Friday, Sep 23, 2005

Genentech Provides Update on Phase II Study with Avastin in Platinum-Refractory Ovarian Cancer

South San Francisco, Calif. -- September 23, 2005 --

Genentech, Inc. (NYSE: DNA) today announced that enrollment into a multi-center, single-arm Phase II study of Avastin&® (bevacizumab) in platinum-refractory ovarian cancer patients has been discontinued due to a higher rate of gastrointestinal (GI) perforations reported than in previous studies with Avastin. Enrollment was discontinued following reports of five GI perforations observed in the first 44 patients enrolled in the proposed 53-patient study. The patients currently enrolled in the trial will be informed of the new safety information and, in consultation with their physician, may continue to receive protocol treatment with Avastin or elect to discontinue treatment.

"GI perforations are a known possible adverse event with Avastin; however, we chose to discontinue enrollment in this Phase II study due to the observation of a higher rate seen in this study than in other trials of Avastin in ovarian cancer or other tumor types," said Hal Barron, M.D., Genentech's senior vice president, development, and chief medical officer. "We are continuing our plans to study Avastin in ovarian cancer based on the activity seen to date and the significant unmet medical need in this patient population, and currently do not expect these results to affect our plans to study Avastin in earlier-stage ovarian cancer or other tumor types."

The decision to discontinue enrollment was made by Genentech in consultation with the FDA. Study investigators are being notified today so they can have informed conversations with their patients.

"The limited overall number of GI perforations seen in this study prevent us from ascertaining definitive risk factors for this adverse event. Patients enrolled in this study had more advanced disease, which typically involves the bowel, and had received more prior chemotherapy than in previous clinical trials of Avastin in ovarian cancer," said Barron.

About Avastin
Avastin is a therapeutic antibody designed to inhibit Vascular Endothelial Growth Factor (VEGF), a protein that plays an important role in tumor angiogenesis and maintenance of existing tumor vessels. By binding to VEGF, Avastin is designed to interfere with the blood supply to tumors, a process that is critical to tumor growth and metastasis. The FDA approved Avastin on February 26, 2004 as a first-line treatment for metastatic colorectal cancer in combination with intravenous 5-FU-based chemotherapy. For full prescribing information, including Boxed Warnings for Avastin and information about Avastin and angiogenesis, visit http://www.gene.com or http://www.avastin.com.

Based on data showing that VEGF may play a broad role in a range of cancers, Genentech is pursuing a late-stage clinical development program with Avastin evaluating its potential use in adjuvant and metastatic colorectal, renal cell (kidney), breast, non-small cell lung and ovarian cancers. Avastin is also being evaluated in earlier stage trials as a potential therapy in a variety of solid tumor cancers and hematologic malignancies. For further information about Avastin clinical trials, please call 888-662-6728.

Avastin Safety Profile
Avastin has a well-established safety profile. In Genentech-sponsored studies, the most serious adverse events associated with Avastin were gastrointestinal perforation, wound healing complications, hemorrhage, arterial thromboembolic events, hypertensive crisis, nephrotic syndrome and congestive heart failure. The most common Grade 3-4 adverse events (occurring in greater than two percent of patients in the Avastin arm, compared to the control group) were asthenia, pain, hypertension, diarrhea and leukopenia. The most common adverse events (occurring in greater than two percent of patients in the Avastin arm, compared to the control group) of any severity were asthenia, pain, abdominal pain, headache, hypertension, diarrhea, nausea, vomiting, anorexia, stomatitis, constipation, upper respiratory infection, epistaxis, dyspnea, exfoliative dermatitis and proteinuria.

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, Calif., 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.

# # #
For full prescribing information, including Boxed Warnings for Avastin, please call 800-821-8590 or visit http://www.gene.com.

This press release contains forward-looking statements regarding our plans to study Avastin in advanced ovarian cancer in earlier lines of therapy or other tumor types. Actual results could differ materially. Among other things, our plans to study Avastin in ovarian cancer or other tumor types could be affected by unexpected safety or efficacy issues, discussions with the FDA or FDA actions. Genentech disclaims, and does not undertake, any obligation to update or revise any forward-looking statements in this press release.