Press Release Details

FOR IMMEDIATE RELEASE

THOUSAND OAKS, Calif., and COLLEGEVILLE, Pa., July 8, 2003 - Amgen (NASDAQ: AMGN) and Wyeth Pharmaceuticals, a division of Wyeth (NYSE: WYE), today announced a supplemental Biologics License Application (sBLA) has been submitted to the U.S. Food and Drug Administration (FDA) for the use of ENBREL. (etanercept) to treat moderate to severe plaque psoriasis. Psoriasis is an inflammatory disease affecting nearly seven million people in the United States and is characterized by chronic inflammation of the skin.

"We are pleased to have submitted an application for the first therapy that targets Tumor Necrosis Factor (TNF), the dominant inflammatory cytokine in psoriasis," said Dr. Beth Seidenberg, Amgen's senior vice president of development. "In the clinical studies, many patients treated with ENBREL experienced significant improvement in their symptoms."

Results of the Phase 3 trials were reported in March at the American Academy of Dermatology annual meeting and in June at the International Psoriasis Symposium.

"ENBREL is well studied with nearly five years of post-marketing experience across approved indications and has an established tolerability profile which we know is important to the dermatology community," said Dr. Alice Gottlieb, professor of medicine at the University of Medicine and Dentistry of New Jersey - Robert Wood Johnson Medical School.

Adverse events were similar to those reported in previous clinical trials of ENBREL in patients with RA.

"ENBREL has been studied in nearly 1,200 psoriasis patients participating in the pivotal trials," said Dr. Victoria Kusiak, vice president of global medical affairs and North American medical director of Wyeth Pharmaceuticals. "This filing marks an important milestone for ENBREL because it is the fifth inflammatory disease submission in five years. ENBREL is currently approved to treat rheumatoid arthritis, juvenile rheumatoid arthritis, and psoriatic arthritis, and is under review for use in ankylosing spondylitis."

Psoriasis is characterized by chronic inflammation of the skin. This inflammation drives the formation of red, itchy skin plaques that are painful and disfiguring. Tumor necrosis factor (TNF) is found at high levels in psoriatic plaques, and plays a critical role in their formation and maintenance. Psoriasis affects nearly seven million people in the United States, one million of whom have moderate to severe plaque psoriasis.

Neither the outcome nor the timing of FDA action on this submission can be predicted with certainty. FDA may approve or disapprove the application, request additional data, or take other administrative actions.

ABOUT ENBREL

ENBREL is the only fully human anti-TNF receptor approved for use to reduce the signs and symptoms of active arthritis in patients with psoriatic arthritis, and to reduce the signs and symptoms and inhibit the structural damage in patients with moderately to severely active rheumatoid arthritis (RA). ENBREL is the only biologic therapy approved to treat newly diagnosed RA patients, and can be used alone. It is also approved to reduce the signs and symptoms of moderately to severely active polyarticular-course juvenile rheumatoid arthritis (JRA) in patients who have had an inadequate response to disease-modifying medicines.

Physicians have become familiar with the benefits and proven long-term tolerability profile of ENBREL. It has been used to treat more than 180,000 patients worldwide since becoming commercially available nearly five years ago.

ENBREL acts by binding TNF, one of the dominant inflammatory cytokines or regulatory proteins that play an important role in both normal immune function and the cascade of reactions that causes the inflammatory process. The binding of ENBREL to TNF renders the bound TNF biologically inactive, resulting in significant reduction in inflammatory activity.

Since the product was first introduced, the following have been reported in patients using ENBREL:

• Serious Infections

- Many occurred in people prone to infection, such as those with advanced or poorly controlled diabetes

- Some serious infections were fatal

- Rare cases of tuberculosis

• What to do/Not do

- Do not start ENBREL if you have an infection or are allergic to ENBREL or its components

- Tell your doctor if you are prone to infection

- Stop ENBREL if a serious infection occurs

- Contact your doctor if you have questions about ENBREL or develop an infection

• Serious nervous system disorders such as multiple sclerosis, seizures, or inflammation of the nerves of the eyes.

- Tell your doctor if you have ever had any of these disorders or if you develop them after starting ENBREL.

