UNDERWRITING AGREEMENTUnderwriting Agreement • June 18th, 2009 • Immunogen Inc • Pharmaceutical preparations • New York
ImmunoGen, Inc., a Massachusetts corporation (the “Company”), proposes, subject to the terms and conditions contained herein, to sell to you, Oppenheimer & Co. Inc., and the other underwriters named on Schedule I to this Agreement (the “Underwriters”), for whom you are acting as Representative (the “Representative”), an aggregate of 5,000,000 shares (the “Firm Shares”) of the Company’s common stock, $.01 par value per share (the “Common Stock”). In addition, the Company proposes to grant to the Underwriters an option to purchase up to an additional 750,000 shares (the “Company Option Shares”) of Common Stock from the Company for the purpose of covering over-allotments in connection with the sale of the Firm Shares. The Firm Shares and the Option Shares are collectively called the “Shares.”
