Tuesday, May 21, 2002

Investigational Data Demonstrates Potential Use of Rituxan in Various CD20-Positive Cancers

Orlando, Fla. -- May 21, 2002 --

Genentech, Inc. (NYSE: DNA) and IDEC Pharmaceuticals Corporation (Nasdaq: IDPH) today announced initial positive results from studies examining the role of Rituxan® (Rituximab) in the treatment of various CD20 positive cancers, including front-line indolent and relapsed aggressive non-Hodgkin's lymphoma (NHL) and lymphocyte predominant Hodgkin's disease (LPHD). These results were presented at the annual meeting of the American Society of Clinical Oncology (ASCO).

"We continue to be encouraged by the results seen from the ongoing study of Rituxan in numerous forms of CD20-positive malignancies," said Gwen Fyfe, M.D., Genentech's senior director of Oncology, Medical Affairs. "The data generated from these studies highlight the productive clinical trial program that has been implemented with our partners, and driven by key investigators, that has helped establish Rituxan as one of the most significant new cancer therapies in the United States."

Rituxan Plus Short Term Chemotherapy in Low-Grade NHL (Abstract #1070)

In this study, led by Dr. John D. Hainsworth of the Sarah Cannon Cancer Center, 86 patients with previously-untreated low-grade NHL received four weeks of Rituxan (375 mg/m2 weekly) followed at week five by three additional courses of Rituxan plus standard CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) or CVP (cyclophosphamide, vincristine, prednisone) chemotherapy, which was given every three weeks for three cycles. The type of chemotherapy was chosen by the treating physician and based upon patient characteristics.

To date, 98 percent (80/82) of patients have responded to treatment. Furthermore, 57 percent (47/82) experienced a complete response, defined as disappearance of all signs of cancer, with 40 percent (33/82) achieving a partial response, defined as a decrease in tumor size of more than 50 percent and 3 percent (2/82) experiencing stable disease. After median follow-up of 15 months, 87 percent of patients (75/82) are progression-free.

Furthermore, of the 35 patients found to have a positive test for Bcl-2 rearrangement (a molecular marker of B-cell lymphoma) prior to treatment, 22 had this test examined again after completion of therapy. Sixteen of these 22 patients (73 percent) had converted to negative Bcl-2 status, thus signifying molecular remission.

One patient experienced a Grade 3/4 infusion-related toxicity during treatment with Rituxan only. When patients received Rituxan in combination with chemotherapy Grade 3/4 hematologic toxicities included leukopenia (33 percent), thrombocytopenia (2 percent) and neutropenia/fever (11 percent). One patient died of pneumonia, which was not neutropenic, but possibly treatment-related.

Use of Eight-Weekly Infusions in Relapsed Aggressive NHL (Abstract #1142)

Dr. Tadahiko Igarashi of the National Cancer Hospital East of Japan reported results from a multicenter Phase II study designed to evaluate the safety and efficacy of eight weekly infusions of Rituxan (375 mg/m2) in 57 evaluable patients with relapsed aggressive B-cell NHL.

To date, 37 percent (21/57) of patients responded to eight weekly infusions of Rituxan with 26 percent (15/57) achieving a complete response and 11 percent (6/57) achieving a partial response. The median time to progression in the 21 responders has not been reached at 245 days and the median duration of response has not been reached at 52 days.

Adverse events for 67 enrolled patients in this study were mostly Grade 1/2 and transient. The most common Grade 1/2 events included fever (61 percent), chills (30 percent), burning sensation (24 percent), asthenia (21 percent) and headache (18 percent). Hematologic Grade 3/4 events included leukopenia (4 patients/Grade 3 and 1 patient/Grade 4) and neutropenia (7 patients/Grade 3 and 4 patients/Grade 4).

"The studies by Drs. Hainsworth and Igarashi provide further support for the safety and activity of Rituxan in combination with chemotherapy in front-line indolent NHL, and as a single agent in relapsed aggressive NHL, respectively," said Dr. Fyfe. "These studies are significant in that they support previously-reported data with Rituxan in these two types of NHL."

Rituxan in lymphocyte predominant Hodgkin's disease (LPHD): results of a Phase II trial (Abstract #1052)

Results from a Phase II study, led by Dr. Sandra Horning of Stanford University Medical Center, of Rituxan in lymphocyte predominant Hodgkin's disease (LPHD) were discussed in an oral presentation. LPHD is a type of Hodgkin's disease that tends to relapse frequently despite radiation or chemotherapy treatment and is characterized by CD20-positive malignant cells, the target for Rituxan.

Nineteen evaluable patients with untreated or relapsed CD20-positive LPHD and measurable disease received four weekly doses of Rituxan (375mg/m2). All 19 patients (100 percent) responded to Rituxan therapy, with a clinical complete response in eight patients (42 percent), two complete responses with no evidence of residual disease after CAT scan (11 percent) and partial responses in nine patients (47 percent).

After a median of 12 months follow-up, nine of the 19 patients relapsed, and the median freedom from progression (FFP) was 10 months. Four patients were retreated after relapsing, with one achieving a partial response and the other two experiencing stable disease. The fourth retreated patient developed CD20-positive diffuse large cell lymphoma and became PET negative after retreatment with Rituxan.

According to the investigators, treatment-related adverse events were minimal and included no Grade 3 or 4 toxicities.

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. More than 250,000 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 with Zenyaku Kogyo Co. Ltd.

About NHL and LPHD

There are more than 300,000 people in the United States with B-cell NHL. Approximately 50 percent have low-grade or follicular lymphoma, while the other half are patients with aggressive NHL. Overall, NHL is the second fastest growing cancer in terms of incidence and deaths in the United States and is diagnosed in more than 56,000 men and women each year.

A rare and chronic cancer, LPHD is a CD20-positive B-cell disease that is distinct from classic Hodgkin's disease, which is CD20 negative. Patients with lymphocyte-predominant disease have earlier-stage disease, longer survival, and fewer treatment failures than those with classic Hodgkin's disease. LPHD accounts for about five percent of all Hodgkin's disease cases. It is three times more common in men than in women, and it primarily affects young adults.

Rituxan Post-Marketing 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 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 stem from or are based on Genentech science. Genentech manufactures and commercializes ten biotechnology products directly 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.

About IDEC

IDEC Pharmaceuticals focuses on the commercialization and development of targeted therapies for the treatment of cancer and autoimmune diseases. IDEC's antibody products act chiefly through immune system mechanisms, exerting their effect by binding to specific, readily targeted immune cells in the patient's blood or lymphatic systems.

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For more information, please visit www.rituxan.com.