Elan Announces Closing of TYSABRI® Collaboration Transaction with Biogen Idec

Elan Announces Closing of TYSABRI® Collaboration Transaction with Biogen Idec

Chris Burns, 800-252-3526David Marshall, + 353-1-709-4444orEmer Reynolds, + 353-1-709-4022orFTI ConsultingJonathan Birt, +44-751-559-7858orSard Verbinnen & CoJamie Tully, +1-212-687-8080

Elan Corporation, plc (NYSE:ELN) is pleased to announce the closing today of the TYSABRI(natalizumab) Collaboration Transaction with Biogen Idec. The agreement was announced on February 6, 2013.

Under the terms of the agreement, Elan has received $3.25 billion in cash and will receive double digit tiered royalty payments, on all indications, for the life of the complete TYSABRI asset. For the first twelve months Elan will receive 12% royalties on in-market sales of TYSABRI, and thereafter, Elan will receive 18% royalties on in-market sales up to $2 billion and 25% royalties on in-market sales exceeding $2 billion. In 2012, in-market sales of TYSABRI were $1.6 billion.

TYSABRI is approved in more than 65 countries. TYSABRI is approved in the United States as a monotherapy for relapsing forms of MS, generally for patients who have had an inadequate response to, or are unable to tolerate, an alternative MS therapy due to the risk of progressive multifocal leukoencephalopathy (PML). In the European Union, it is approved for highly active relapsing-remitting MS (RRMS) in adult patients who have failed to respond to beta interferon or have rapidly evolving, severe RRMS.

TYSABRI has advanced the treatment of MS patients with its established efficacy. Data from the Phase 3 AFFIRM trial, which was published in the , showed that after two years, TYSABRI treatment led to a 68 percent relative reduction (p<0.001) in the annualized relapse rate when compared with placebo and reduced the relative risk of disability progression by 42-54 percent (p<0.001).

TYSABRI increases the risk of PML, an opportunistic viral infection of the brain which usually leads to death or severe disability. Infection by the JC virus (JCV) is required for the development of PML and patients who are anti-JCV antibody positive have a higher risk of developing PML. Factors that increase the risk of PML are presence of anti-JCV antibodies, prior immunosuppressant use, and longer TYSABRI treatment duration. Patients who have all three risk factors have the highest risk of developing PML. Other serious adverse events that have occurred in TYSABRI-treated patients include hypersensitivity reactions (e.g., anaphylaxis) and infections, including opportunistic and other atypical infections. Clinically significant liver injury has also been reported in the post-marketing setting. A list of adverse events can be found in the full TYSABRI product labeling for each country where it is approved.

As a result of the termination of the collaboration, TYSABRI will be marketed and distributed solely by Biogen Idec. For full prescribing information and more information about TYSABRI, please visit .

Elan is a biotechnology company, headquartered in Ireland, 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. For additional information about Elan, please visit .

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 .