Eisai Co., Ltd. (Headquarters: Tokyo, President & CEO: Haruo Naito, “Eisai”) announced today that its U.S. subsidiary Eisai Inc. has entered into a strategic manufacturing alliance with Biogen Idec Inc. (Headquarters: Massachusetts, the United States; CEO: George A. Scangos; “Biogen Idec”) to bolster the manufacturing capabilities of both companies through the joint utilization of Eisai Inc.’s Research Triangle Park-based manufacturing facility (“the Eisai North Carolina Plant”) in North Carolina, the United States.

Under the agreement, Biogen Idec will bring some of its small molecule manufacturing capabilities in-house by leasing the oral solid dose facility of the Eisai North Carolina Plant, where it will begin manufacturing products for both companies, while Eisai Inc. will provide Biogen Idec with vial-filling services for its biologic therapies and other services. This strategic capacity-sharing alliance will enable Eisai to maximize utilization of the Eisai North Carolina Plant as well as strengthen the plant as a worldwide parenteral manufacturing hub in view of preparing for future products from the company’s pipeline and its global supply chain strategy.

The terms of the agreement provide that Biogen Idec will lease from Eisai the oral solid dose facility of the Eisai North Carolina Plant for a period of ten years and that it has the option of purchasing the oral solid dose facility building of the Eisai North Carolina Plant in the future, while Biogen Idec will receive payments from Eisai for manufacturing Eisai’s small molecule therapies, and Eisai will receive manufacturing payments for providing vial-filling services for Biogen Idec’s biological products and other services. Approximately 50 Eisai employees whose main job duties are centered on the company’s oral solid dose business are expected to become Biogen Idec employees in early 2013.

Eisai aims to respond to rapid business environment changes and diversifying customer needs in this era of great globalization to provide high-quality medicines at affordable prices and deliver products that create customer joy. In doing so, Eisai will continue to make contributions to increase the benefits provided to patients and their families worldwide.

[ Please refer to the following note for further information on Biogen Idec Inc. ]

< Notes to editors >

1. About Biogen Idec Inc.

Through cutting-edge science and medicine, Biogen Idec discovers, develops and delivers to patients worldwide innovative therapies for the treatment of neurodegenerative diseases, hemophilia and autoimmune disorders. 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 US$5 billion in annual revenues. For product labeling, press releases and additional information about the company, please visit www.biogenidec.com.