Tuesday, Dec 8, 1998

Rituxan Follow-Up Data Shows 28 Percent of Responders Still in Remission

More than 12,000 U.S.Patients Treated in First Year

Miami Beach, Fla. -- December 8, 1998 --

Genentech, Inc. (NYSE:GNE) and IDEC Pharmaceuticals Corporation (NASDAQ:IDPH) today announced the results obtained from the long-term follow-up single agent pivotal trial of the companies' Rituxan® (Rituximab). These data were presented at the annual meeting of the American Society of Hematology (ASH). Rituxan is the only approved monoclonal antibody therapy for non-Hodgkin's lymphoma (NHL) and the first new agent in 11 years for NHL. Rituxan currently is being studied in other clinical trials for a variety of indications.

Analyses of these follow-up data indicate that 48 percent (80 out of 166) of patients with relapsed or refractory low-grade or follicular, CD20-positive, B-cell non-Hodgkin's lymphoma responded to treatment with Rituxan. Six percent were complete responses and 42 percent were partial responses. Median duration of response is 11.6 months. Twenty-two of the 80 responders (28 percent) are experiencing ongoing remissions lasting from one-and-a-half to three years. These follow-up data on the median response duration have not yet been submitted to the Food and Drug Administration (FDA) for review.

Responses, as measured by CT scans, were confirmed in a blinded audit by independent lymphoma experts (LEXCOR) using the rigorous complete response criteria of < 1.0 x 1.0 cm for normal lymph node size. "We concluded that without clearly defined or standardized response criteria for NHL, reports of anticancer agent results cannot be reliably compared in literature reports, preventing the ability to accurately assess NHL biologic treatment responses," says Bruce D. Cheson, M.D., Head, Medicine Section, Cancer Therapy Evaluation Program, National Cancer Institute, one of the study's authors.

"This study also confirmed that patients treated with Rituxan after their first chemotherapy relapse had a higher response rate (57 percent) than those treated after second or third relapses from chemotherapy (38 percent)," says Peter McLaughlin, M.D., associate professor of medicine, University of Texas, M.D. Anderson Cancer Center. In refractory patients, the overall response rate was 29 percent or 6 out of 21. "These data from the pivotal trial indicate that Rituxan provides durable remissions in patients who typically experience multiple relapses with shorter disease-free intervals after each treatment," says Antonio Grillo-Lopez, IDEC Pharmaceutical's chief medical officer.

The results of a Phase II Rituxan re-treatment study also were presented at ASH. This Phase II study in patients with low-grade or follicular, CD20-positive, B-cell NHL was conducted to determine the safety and efficacy of Rituxan in patients who had relapsed or were refractory to prior chemotherapy, but who had responded previously to Rituxan. It appears from the initial analyses of the study that patients who responded to one regimen of Rituxan may be re-treated with additional courses of Rituxan without impairment of bone marrow function (myelosuppression), development of an immune response (antibodies), or CD20 antibody therapy -- a response called human anti-chimeric antibody (HACA).

Of 60 patients treated, 56 were considered evaluable for efficacy. The overall response rate was 41 percent, with 7 out of 56 (12.5 percent) being complete responders and 16 out of 56 (28.6 percent) being partial responders. Median time to progression and duration of response have not been reached after more than 10 months of follow-up. While the overall safety profile seen with treatment was similar to what was reported for the initial treatment with Rituxan (primarily infusion-related events that usually occurred within a few hours of the first infusion) other events that occurred less frequently included: leukopenia, nausea, transient bronchospasm, and mild hypotension. These results will be submitted to the FDA in the second quarter of 1999.

Rituxan was approved for marketing by the FDA in November 1997. In less than a year on the market, Rituxan has been used to treat more than 12,000 patients worldwide. The most commonly reported adverse events associated with use of Rituxan alone are infusion-related and consist of flu-like symptoms (e.g., fever, chills, rigors) that occur in the majority of patients during the first infusion. Other events that occur with less frequency include nausea, rashes, fatigue and headache. More serious events include hypotension, wheezing, sensation of tongue and throat swelling, and recurrence of cardiac events in patients with a history of angina or arrhythmia. Severe or life-threatening events of bronchospasm and hypotension can occur in 1 percent of patients and are generally reversible with medical intervention.

On December 5, 1998, Genentech and IDEC notified doctors of the occurrence of severe infusion-related adverse events that have resulted in eight fatalities worldwide since product launch. In seven of the eight fatalities, severe symptoms occurred during the first infusion. The cause of death was not reported or remains unknown for two of the eight cases.

There are more than 250,000 patients in the United States with B-cell non-Hodgkin's lymphomas, which are malignancies of the body's antibody-producing immune system cells. Of these patients, approximately one-half are low-grade or follicular lymphoma patients and the other 50 percent are intermediate-grade to high-grade lymphoma patients. Currently, standard treatment for low-grade NHL consists of chemotherapy and/or radiotherapy.

IDEC Pharmaceuticals discovered Rituxan. Rituxan was developed in collaboration with Genentech, F. Hoffmann-La Roche, Ltd of Switzerland and Zenyaku Kogyo Co., Ltd. of Japan. IDEC and Genentech co-promote Rituxan in the United States and have shared responsibility for product manufacture. Roche is responsible for marketing Rituxan in the rest of world, excluding Japan.

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 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 of GNE.

F. Hoffmann-La Roche, Ltd, with headquarters in Basel, Switzerland, is a member of the Roche Group, a world leader in research-based health care with major businesses in pharmaceuticals, diagnostics, vitamins and fine chemicals, and fragrances and flavors. Roche has a long tradition of innovative breakthroughs in drug development and is a pioneer in the medical applications of genetic engineering.

IDEC Pharmaceuticals focuses on developing targeted immunotherapies for the treatment of cancer and autoimmune diseases which are primarily designed to act through immune mechanisms. IDEC Pharmaceuticals and Rituxan are registered U.S. trademarks. IDEC is headquartered in San Diego, California.

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