21 APPENDIX I IILEX ONCOLOGY, INC. REGISTRATION STATEMENT QUESTIONNAIRE The undersigned (the "Selling Stockholder") a purchaser of Common Stock (the "Registrable Shares") of ILEX Oncology, Inc. (the "Company") purchased pursuant to the Purchase Agreement, dated as of March __, 2000 by and between the Company and the Selling Stockholder (the "Purchase Agreement"), hereby elects to include in the Registration Statement for the registration and resale of the Registrable Shares, the Registrable Shares listed below in Item (3) (unless otherwise specified under Item 3). The undersigned agrees to be bound with respect to such Registrable Shares by the terms and conditions of this Registration Statement Questionnaire and the Purchase Agreement. Upon any sale of Registrable Shares pursuant to the Registration Statement under the Securities Act of 1933, as amended (the "Securities Act"), the Selling Stockholder will be required to deliver to the Company the Notice of Transfer set forth in Appendix II attached hereto (completed and signed) and hereby undertakes to do so. The Selling Stockholder hereby provides the following information to the Company and represents and warrants that such information is accurate and complete: