To: tuck who wrote (477 ) 6/5/2003 7:05:18 PM From: scaram(o)uche Read Replies (2) | Respond to of 598 Item 4. Purpose of Transaction. From time to time in the past, where circumstances warranted, Amgen has acquired equity securities of public and private companies with which Amgen has had a collaborative, licensing or other strategic relationship. Representatives of Amgen have been involved in discussions with the Issuer over the past several months concerning the possibility of forming one or more collaborations around certain of the Issuer’s scientific programs. In connection with such discussions, Amgen and the Issuer entered into a Letter Agreement dated February 11, 2003 (the “Confidentiality Agreement and Standstill”). Pursuant to the Confidentiality Agreement and Standstill, the Issuer provided Amgen with information regarding the Issuer’s programs and product candidates. On May 21, 2003, Amgen and the Issuer entered into a Collaboration Agreement. The Collaboration Agreement contemplates a transaction in which (i) Amgen and the Issuer will collaborate on discovery and development of anti-cancer agents that target oncogene encoded proteins, (ii) the Issuer granted Amgen worldwide commercialization rights for certain products resulting from the collaboration 4 -------------------------------------------------------------------------------- (the “Products”), (iii) Amgen granted limited co-promotion rights to the Issuer in the United States and (iv) Amgen agreed to fund research costs and make specified payments upon achievement of certain predetermined clinical milestones and to pay a royalty on net sales of Products. Amgen will acquire the Issuer Shares in connection with the collaboration. Amgen may enter into additional discussions with the Issuer regarding additional collaborations, joint ventures and licensing transactions. The Confidentiality Agreement and Standstill permitted Amgen to acquire all of the shares of Common Stock held by Pharma Vision. Pursuant to an amendment to the Confidentiality Agreement and Standstill dated May 21, 2003, the Issuer granted Amgen a waiver of the restrictions on stock purchase contained in the Confidentiality Agreement and Standstill in connection with Amgen’s acquisition of the Issuer Shares. In connection with the acquisition of the Pharma Vision Shares and the Issuer Shares: (i) the Issuer amended its Rights Agreement dated as of December 11, 2001 between the Issuer and Wells Fargo Bank Minnesota, N.A., as Rights Agent (the “Issuer Rights Agreement”) to provide that Amgen and its affiliates will not be an Acquiring Person (as such term is defined in the Issuer Rights Agreement) so long as it does not acquire beneficial ownership of additional shares of the Issuer’s Common Stock; and (ii) the Issuer agreed to enter into a Registration Rights Agreement, a form of which is attached to the Issuer Stock Purchase Agreement and pursuant to which the Issuer will register for resale all of the Pharma Vision Shares and the Issuer Shares. From time to time representatives of Amgen and the Issuer have engaged in preliminary discussions concerning a possible business combination. In each case, such discussions were terminated at a preliminary stage without resulting in any agreements. Subject to the requirements of the Confidentiality Agreement and Standstill, such discussions could be renewed at any time in the future, the outcome of which would depend on the parties’ ability to reach agreement on pricing, structure and other terms. Amgen intends to closely monitor and evaluate the business affairs, financial position and performance of the Issuer, including, but not limited to, an analysis and assessment of the capital markets in general, developments concerning the Issuer and the Issuer’s share price, capital structure, management, and prospects. Depending on these and other factors deemed relevant by Amgen, subject to the requirements of the Confidentiality Agreement and Standstill and the provisions of the Issuer Rights Agreement, Amgen may, directly or indirectly, acquire additional shares of Common Stock as it deems appropriate, in open market purchases, privately negotiated transactions or otherwise. Alternatively, Amgen may dispose of some or all of its shares of Common Stock now owned or, subject to the Lockup Provision, hereafter acquired by it, in open market sales, privately negotiated transactions or otherwise. Except as disclosed above, Amgen acquired the Pharma Vision Shares and the Issuer Shares for investment purposes.