Friday, Sep 25, 1998

Biotechnology Breakthrough In Breast Cancer Wins FDA Approval

-- New Therapy for a Quarter of Women with Metastatic Breast Cancer; Testing for Protein Overexpression Critical --

SOUTH SAN FRANCISCO, Calif., -- September 25, 1998 -- Genentech, Inc., (NYSE: GNE) announced today that it received approval from the U.S. Food & Drug Administration (FDA) for Herceptin(R) (Trastuzumab), a unique new approach for treating one type of metastatic breast cancer and the first monoclonal antibody for use in this disease. The new biologic drug is expected to be available through the oncology medical community in October.

Herceptin was approved for use in patients with metastatic breast cancer who have tumors that overexpress the HER2 (human epidermal growth factor receptor2) protein. It is indicated for treatment of patients both as first line therapy in combination with paclitaxel and as a single agent in second and third line therapy.

In 25 to 30 percent of women with metastatic breast cancer, there is a genetic alteration in the HER2 gene which produces an increased amount of the growth factor receptor protein on the tumor cell surface. This HER2 protein overexpression is associated with more aggressive disease. HER2 protein overexpression is determined by an immunohistochemistry test available through a patient's physician. The test is performed on a new or stored specimen of the tumor.

"Thanks to 900 women who volunteered in the pivotal clinical trials, we have proven that Herceptin improves results in women who overexpress the HER2 protein when compared to chemotherapy alone," says Susan D. Hellmann, M.D., M.P.H., Genentech's senior vice president, development and chief medical officer. "Today heralds a new era in breast cancer with a new weapon that targets an underlying genetic defect that causes cancer."

Herceptin was generally well tolerated by the 900 women treated in clinical trials. However, Herceptin caused serious cardiac toxicity in some patients, particularly those also receiving some chemotherapy. There were mild infusion associated reactions in many patients, mostly with the first infusion. In the randomized, controlled clinical trial, the incidence of the following adverse events was higher in women receiving Herceptin in combination with chemotherapy as compared to those receiving chemotherapy alone: cardiotoxicity, leukopenia, anemia, diarrhea, abdominal pain and infections.

Arthur D. Levinson, Ph.D., Genentech's president and chief executive officer, believes Herceptin's FDA approval has special significance for the company. "Our employees feel a strong sense of accomplishment with the approval of this new therapy, one that can truly make a difference in the lives of those it helps. A significant research effort was mounted to isolate the HER2 protein and to develop the humanization technology so that clinical trials were feasible. I'm proud of the Herceptin research team that cloned the HER2 gene and am equally proud of the company's efforts in the clinical development and manufacture of this drug," he says. "Seeing the work of our employees, the clinical investigators and their staffs, breast cancer advocates and, most importantly, the patients come to fruition in today's FDA approval of Herceptin is one of the most rewarding moments of my professional life, and it will encourage our ongoing work in oncology. I would like to also acknowledge how diligent the FDA has been in partnering with Genentech to expeditiously approve this new therapy in only five months since the submission of the license application."

Herceptin is the first humanized monoclonal antibody for the treatment of HER2 overexpressing metastatic breast cancer and the second U.S. approval in this new class of biotherapeutic cancer drugs. The first was Rituxan¿ (Rituximab), developed by Genentech and its partner IDEC Pharmaceuticals Corporation, approved in November 1997.

The Importance of HER2 Testing

"Knowing that a breast cancer overexpresses HER2 can definitely influence treatment decisions," says Larry Norton, M.D., head, Division of Solid Tumor Oncology, Memorial Sloan-Kettering Cancer Center, New York. "In the past, routine testing for HER2 overexpression was not important because the results would not change management. However, recent data indicate that the proper choice of therapy may depend on this knowledge, so testing has become essential."

Testing is done on tumor tissue, and should be done at the time of diagnosis. Patients with breast cancer who want their HER2 status checked should ask their physicians to have testing done at the time of biopsy or surgery or using their stored tumor tissue.

Trial Design and the Breast Cancer Advocates

Breast cancer advocates played an important role in the Phase III clinical trials for Herceptin by partnering with Genentech to implement trials that reflect the perspective of patients with metastatic disease. The advocates' understanding helped simplify patient-entry requirements, reducing the time it took to complete enrollment.

"It is clear that moving breast cancer research forward takes collaboration," said Fran Visco, president of the National Breast Cancer Coalition, when the Phase III results were announced earlier this year at the American Society of Clinical Oncologists. "The National Breast Cancer Coalition applauds Genentech and the investigators who worked with advocates on the Herceptin clinical trials. We invite representatives of industry and the scientific community to adopt this new model for working together."

Genentech also worked closely with breast cancer advocates on the design of an expanded access program to make Herceptin available to severely ill metastatic breast cancer patients until the time of FDA approval. The program was launched in 1996 and, due to the limited supply of the drug, a lottery system was initiated to distribute the available drug without bias. In 1998, the National Cancer Institute (NCI) partnered with Genentech and successfully increased the geographic availability of Herceptin through its Treatment Referral Centers. As of September 18, 1998, the NCI is offering the drug, without the lottery, to those women who meet the expanded access program criteria.

Herceptin's Development

The HER2 gene was first linked to certain breast and ovarian cancers in 1986. Six years later in 1992, the Herceptin antibody, combined with chemotherapy, was given to the first trial group of 15 women, all considered terminally ill. By 1996, 900 women were involved in Phase III clinical trials. One of those patients, Amy Applebaum, is still receiving Herceptin therapy today:

"When I discovered I had metastatic breast cancer it was a very scary time. Participating in the Herceptin clinical trials, however, gave me strength. I am happy not only to have benefited personally from Herceptin, but to know I have helped other women who also will benefit from this drug, now that it is approved," reflected Applebaum on her experience with metastatic breast cancer and Herceptin treatment.

As with all its marketed products, Genentech will provide Herceptin therapy for patients in the United States, regardless of economic or insurance status.

Approximately 1.6 million women have been diagnosed with breast cancer in the United States. 180,000 new cases are diagnosed in any given year, according to the American Cancer Society. Genentech estimates there are approximately 164,000 women with metastatic breast cancer. Of these women, 25 to 30 percent have tumors that overexpress the HER2 protein and may potentially be candidates for this therapy.

Genentech, Inc. is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. Twelve of the currently marketed biotechnology products stem from Genentech science, seven of which Genentech markets directly in the United States. The company has headquarters in South San Francisco, California and is traded on the New York Stock Exchange and the Pacific Exchange under the symbol GNE.

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