Cambridge, MA – April 3, 2006– Biogen Idec (NASDAQ: BIIB) announced today that data published in the March 14, 2006 issue of Neurology demonstrated that AVONEX delayed the risk of developing clinically definite multiple sclerosis (MS) for up to five years in patients who began treatment immediately after their initial MS attack.

The study, known as CHAMPIONS (Controlled High Risk AVONEX Multiple Sclerosis Prevention Study In Ongoing Neurological Surveillance), was designed to determine whether the effect of early treatment with AVONEX in delaying relapses and reducing the accumulation of MS brain lesions could be sustained for up to five years.

“These CHAMPIONS data provide unique insight into the effect of AVONEX for up to 5 years when initiated early in the course of MS,” said lead study investigator R. Philip Kinkel, M.D., Director of the Multiple Sclerosis Center at Beth Israel Deaconess Medical Center in Boston, MA and Associate Professor of Neurology at Harvard Medical School. “CHAMPIONS provides additional evidence that patients who start on AVONEX earlier have a sustained advantage over those patients who start therapy later.”

The study followed patients who began treatment immediately after their initial MS attack and compared this to initiation of treatment more than two years after onset of symptoms. The patients studied were considered at risk of suffering additional MS attacks because of the presence of brain MRI scan abnormalities.

The 203 MS patients who enrolled in the CHAMPIONS study were followed for a total of five years after their initial attack. Patients who began treatment with AVONEX immediately after their first attack had a 43% decrease in the risk of developing a second attack compared to those who began treatment on placebo, after adjusting for the potential confounding effects of age, CHAMPS qualifying event, CHAMPS baseline brain MRI T2 lesion volume, and baseline number of gadolinium-enhancing lesions.

About the Study

CHAMPIONS is an open-label extension of CHAMPS, (Controlled High Risk Subjects AVONEX Multiple Sclerosis Prevention Study), a randomized, double-blind, placebo-controlled Phase III clinical trial involving 383 patients who had just experienced their first MS attack and who had brain MRI scan abnormalities characteristic of MS. In CHAMPS, AVONEX-treated patients experienced a 44% decrease in the rate of developing a second attack when compared to placebo over a three-year period. Based on the CHAMPS results, the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) approved AVONEX to be used in patients who have experienced a first clinical episode if they have brain MRI scan abnormalities consistent with MS.

Multiple Sclerosis

MS is a chronic disease of the central nervous system that affects approximately 400,000 people in North America and more than one million people worldwide. It is a disease that affects more women than men, with onset typically occurring between 20 and 40 years of age. Symptoms of MS may include vision problems, loss of balance, numbness, difficulty walking and paralysis.


AVONEX is the most prescribed treatment for relapsing forms of multiple sclerosis worldwide, with more than 130,000 patients on therapy. It was launched in the U.S. in 1996 and later in Europe for the treatment of relapsing forms of MS to slow the progression of disability and reduce relapses. AVONEX is marketed internationally in more than 90 countries. AVONEX was the first treatment approved for MS patients who have their first clinical MS attack and have a brain MRI scan that suggests MS; this use was approved in Europe in 2002 and in the U.S. in 2003.

The most common side effects associated with AVONEX treatment are flu-like symptoms including myalgia, fever, fatigue, headache, chills, nausea, vomiting, pain and asthenia.

AVONEX should be used in caution with patients with depression or other mood disorders and in patients with seizure disorders. AVONEX should not be used by pregnant women. Patients with cardiac disease should be closely monitored. Patients should also be monitored for signs of hepatic injury. Routine periodic blood chemistry and hematology tests are recommended during treatment with AVONEX. Rare cases of anaphylaxis have been reported. Please see complete prescribing information available at .

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 .

Safe Harbor/Forward Looking Statements

This press release contains forward-looking statements regarding AVONEX that are subject to a number of risks and uncertainties. These statements are based on the companies’ current beliefs and expectation. No forward-looking statement can be guaranteed. 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 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.


For more information contact:


Amy Brockelman
Senior Manager, Public Affairs
Biogen Idec
(617) 914-6524


Oscar Velastegui
Senior Manager, Investor Relations
Biogen Idec
(617) 679-2812