William D. Young To Retire From Biogen Idec’s Board of Directors

Biogen Idec (NASDAQ: BIIB) announced today that Chairman of the Board William D. (Bill) Young will retire from the Company’s Board of Directors, effective at the Company’s 2014 annual meeting of stockholders. Mr. Young has been a member of Biogen Idec’s Board of Directors since 1997 and has served as Chairman of the Board since 2010.

"Bill’s leadership and dedication to Biogen Idec cannot be overstated. The integrity and determination that he brought to this organization serve as a benchmark for future leaders to follow,” said George A. Scangos, Ph.D., chief executive officer of Biogen Idec. "On behalf of the Board of Directors and Biogen Idec, I would like to thank Bill for his long-standing service and wish him the best for the future.”

Reflecting on his years on the Biogen Idec Board, Mr. Young said: "I want to thank the employees of Biogen Idec, whose dedication to science and devotion to the mission have made a tremendous impact on the lives of the patients we serve. I expect a very bright future for Biogen Idec as this mission continues.”

Stelios Papadopoulos, Ph.D., a member of Biogen Idec’s Board of Directors since 2008, has been appointed to assume the role of Chairman of the Board following the end of Mr. Young’s term. Dr. Papadopoulos is the former Vice Chairman of Cowen & Co. LLC and is the current Chairman of the Board at Exelixis, Inc., a drug discovery company that he cofounded in 1994, and at Regulus Therapeutics, Inc. Dr. Papadopoulos is also currently a member of the Board of Directors of BG Medicine, Inc.

"Bill took over as chairman at a difficult time for the company, went on to unify the Board, spearheaded the recruitment of a new management team and presided over a time of unprecedented growth for the company. His record will be hard to match,” said Dr. Papadopoulos

About Biogen Idec

Through cutting-edge science and medicine, Biogen Idec discovers, develops and delivers to patients worldwide innovative therapies for the treatment of neurodegenerative diseases, hemophilia and autoimmune disorders. Founded in 1978, Biogen Idec is the world’s oldest independent biotechnology company. Patients worldwide benefit from its leading multiple sclerosis therapies. For product labeling, press releases and additional information about the Company, please visit www.biogenidec.com.