AVONEX® (Interferon beta-1a) GAINS MEDICARE COVERAGE

Senior Citizens and Individuals with Disabilities Now Have Increased Access to Leading Multiple Sclerosis Therapy

Biogen, Inc. (NASDAQ/BGEN) announced that Medicare will provide coverage for multiple sclerosis patients treated with AVONEX as part of physician services. The action by the Center for Medicare and Medicaid Services (CMS) implements a law passed by Congress to restore Medicare coverage for certain injectable prescription medicines.

James Mullen, President and CEO of Biogen said, “Members of Congress and this Administration can take pride in helping expand Medicare drug coverage for MS patients.”

About Biogen

Biogen, Inc., winner of the U.S. National Medal of Technology, is a biopharmaceutical company principally engaged in discovering and developing drugs for human healthcare through genetic engineering. Headquartered in Cambridge, MA, the Company’s revenues are generated from U.S. and worldwide sales of AVONEX® (Interferon beta-1a) for treatment of relapsing forms of multiple sclerosis, and from the worldwide sales by licensees of a number of products. Biogen’s research and development activities are focused on novel products to treat inflammatory and autoimmune diseases, neurological diseases, cancer, fibrosis and congestive heart failure. The Company maintains active clinical research programs in protein therapeutics, small molecules, genomics and gene therapy. For copies of press releases and additional information about the Company, please consult Biogen’s Homepage on the World Wide Web at http://www.biogen.com.

Notes to Editors:

In December 2000, Congress clarified and expanded Medicare coverage of drugs and biologics by adding a provision (Section 112) to the Benefits Improvement and Protection Act of 2000 (BIPA). This provision reversed an August 1997 program memorandum by CMS, which resulted in the termination of Medicare coverage for AVONEX and had an adverse impact on coverage for other injectable therapies. Medicare covered AVONEX when it was first approved in the U.S. in 1996 until the 1997 program memorandum.

AVONEX is given once a week as an intramuscular injection. Intramuscular drugs have traditionally been covered by Medicare.

The action by CMS implements the BIPA provision on injectable drugs.

Individuals seeking additional information may go to the CMS website at http://cms.hhs.gov/media/