Eisai Inc. (Headquarters: Woodcliff Lake, New Jersey, Chairman and CEO: Hajime Shimizu, "Eisai") today announces the successful completion of its acquisition of the biopharmaceutical company, AkaRx, Inc. (Headquarters: Bridgewater, New Jersey, CEO: Robert E. Desjardins), for approximately $255 million. As a result of this acquisition, AkaRx is now a wholly-owned subsidiary of Eisai Inc. and Eisai has the exclusive worldwide rights to develop, market and manufacture AKR-501.

AKR-501 is an investigational thrombopoietin receptor agonist that, based on preclinical studies, increases platelet production by stimulating megakaryocytic proliferation and differentiation. Eisai is currently conducting Phase II clinical trials of AKR-501 in the United States as a potential treatment for idiopathic thrombocytopenic purpura (ITP) and thrombocytopenia associated with liver diseases (TLD), and has confirmed proof of concept in the clinical studies for ITP. In addition, Eisai will explore the compound's potential as a treatment for chemotherapy-induced thrombocytopenia (CIT).

Eisai Inc.

Eisai Inc. was established in 1995 and is ranked among the top-20 U.S. pharmaceutical companies (based on retail sales). The company began marketing its first product in the United States in 1997 and has rapidly grown to become a fully integrated pharmaceutical business with fiscal year 2008 (year ended March 31, 2009) sales of approximately $3.7 billion. Eisai Inc.'s areas of commercial focus include neurology, gastrointestinal disorders and oncology/critical care. Headquartered in Woodcliff Lake, New Jersey, the company serves as the U.S. pharmaceutical operation of Eisai Co., Ltd., a research-based human health care (hhc) company that discovers, develops and markets products throughout the world.

Eisai has a global product creation organization that includes U.S.-based R&D facilities in Maryland, Massachusetts, New Jersey, North Carolina and Pennsylvania as well as manufacturing facilities in Maryland and North Carolina. The company's areas of R&D focus include neuroscience; oncology; vascular, inflammatory and immunological reaction; and antibody-based programs. For more information about Eisai, please visit www.eisai.com.

*On October 1, 2009, Eisai Research Institute of Boston, Inc. (established in 1987) and Eisai Medical Research Inc. (established in 2002) were merged into Eisai Inc.

Eisai Co., Ltd.

Eisai Co., Ltd. is a research-based human health care (hhc) company that discovers, develops and markets products throughout the world. Through a global network of research facilities, manufacturing sites and marketing subsidiaries, Eisai actively participates in all aspects of the worldwide health care system. Eisai employs approximately 11,000 employees worldwide.

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SOURCE: Eisai Inc.

CONTACT: For Media: Suzanne Grogan, Eisai Inc., +1-201-746-2083; For
Investor Inquiries: Bob Laverty, Eisai Inc., +1-201-746-2265

Web Site: http://www.eisai.com/