Biogen Idec Prices $1.0 Billion Senior Unsecured Notes Offering

Friday, February 29, 2008 8:30 am EST

Dateline:

CAMBRIDGE, Mass.

Public Company Information:

NASDAQ:
BIIB

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Biogen Idec Inc. (NASDAQ: BIIB) announced today that it has priced a public offering of $1.0 billion principal amount of senior unsecured notes. The offering of senior unsecured notes includes $450 million in aggregate principal amount of 6.0% notes due 2013 and $550 million in aggregate principal amount of 6.875% notes due 2018. The sale of the notes is expected to close on March 4, 2008, subject to customary closing conditions.

Biogen Idec plans to use the net proceeds from this offering, together with cash on hand, to repay indebtedness under its $1.5 billion bridge facility, the proceeds of which were used to repurchase shares of Biogen Idecs common stock in a $3.0 billion Dutch Auction tender offer settled on July 2, 2007.

Goldman, Sachs & Co. and Merrill Lynch & Co. are the book-running managers for the offering. The offering of these securities is being made only by means of a prospectus and related prospectus supplement. Electronic copies of the prospectus and related prospectus supplement may be requested from Goldman, Sachs & Co. by mail at Goldman, Sachs & Co., Attention:

Prospectus Department, 85 Broad Street, New York, NY 10004, by fax at (212) 902-9316 or by email at prospectus-ny@ny.email.gs.com or by Merrill Lynch, Pierce, Fenner & Smith Incorporated at 4 World Financial Center, New York, New York 10080, Attention: Prospectus Department, 866-500-5408.

About Biogen Idec

Biogen Idec creates new standards of care in therapeutic areas with high unmet medical needs. Founded in 1978, Biogen Idec is a global leader in the discovery, development, manufacturing, and commercialization of innovative therapies. Patients in more than 90 countries benefit from Biogen Idec's significant products that address diseases such as lymphoma, multiple sclerosis, and rheumatoid arthritis. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com.

Safe Harbor

This press release contains forward-looking statements. Forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from that which we expect. Important factors that could cause our actual results to differ include our continued dependence on our two principal products, AVONEX® and RITUXAN®, the uncertainty of success in commercializing other products including TYSABRI®, the occurrence of adverse safety events with our products, the consequences of the nomination of directors for election to our Board by an activist shareholder, the failure to execute our growth strategy successfully or to compete effectively in our markets, our dependence on collaborations over which we may not always have full control, possible adverse impact of government regulation and changes in the availability of reimbursement for our products, problems with our manufacturing processes and our reliance on third parties, fluctuations in our operating results, our ability to protect our intellectual property rights and the cost of doing so, the risks of doing business internationally and the other risks and uncertainties that are described in Item 1.A. Risk Factors in our reports on Form 10-K and Form 10-Q and in other periodic and current reports we file with the SEC. These forward-looking statements speak only as of the date of this press release, and we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future events, or otherwise.

Contact:

Biogen Idec Inc.
Media Contact:
Naomi Aoki, 617-914-6524
Director, Public Affairs
or
Investment Community Contact:
Keith Regnante, 617-679-2812
Director, Investor Relations