UCB and Biogen Idec to Collaborate on Oral Multiple Sclerosis Therapy

Brussels (Belgium) and Cambridge, MA (USA) - October 2, 2006 - 10:01 pm CET / 4:01 pm EST - UCB (Euronext Brussels: UCB) and Biogen Idec (NASDAQ: BIIB)   today announced a global collaboration to jointly develop and commercialize CDP323 for the treatment of relapsing-remitting multiple sclerosis (MS) and other potential indications. CDP323 is an orally active small molecule alpha4-integrin inhibitor expected to enter Phase II clinical trials next year.

Under terms of the agreement, UCB will receive upfront and additional payments for development and commercial milestones in excess of 200 million US dollars. Furthermore Biogen Idec will contribute significantly to clinical costs for Phase II and Phase III studies.  All commercialization costs and profits will be shared equally.

"Multiple Sclerosis affects more than a million people worldwide and we are delighted to be collaborating with Biogen Idec on our exciting CDP323 program. CDP323 has arisen from UCB's in-depth understanding of integrin biology and chemistry to address this difficult protein target.  Our outstanding Phase I results encourage us to move rapidly into Phase II trials in MS patients.  We believe that if trials are successful CDP323 could make a real difference for MS patients with this severe and debilitating disease," stated Melanie Lee, Executive Vice President, Research & Development for UCB.

"We are always looking to enhance and expand our arsenal in the fight against MS," said Al Sandrock, Senior Vice President, Neurology Research and Development for Biogen Idec.  "Another effective oral therapy would augment Biogen Idec's broad portfolio of products and potential therapies in development for this debilitating disease.  We are pleased that UCB has decided to partner with us on such a promising program."

About CDP323

CDP323 is a potent and orally active small molecule prodrug antagonist of alpha4-integrins.  The safety, tolerability and pharmacokinetic profile of CDP323 have been evaluated in healthy volunteers in three separate Phase I studies.  CDP323 was well tolerated with an adverse event profile comparable to placebo.  Data from these studies have been reported at the 2006 European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS).

About 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 50 years of age. MS is caused by damage to myelin, the protective sheath surrounding nerve fibers in the central nervous system, which interferes with messages from the brain to the body. Symptoms of MS may include vision problems, loss of balance, numbness, difficulty walking and paralysis.

About UCB

UCB (www.ucb-group.com) is a leading global biopharmaceutical company dedicated to the research, development and commercialisation of innovative pharmaceutical and biotechnology products in the fields of central nervous system disorders, allergy/respiratory diseases, immune and inflammatory disorders and oncology. UCB focuses on securing a leading position in severe disease categories.  Employing over 8,300 people in over 40 countries, UCB achieved revenue of 2.3 billion euro in 2005.  UCB is listed on the Euronext Brussels Exchange and its worldwide headquarters are located in Brussels, Belgium.

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 press releases and additional information about the company, please visit www.biogenidec.com.

UCB and Biogen Idec Safe Harbor

This press release contains forward-looking statements regarding the agreement with UCB and the development of CDP323.  Drug development involves a high degree of risk.  Only a small number of research and development programs result in commercialization of a product.  Factors which could cause actual results to differ materially from Biogen Idec's current expectations include the risk that the company may not be able to demonstrate the safety and efficacy of CDP323 at each stage of the clinical trial process; technical hurdles relating to the manufacture of CDP323 may be encountered; the company may not be able to meet applicable regulatory standards or regulatory authorities may fail to approve CDP323; and the company may encounter other unexpected hurdles.  For more detailed information on the risks and uncertainties associated with Biogen Idec's drug development activities, see the section entitled "Risk Factors" in Biogen Idec's quarterly report on Form 10-Q for the fiscal quarter ended June 30, 2006 that was filed with the Securities and Exchange Commission, as well as other periodic and current reports of Biogen Idec 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.

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