Saturday, May 31, 2003

Preliminary Positive Data From Rituxan Multi-Center Trial in First-Line and Maintenance Therapy in Patients with Chronic Lymphocytic Leukemia (CLL)

Companies Prepare for Phase III Study in Relapsed CLL

Chicago -- May 31, 2003 --

Genentech (NYSE: DNA), IDEC Pharmaceuticals Corporation (Nasdaq: IDPH) and Roche announced today the preliminary results of a multi-center, community-based trial evaluating the safety and efficacy of Rituxan® (rituximab) (Mabthera® in Europe) therapy as a first-line and maintenance treatment for patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL), a type of non-Hodgkin's lymphoma (NHL). Results suggest that Rituxan produced high response rates in previously-untreated patients with CLL and SLL. The study was one of approximately 30 abstracts on Rituxan presented at the 39th annual American Society of Clinical Oncology (ASCO) meeting.

"The CLL and SLL patient populations have had somewhat limited treatment options to date, and the preliminary results from this study imply that Rituxan could serve as a potentially effective and less-toxic alternative to existing treatments," said John Hainsworth, M.D., Director of Clinical Research at the Sarah Cannon Cancer Center in Nashville, Tenn., also the chief investigator and presenter of the study. "The encouraging responses observed in those patients having received maintenance therapy warrant additional evaluation of Rituxan in this setting."

The study enrolled 44 patients who had previously-untreated CLL or SLL. Eligible patients received four weekly doses of Rituxan (375 mg/m2) and were re-evaluated at week six. Patients with an objective response or stable disease continued Rituxan treatment at six-month intervals, receiving 375 mg/m2 weekly for four weeks, for a total of four courses. More than half, 51 percent (22/43) of the patients experienced responses at week six, and the remaining 49 percent (21/43) of patients had stable disease. All patients have completed treatment; 45 percent (20/44) received all four planned maintenance courses of Rituxan.

After a follow-up assessment at 24 months, the current response rate for patients in this study is 58 percent (26/44), with 11 percent (5/44) experiencing complete responses. Progression-free survival is 19 months. There were no cases of Grade 3 or 4 toxicity or opportunistic infections reported during maintenance therapy in this study. Two patients had reversible Grade 3 infusion-related toxicity with the first infusion.

In addition to data presented at ASCO, Genentech, IDEC and Roche will soon begin a large, global, Phase III trial in patients with relapsed CLL. The trial will begin during the summer and will compare results of treatment with chemotherapy (fludarabine and cytoxan) vs. chemotherapy plus Rituxan. Positive data from the Phase III trial would potentially enable the companies to file a supplemental Biologics License Application (sBLA) with the U.S. Food and Drug Administration (FDA) to include certain forms of CLL as an indication in the product labeling.

"We are enthusiastic about the growing body of evidence suggesting that Rituxan may be a viable treatment for CLL at different stages of the disease," said Gwen Fyfe, M.D., vice president, Clinical Hematology/Oncology at Genentech. "The results of this trial and our decision to initiate Phase III clinical trials for relapsed CLL represent two more advancements in Genentech's continuous efforts to explore Rituxan's potential as a treatment for CLL and other difficult-to-treat cancers."

About CLL and SLL
CLL is one of four major types of leukemia and the second most common form of the disease, primarily affecting middle-aged and elderly adults. More than 8,000 people are estimated to have the disease in the United States with more than 5,000 deaths attributed to it annually. A cancer of mature B-cells called lymphocytes, CLL is manifested by progressive accumulation of cells in blood, bone marrow and lymphatic tissues. SLL, a form of B-cell non-Hodgkin's lymphoma (NHL) that is similar to CLL, accounts for approximately five percent of NHL cases in adults.

Rituxan Safety Profile
The majority of patients experience infusion-related symptoms with their first Rituxan infusion. These symptoms include but are not limited to, flu-like fever, chills/rigors, nausea, urticaria, headache, bronchospasm, angioedema and hypotension. These symptoms vary in severity and generally are reversible with medical intervention. In rare instances, severe and fatal infusion-related reactions have occurred, nearly all of which have been associated with the first Rituxan infusion. These events appear as manifestations of an infusion-related complex and include hypoxia, pulmonary infiltrates, acute respiratory distress syndrome, myocardial infarction, ventricular fibrillation, cardiogenic shock and tumor lysis syndrome. Patients who develop clinically significant infusion-related cardiopulmonary events should have their Rituxan infusion discontinued and receive medical treatment.

In rare instances, severe mucocutaneous skin reactions have occurred that may be associated with Rituxan therapy. Many of these reactions have been described as paraneoplastic pemphigus and are known to be associated with various B-cell lymphomas, particularly NHL and CLL. Patients who develop a severe mucocutaneous skin reaction should have Rituxan discontinued and receive appropriate medical treatment including a skin biopsy to guide therapy.

About Rituxan
Rituxan is a therapeutic antibody that binds to a particular protein -- the CD20 antigen -- on the surface of normal and malignant B-cells. It then recruits the body's natural defenses to attack and kill the marked B-cells. Stem cells (B-cell progenitors) in bone marrow lack the CD20 antigen, allowing healthy B-cells to regenerate after treatment and return to normal levels within several months.

Rituxan is indicated as a single-agent treatment for relapsed or refractory low-grade or follicular, CD20 positive, B-cell NHL. MabThera, in combination with CHOP chemotherapy, received European approval to treat aggressive NHL in March 2002. More than 300,000 patients have been treated with Rituxan worldwide.

Genentech and IDEC co-market Rituxan in the United States, Roche markets Rituxan in the rest of the world, except Japan where Rituxan is co-marketed by Roche and Zenyaku Kogyo Co. Ltd.

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 ten biotechnology products in the United States. The company has headquarters in South San Francisco, California 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.

About Roche
Headquartered in Basel, Switzerland, Roche is one of the world's leading innovation-driven healthcare groups. Its core businesses are pharmaceuticals and diagnostics. Roche is number one in the global diagnostics market and is the leading supplier of pharmaceuticals for cancer and a leader in virology and transplantation. As a supplier of products and services for the prevention, diagnosis and treatment of disease, the group contributes on a broad range of fronts to improving people's health and quality of life. Roche employs roughly 62,000 people in 150 countries. The group has alliances and research and development agreements with numerous partners, including majority ownership and interest in Genentech and Chugai.

About IDEC
IDEC Pharmaceuticals Corporation is a leader in the discovery, development, and commercialization of targeted immunotherapies for the treatment of cancer and autoimmune diseases. IDEC discovered and developed the first commercially available radioimmunotherapy product (Zevalin™) approved in the United States, which is used to treat certain non-Hodgkin's lymphomas. IDEC also discovered, and with co-promotion partner Genentech, Inc., developed the first monoclonal antibody product (Rituxan) approved in the United States for the treatment of cancer. Rituxan is approved in over 70 countries worldwide and is also used to treat various types of non-Hodgkin's lymphomas. IDEC is a San Diego based, integrated biopharmaceutical company with multiple products in clinical stage development and strategic alliances in a variety of research platforms.

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For full prescribing information, including Boxed Warnings, please call 650-225-5873. For more information on Rituxan, visit www.rituxan.com.