Eisai Announces Agreement with Pfizer on Strategic Alliance for Alzheimers Disease Treatment Aricept®

Eisai Co., Ltd. (Headquarters: Tokyo, President and CEO: Haruo Naito, “Eisai”) announced that it has reached a comprehensive agreement with Pfizer Inc. (Headquarters: New York, CEO and Chairman of the Board: Jeffrey Kindler, “Pfizer”) regarding the strategic alliance for the Alzheimers Disease treatment, Aricept® (donepezil hydrochloride). Eisai and Pfizer have been in discussions to resolve their dispute concerning the strategic alliance and development agreement which was signed in October 1994.

Main items which both parties agreed upon are as follows;

1 A partial alteration of the Agreement for Aricept®

Under this redefined alliance, Eisai and Pfizer will continue to co-promote Aricept® in the U.S., Japan and key markets in Europe. The expiry of the Agreement for the co-promotion of Aricept® in Japan will cease as of 31st of December, 2012.

2 New partnership in connection with a new product developed by Pfizer

Eisai will co-promote pregabalin in Japan, a treatment for neuropathic pain developed by Pfizer. Pfizer launched pregabalin in the U.S. and Europe with the brand name, Lyrica® and has filed a New Drug Application (NDA) in Japan.

Eisai expects this new agreement with Pfizer to have a positive impact on its revenue and earnings after fiscal year 2010.

Eisai will continue its hhc mission to address unmet medical needs and make contributions to improving the quality of life of patients, their families and caregivers.