• Rare reports of serious blood disorders (some fatal)

- Contact your doctor immediately if you develop symptoms such as persistent fever, bruising, bleeding, or paleness

• The incidence of cancer has not increased with extended exposure to ENBREL and is similar to the expected rate.

• ENBREL can also cause injection site reactions.

• In a medical study of patients with JRA, infections, headaches, abdominal pain, vomiting, and nausea occurred more frequently than in adults.

- The kinds of infections reported were generally mild and similar to those usually seen in children

- Other serious adverse reactions were reported rarely, including serious infections (2%) and depression/personality disorder (1%)

Amgen and Wyeth Pharmaceuticals, a division of Wyeth, market ENBREL in North America. Other Wyeth affiliates market ENBREL outside of North America. Immunex Corporation, a wholly owned subsidiary of Amgen, manufactures ENBREL. Additional information about ENBREL, including full Prescribing Information, can be found on the Web site sponsored by the companies at www.enbrel.com or by calling toll free 888-4ENBREL (888-436-2735).

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

Wyeth Pharmaceuticals, a division of Wyeth, has leading products in the areas of women's health care, cardiovascular disease, central nervous system, inflammation, hemophilia, oncology and vaccines. Wyeth is one of the world's largest research-driven pharmaceutical and health care products companies. It is a leader in the discovery, development, manufacturing, and marketing of pharmaceuticals, vaccines, biotechnology products and non-prescription medicines that improve the quality of life for people worldwide. The Company's major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Healthcare and Fort Dodge Animal Health.

This news release contains forward-looking statements that involve significant risks and uncertainties, including those discussed below and others that can be found in Amgen's Form 10-K for the year ended December 31, 2002, and in Amgen's periodic reports on Form 10-Q and Form 8-K. Amgen is providing this information as of the date of this news release and does not undertake any obligation to update any forward-looking statements contained in this document as a result of new information, future events or otherwise.

No forward-looking statement can be guaranteed and actual results may differ materially from those we project. Amgen's results may be affected by its ability to successfully market both new and existing products domestically and internationally, sales growth of recently launched products, difficulties or delays in manufacturing its products, and regulatory developments (domestic or foreign) involving current and future products and manufacturing facilities. In addition, sales of Amgen's products are affected by reimbursement policies imposed by third party payors, including governments, private insurance plans and managed care providers, and may be affected by domestic and international trends toward managed care and healthcare cost containment as well as possible U.S. legislation affecting pharmaceutical pricing and reimbursement. Government regulations and reimbursement policies may affect the development, usage and pricing of Amgen's products. Furthermore, Amgen's research, testing, pricing, marketing and other operations are subject to extensive regulation by domestic and foreign government regulatory authorities. Amgen or others could identify side effects or manufacturing problems with its products after they are on the market. In addition, Amgen competes with other companies with respect to some of its marketed products as well as for the discovery and development of new products. Discovery or identification of new product candidates cannot be guaranteed and 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. In addition, while Amgen routinely obtain patents for its products and technology, the protection offered by its patents and patent applications may be challenged, invalidated or circumvented by its competitors. Further, some raw materials, medical devices and component parts for Amgen's products are supplied by sole third party suppliers.

The statements in this press release that are not historical facts are forward-looking statements based on current expectations of future events that involve risks and uncertainties including, without limitation, risks associated with the inherent uncertainty of pharmaceutical research, product development, manufacturing, and commercialization, and economic conditions, including interest and currency exchange rate fluctuations, the impact of competitive or generic products, product liability and other types of lawsuits, the impact of legislative and regulatory compliance and obtaining approvals, and patents, and other risks and uncertainties, including those detailed from time to time in Wyeth's periodic reports, including quarterly reports on Form 10-Q and the Annual Report on Form 10-K, filed with the Securities and Exchange Commission. Actual results may vary materially from the forward-looking statements. Wyeth assumes no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

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For further information, please contact:

Media: 805-447-4587 Wyeth Pharmaceuticals

Investors: 805-447-1060 Douglas Petkus (media)

484/865-5140

Justin Victoria (investors)

973/660-5340

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