Amgen Stockholders Approve Issuance of Shares in Connection with Immunex Acquisition

THOUSAND OAKS, Calif. - May 16, 2002 - Amgen (Nasdaq: AMGN), announced that its stockholders approved the issuance of shares of Amgen common stock in connection with the company's proposed acquisition of Immunex Corporation (Nasdaq: IMNX) at Amgen's 2002 Annual Meeting of Stockholders held today. Upon the completion of the acquisition, Immunex shareholders will receive 0.44 of a share of Amgen common stock and $4.50 in cash for each share of Immunex common stock that they own.

Immunex will also be holding its 2002 Annual Meeting of Shareholders today at which its shareholders will be considering the approval of the merger agreement with Amgen. Wyeth (formerly American Home Products Corp.), which beneficially owns approximately 41 percent of Immunex's outstanding shares, previously agreed to vote all of its shares in favor of the transaction.

"We are very pleased by Amgen's stockholders' overwhelming support for the transaction," said Kevin Sharer, Amgen's Chairman and Chief Executive Officer. "With this acquisition, Amgen, the world's largest biotechnology company, will acquire the Seattle-based biotechnology company, Immunex. Upon the close of this transaction, we look forward to adding Enbrel(R), a proven blockbuster in the treatment of inflammation, to Amgen's portfolio of blockbuster medicines." Sharer said.

In addition to Immunex shareholder approval, the close of the transaction remains subject to certain customary regulatory approvals, as well as other customary closing conditions.

This news release contains forward-looking statements that involve significant risks and uncertainties, including those discussed below and more fully described in the Securities and Exchange Commission reports filed by Amgen, including our most recent Form 10-Q. Whether the consents and approvals necessary to complete the transaction can be obtained is uncertain. Furthermore, Amgen can give no assurance when and if the acquisition will be completed. Amgen conducts research in the biotechnology/pharmaceutical field where movement from concept to product is uncertain; consequently, there can be no guarantee that any particular product candidate will be successful and become a commercial product.

Furthermore, our research, testing, pricing, marketing and other operations are subject to extensive regulation by domestic and foreign government regulatory authorities. In addition, sales of our products are affected by reimbursement policies imposed by third party payors, including governments, private insurance plans and managed care providers. These government regulations and reimbursement policies may affect the development, usage and pricing of our products.

In addition, while we routinely obtain patents for our products and technology, the protection offered by our patents and patent applications may be challenged, invalidated or circumvented by our competitors.

Because forward-looking statements involve risks and uncertainties, actual results may differ materially from current results expected by Amgen. Amgen is providing this information as of May 16, 2002 and expressly disclaims any duty to update information contained in this press release.

Amgen is a global biotechnology company that discovers, develops and manufactures important human therapeutics based on advances in cellular and molecular biology.

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Contact: Amgen, Thousand Oaks
Jeff Richardson, 805-447-3227
Cary Rosansky, 805/447-4634 (investors)