares. Such registration statement, as amended, including the financial statements, exhibits and schedules thereto, in the form in which it became effective under the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder (collectively, the “Securities Act”), including all documents incorporated or deemed to be incorporated by reference therein and any information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act, is called the “Registration StatementPre-Funded Warrants.” Any registration statement filed by the Company pursuant to Rule 462(b) under the Securities Act in connection with the offer and sale of the Offered Shares is called the “Rule 462(b) Registration Statement,” and from and after the date and time of filing of any such Rule 462(b) Registration Statement the term “Registration Statement” shall include the Rule 462(b) Registration Statement. The preliminary prospectus supplement dated December 16, 2019 describing the Offered Shares and the offering thereof (the “Preliminary Prospectus Supplement”), together with the Base