TYSABRI is marketed and distributed by Biogen Idec Inc. and Elan Corporation, plc. For full prescribing information and more information about TYSABRI, please visit www.biogenidec.com.About Biogen Idec Biogen Idec uses cutting-edge science to discover, develop, manufacture and market therapies for serious diseases with a focus on neurology, immunology and hemophilia. Founded in 1978, Biogen Idec is the world's oldest independent biotechnology company. Patients worldwide benefit from its leading multiple sclerosis therapies and the company generates more than $5 billion in annual revenues. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com. About Elan Elan Corporation, plc is a neuroscience-focused biotechnology company committed to making a difference in the lives of patients and their families by dedicating itself to bringing innovations in science to fill significant unmet medical needs that continue to exist around the world. Elan shares trade on the New York and Irish Stock Exchanges. For additional information about Elan, please visit www.elan.com. Biogen Idec Safe Harbor Statement This press release contains forward-looking statements, including statements about the expected accretion to earnings per share from the transaction, TYSABRI’s growth prospects, the synergies we expect from the transaction, and the closing of the transaction. These forward-looking statements may be accompanied by such words as “anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,” “potential,” “project,” “target,” “will” and other words and terms of similar meaning. You should not place undue reliance on these statements. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements, including uncertainty inherent in regulatory review of the transaction, our dependence on our three principal products, AVONEX ® (interferon beta-1a), TYSABRI and RITUXAN ® (rituximab), the importance of TYSABRI’s sales growth, uncertainty of success in commercializing and developing other products, product competition, the occurrence of adverse safety events with our products, changes in the availability of reimbursement for our products, adverse market and economic conditions, our dependence on collaborations and other third parties over which we may not always have full control, problems with our manufacturing processes and our reliance on third parties, failure to comply with government regulation, our ability to protect our intellectual property rights and have sufficient rights to market our products together with the cost of doing so, the risks of doing business internationally, failure to manage our growth and execute our growth initiatives, charges and other costs relating to our properties, fluctuations in our effective tax rate, our ability to attract and retain qualified personnel, product liability claims, fluctuations in our operating results, the market, interest and credit risks associated with our portfolio of marketable securities, environmental risks and the other risks and uncertainties that are described in the Risk Factors section of our most recent annual or quarterly report and in other reports we have filed with the SEC. These statements are based on our current beliefs and expectations and speak only as of the date of this press release. We do not undertake any obligation to publicly update any forward-looking statements.