BIOGEN PRAISES COURT RULING THAT AVONEX® DOES NOT INFRINGE BERLEX

Biogen, Inc. (NASDAQ/BGEN) today announced that Judge Mark L. Wolf of the Federal District Court for the District of Massachusetts granted summary judgment that Biogen’s AVONEX® (Interferon beta-1a) product, does not infringe either of the “McCormick” patents held by Berlex Laboratories, Inc. (U.S. Patent Nos. 5,376,567 and 5,795,779). The judge concluded, “It is now appropriate to enter final judgement for Biogen in an appropriate form.”

Biogen markets AVONEX®, the world’s leading drug for treatment of multiple sclerosis. Berlex markets a competing interferon beta product. The McCormick patents relate to methods of producing interferon beta products.

James C. Mullen, Biogen’s President and Chief Executive Officer, said, “We are very pleased with today’s ruling. We have always been very confident we had a strong legal position in this dispute. Today’s decision vindicates our position. We are anxious to put this matter behind us.”

In addition to historical information, this press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Reference is made in particular to forward-looking statements regarding predictions as to the final resolution of pending litigation. These statements are based on the Company’s current beliefs and expectations as to such future outcomes. Factors which could cause actual results to differ materially from the Company’s current expectations include the risk that future determinations or decisions adverse to the Company will be made during the course of the lawsuit or on appeal, if any.

Biogen, Inc., winner of the 1998 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 European 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, including alpha interferon and hepatitis B vaccines and diagnostic products ( Prescribing Information ). Biogen’s research and development activities are focused on novel products for multiple sclerosis, inflammatory, respiratory, kidney and cardiovascular diseases and in developmental biology 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.