FOR IMMEDIATE RELEASE

ABC²:
Media Contact: John Reher (650) 685-2200

Genentech:
Media Contact: Colleen Sweeney (650) 225-7739
Investor Contact: Kathee Littrell (650) 225-1034

GENENTECH AND ABC² AGREE TO COLLABORATE
ON BRAIN CANCER CLINICAL TRIAL

BURLINGAME and SOUTH SAN FRANCISCO, Calif. - May 8, 2003 - Accelerate Brain Cancer Cure (ABC²), a non-profit association dedicated to accelerating therapies leading to a cure for brain cancer, and Genentech, Inc. (NYSE: DNA), today announced that they have agreed on terms under which the ABC² Clinical Network will be used for a clinical trial with Tarceva™ (erlotinib HCl) in glioblastoma multiforme (GBM), an advanced form of brain cancer. Tarceva is designed to inhibit the tyrosine kinase activity of the HER1/EGFR signaling pathway inside the cell, which may block tumor cell growth. Tarceva is currently being studied as an oral tablet by an alliance of Genentech, OSI Pharmaceuticals (Nasdaq: OSIP), and Roche (SWX: Zurich).

"Based on encouraging results of a Phase I study with Tarceva in glioma, we recently made the decision to initiate a Phase II study," said Gwen Fyfe, M.D., Genentech's vice president of Clinical Hematology/ Oncology. "We welcome the opportunity to work with the ABC² Clinical Network, which includes many preeminent neuro-oncology centers in the United States."

The ABC² Clinical Network provides guidance and counsel to ABC² and various sponsors of therapeutics in the design and execution of early stage, molecularly targeted clinical trials for adult GBM. Charter members of the network include four leading neuro-oncology centers: University of California, San Francisco; University of California, Los Angeles; Duke University; and M.D. Anderson Cancer Center. The network's focus is to understand and exploit specific abnormalities in individual patients through science-driven trials and to locate appropriate patients for clinical trials. In addition, a key component of the ABC² Clinical Network is the acquisition and testing of tumor tissue to understand the effects of treatment in specific patients, and to raise awareness of the need for available tissue samples among patients.

As a 501(c)(3) tax-exempt, non-profit foundation, ABC² funds outstanding and novel translational science that is aimed at the discovery of a cure for brain cancer. Under the collaboration agreement with Genentech, ABC² is funding a portion of the trial and will receive commensurate royalties if Tarceva is approved for GBM, which it will use to fund future translational research programs.

ABC² was founded in May 2001 by the late Dan Case, former Chief Executive Officer and Chairman of Hambrecht & Quist; his brother Steve Case, Chairman of AOL/Time Warner; their families; and a group of leading scientists and entrepreneurs.

John Reher, Executive Director of ABC², commented, "Although Dan Case succumbed to brain cancer last June, he was very excited about the potential of Tarceva and would be pleased that, in collaboration with Genentech, his legacy lives on in support of Tarceva's potential. We look forward to this program and other opportunities to bring meaningful therapies to brain cancer patients."

About Brain Cancer
Primary brain cancer kills up to 10,000 Americans a year, and more than 100,000 patients are diagnosed with a brain tumor that has metastasized from another part of the body. Brain tumors are typically treated by surgery, radiation therapy and chemotherapy, either individually or in combination. Present therapies are inadequate, as evidenced by the low 5-year survival rate for brain cancer patients, with median survival at approximately 12 months.

About Tarceva
Tarceva is a small molecule designed to target the human epidermal growth factor receptor 1 (HER1) pathway, which is critical to cell growth in many cancers. HER1, also known as EGFR (epidermal growth factor receptor), is a key component of the HER signaling pathway, which often is involved in the formation and growth of numerous cancers. High expression of HER1/EGFR may be associated with GBM, providing the rationale for clinical testing of Tarceva as a potential therapy.

Tarceva is in Phase III clinical development for first-line and second-/third-line metastatic non-small cell lung cancer and metastatic pancreatic cancer. Early clinical trials are also underway examining the use of Tarceva with various chemotherapeutic regimens for advanced cancer patients.

About ABC²
ABC² aims to raise awareness about brain cancer and help mobilize critical scientific research through research grants and partnerships. ABC²'s mission is to accelerate a cure for brain cancer by increasing the number of potential therapies discovered and then rapidly moving them into the clinic to help patients. In order to accelerate progress in what has been an under-served field of research, ABC² provides researchers from all backgrounds with the support they need to make critical breakthroughs in brain cancer research. Further information can be found at: www.abc2.org.

About Genentech
Genentech is a leading biotechnology company that discovers, develops, manufactures, and commercializes biotherapeutics for significant unmet medical needs. Fifteen of the currently approved biotechnology products originated from, or are based on, Genentech science. Genentech manufactures and commercializes 10 biotechnology products directly in the United States. The company has headquarters in South San Francisco, Calif., and is traded on the New York Stock Exchange under the symbol DNA. For press releases and additional information about the company, please visit http://www.gene.com.

# # #