Thursday, Sep 23, 2004

Genentech and Wyeth Announce Manufacturing Agreement

South San Francisco, CA and Collegeville, PA -- September 23, 2004 --

Genentech, Inc. (NYSE: DNA) and Wyeth Pharmaceuticals, a division of Wyeth (NYSE: WYE), today announced that the companies have entered into a manufacturing agreement for Herceptin® (Trastuzumab). Under this agreement, Wyeth Pharmaceuticals will manufacture Herceptin bulk drug substance for Genentech at Wyeth's production facility in Andover, Massachusetts. Financial terms of the agreement have not been disclosed.

"Wyeth has a strong track record as a manufacturer of biopharmaceuticals, and we are very pleased to enter into this agreement for the production of Herceptin, which will assist us in our mission of delivering life-saving therapies to patients," said David A. Ebersman, senior vice president, Product Operations, Genentech. "The additional capacity provided by this agreement will help us manufacture product in response to increases in demand for our therapeutic antibody products."

"This agreement provides Wyeth with an important opportunity to continue to build our biopharmaceutical business by working with Genentech, which is one of the industry's leaders in biotechnology and oncology innovation," said Cavan Redmond, executive vice president and General Manager, Wyeth BioPharma. "We are looking forward to using our biotechnology expertise and experience to manufacture this key oncology product in our Andover facility."

About Herceptin
Herceptin is a targeted therapeutic antibody treatment for women with HER2-positive metastatic breast cancer, an especially aggressive form of the disease that affects approximately one-fourth of women with breast cancer. Special testing is required to identify women who are HER2-positive and candidates for treatment with Herceptin.

Herceptin received U.S. Food and Drug Administration (FDA) approval in September 1998 for use in women with metastatic breast cancer who have tumors that overexpress the HER2 protein. It is indicated for weekly treatment of patients both as first-line therapy in combination with paclitaxel and as a single agent in second- and third-line therapy. Herceptin is marketed in the United States by Genentech and internationally by Roche.

In clinical trials, Herceptin has shown an important survival benefit when used in combination with doxorubicin or epirubicin plus cyclophosphamide, or paclitaxel. In December 2001, Genentech received FDA approval to include data that showed a 24 percent increase in median overall survival for women with HER2-positive metastatic breast cancer treated initially with Herceptin and chemotherapy compared to chemotherapy alone (median 25.1 months compared to 20.3 months).

Herceptin Safety Profile
Administration of Herceptin can result in the development of ventricular dysfunction and cardiac failure.

Severe hypersensitivity reactions (including anaphylaxis), infusion reactions, and pulmonary events have been infrequently reported. Rarely, these were fatal. In clinical trials, the incidence and severity of cardiac dysfunction was highest in patients receiving Herceptin with anthracycline and cyclophosphamide (AC). Most patients responded to medical therapy, including discontinuation of Herceptin. However, some patients were successfully managed while continuing Herceptin therapy.

In clinical trials, approximately 40 percent of patients experienced symptoms such as chills and fever during the first infusion. These and other symptoms, including nausea, vomiting, and pain, occurred infrequently with subsequent infusions. There was an increased incidence of anemia leukopenia, diarrhea, and infection when Herceptin was used in combination with chemotherapy.

For Herceptin full prescribing information, including boxed warning, please call (650) 467-6450 or visit http://www.gene.com.

About Genentech
Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes biotherapeutics for significant unmet medical needs. A considerable number of the currently approved biotechnology products originated from or are based on Genentech science. Genentech manufactures and commercializes multiple biotechnology products directly in the United States and licenses several additional products to other companies. The company has headquarters in South San Francisco, California and is traded on the New York Stock Exchange under the symbol DNA. For additional information about the company, please visit http://www.gene.com.

Regarding Genentech
The statement made in this press release related to Genentech's ability to manufacture product in response to increases in demand for our therapeutic antibody products is forward-looking and actual results could differ materially. Among other things, Genentech's ability to manufacture product could be affected by a number of factors, including problems with Genentech's or a contractor's manufacturing process, insufficient capacity, a prolonged interruption in the operations of Genentech's or a contractor's manufacturing facilities, the inability of a supplier to provide raw materials, equipment failures or malfunctions, damage to a facility, changes in FDA regulatory requirements or standards, actions by the FDA, a contractor going out of business or failing to produce product or a delay in construction of new facilities.

About Wyeth Pharmaceuticals
Wyeth Pharmaceuticals, a division of Wyeth, has leading products in the areas of women's health care, cardiovascular disease, central nervous system, inflammation, transplantation, hemophilia, oncology, vaccines and nutritional products. 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 nonprescription medicines that improve the quality of life for people worldwide. The Company's major divisions include Wyeth Pharmaceuticals, Wyeth Consumer Health Care, and Fort Dodge Animal Health.

Regarding Wyeth
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 the timing and success of pharmaceutical research, product development, manufacturing, commercialization, economic conditions including interest and currency exchange rate fluctuations, changes in generally accepted accounting principles, the impact of competitive or generic products, trade buying patterns, wars or terrorist acts, product liability and other types of lawsuits, the impact of legislation and regulatory compliance and obtaining reimbursement, favorable drug pricing, access and other approvals, environmental liabilities, and patent, and other risks and uncertainties, including those detailed from time to time in Wyeth's periodic reports, including current reports on Form 8-K, 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 and Genentech assume no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

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