Positive Results Of Phase III Study Of Rituxan In Rheumatoid Arthritis To Be Presented At American College Of Rheumatology Meeting

Study Shows a Greater Proportion of Rituxan-Treated Patients Achieved American College of Rheumatology 20, 50 and 70 Responses Compared to Placebo

SAN DIEGO - November 16, 2005 - Biogen Idec (Nasdaq: BIIB) and Roche (SWX Zurich) today announced positive results of a Phase III clinical study of Rituxan® (Rituximab) in rheumatoid arthritis (RA), showing that a significantly greater proportion of patients who received a single course of two infusions of Rituxan with a stable dose of methotrexate (MTX) achieved American College of Rheumatology (ACR) 20, 50 and 70 response rates compared to patients who received placebo and MTX. The study included patients with active RA who have had an inadequate response or were intolerant to prior treatment with one or more anti-TNF therapies. These data were submitted to the U.S. Food and Drug Administration (FDA) as part of a supplemental Biologics License Application for Rituxan that is currently under Priority Review. These findings will be presented today during a plenary session at the ACR Annual Scientific Meeting in San Diego.

In the 24-week multi-center, double-blind, and placebo-controlled study, known as REFLEX, 520 patients were randomized to receive either Rituxan or placebo, in combination with a stable dose of MTX. At 24 weeks, those receiving Rituxan displayed clinically and statistically significant improvements in RA symptoms compared to placebo. In patients receiving Rituxan:

* 51 percent achieved ACR 20, the primary endpoint of the study, versus 18 percent of placebo patients;
* 27 percent achieved ACR 50, versus 5 percent of placebo patients;
* 12 percent achieved ACR 70, versus 1 percent of placebo patients.

“Few options exist for patients who inadequately respond to anti-TNF therapy,” said abstract lead author and presenter Stanley B. Cohen, M.D., Clinical Professor of Internal Medicine, University of Texas, Southwestern Medical School. “We are encouraged that these pivotal data from REFLEX may highlight the viability of Rituxan as a potentially new and important treatment approach for this difficult-to-treat patient population.”

These data did not reveal any unexpected safety signals. The most frequently reported adverse events in the study were primarily infusion-related. Serious adverse events occurred in 7 percent of patients receiving Rituxan and MTX compared to 10 percent in patients receiving placebo and MTX. The incidence of serious infections was low in both groups (2 percent in Rituxan-treated patients and 1 percent in placebo patients). The companies are committed to monitoring long-term safety of Rituxan in all clinical trials.

About ACR Response

ACR 20, ACR 50 and ACR 70 responses indicate a 20, 50 and 70 percent improvement in the number of swollen and tender joints, respectively, as well as a 20, 50 and 70 percent improvement compared with baseline in three of five disease-activity measures: patient assessment, physician assessment, pain scale, Health Assessment Questionnaire and the value for one acute phase reactant (erythrocyte sedimentation rate or C-reactive protein).

About RA

RA is a debilitating autoimmune disease that affects more than two million Americans1 and hinders the daily activities of sufferers. RA occurs when the immune system inappropriately attacks joint tissue, causing painful chronic inflammation and irreversible destruction of cartilage, tendons and bones, often resulting in disability. While RA has traditionally been considered a T-cell-mediated disease, emerging research suggests that other immune cells called B cells may play multiple roles in the pathophysiology of RA, including autoantibody production, T-cell activation and cytokine production. Common RA symptoms include inflammation of the joints, swelling, fatigue, stiffness and pain. Additionally, since RA is a systemic disease, it can have effects in other tissues such as the lungs, eyes and bone marrow.

About Rituxan

Rituxan is a therapeutic antibody that targets and selectively depletes CD20-positive B cells without targeting stem cells or existing plasma cells. Rituxan is currently under Priority Review by the U.S. Food and Drug Administration for patients with active RA who inadequately respond to anti-TNF therapy. Rituxan is also being studied in other autoimmune diseases, including lupus, multiple sclerosis and ANCA-associated vasculitis.

Rituxan, discovered by Biogen Idec, received FDA approval in November 1997 for the treatment of relapsed or refractory, low-grade or follicular, CD20-positive, B-cell non-Hodgkin’s lymphoma (NHL). It was approved in the European Union under the trade name MabThera® in June 1998. Recently, the FDA accepted a supplemental biologics license application for Priority Review of Rituxan for front-line treatment of intermediate grade or aggressive, CD20-positive, B-cell NHL. Genentech and Biogen Idec co-market Rituxan in the United States, and Roche markets MabThera in the rest of the world, except Japan, where Rituxan is co-marketed by Chugai and Zenyaku Kogyo Co. Ltd. Rituxan has been used to treat more than 730,000 patients worldwide. For a copy of the Rituxan full prescribing information, including Boxed Warning, please call 1-800-821-8590 or visit www.gene.com.

Rituxan Safety Profile in non-Hodgkin’s Lymphoma

In NHL patients, 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 chronic lymphocytic leukemia. 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 Biogen Idec

Biogen Idec creates new standards of care in oncology, neurology and immunology. As a global leader in the development, manufacturing, and commercialization of novel therapies, Biogen Idec transforms scientific discoveries into advances in human healthcare. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com.

About Roche

Headquartered in Basel, Switzerland, Roche is one of the world’s leading research-focused healthcare groups in the fields of pharmaceuticals and diagnostics. As a supplier of innovative products and services for the early detection, 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 is a world leader in diagnostics, the leading supplier of medicines for cancer and transplantation and a market leader in virology. In 2004 sales by the Pharmaceuticals Division totaled 21.7 billion Swiss francs, while the Diagnostics Division posted sales of 7.8 billion Swiss francs. Roche employs roughly 65,000 people in 150 countries and has R&D agreements and strategic alliances with numerous partners, including majority ownership interests in Genentech and Chugai.

Biogen Idec Safe Harbor

This press release contains forward-looking statements regarding RITUXAN as a treatment for RA. These statements are based on the companies’ current beliefs and expectation. Drug development involves a high degree of risk. Factors which could cause actual results to differ materially from the companies’ current expectations include: the risk that unexpected concerns may arise from additional data or analysis, that regulatory authorities may require additional information, further studies, or may fail to approve the drug, or that the company may encounter other unexpected hurdles. For more detailed information on the risks and uncertainties associated with Biogen Idec’s drug development and other activities, see the periodic reports of Biogen Idec Inc. filed with the Securities and Exchange Commission. Biogen Idec assumes no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

1American College of Rheumatology, 2005, www.rheumatology.org/public/factsheets/ra.asp?aud=pat

Contact Information

Jose Juves

Biogen Idec

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