Tokyo, Japan, July 22 and Woodcliff Lake, NJ, July 21, 2008 - With respect to Eisai's patent infringement lawsuit against Teva Pharmaceuticals and Dr. Reddy's Laboratories concerning Aciphex® (generic name: rabeprazole sodium tablets, Product Name in Japan: Pariet®), Eisai Co., Ltd. and its U.S. subsidiary Eisai Inc. (collectively “Eisai”) today announce that the United States Court of Appeals for the Federal Circuit has affirmed both the United States District Court for the Southern District of New York's summary judgment ruling on the validity of Eisai's composition of matter patent and its ruling on the enforceability of the composition of matter patent.

Eisai filed the infringement actions in November 2003 contesting Teva Pharmaceuticals and Dr. Reddy's Laboratories' submission of abbreviated new drug applications (ANDAs) to the Food and Drug Administration for Aciphex®. In October 2006, Judge Gerard E. Lynch of the United States District Court for the Southern District of New York granted partial summary judgment to Eisai, upholding the validity of the Aciphex® composition of matter patent. In a subsequent ruling in May 2007, Judge Lynch also determined that Eisai's patent is enforceable.

“We are pleased with the court of appeals' decision to uphold the district court's favorable ruling to prevent the sale of Teva's and Dr. Reddy's generic products before the expiration of the rabeprazole sodium composition of matter patent,” said Mr. Hajime Shimizu, Chairman & CEO of Eisai Corporation of North America and Eisai Inc. “Eisai will continue to actively protect its intellectual property throughout the world.”

Aciphex® is classified as a proton pump inhibitor that effectively suppresses gastric acid secretion while inhibiting enzyme activity during the last phase of stomach acid secretion. Aciphex® was launched in the United States in 1999 and is currently marketed in more than 90 countries worldwide, including Japan, the United Kingdom, and Germany. Aciphex® was discovered and developed by Eisai and is copromoted in the United States with PriCara®, a Division of Ortho-McNeil-Janssen Pharmaceuticals, Inc.

About Aciphex® (rabeprazole sodium)

In adults, Aciphex® 20 mg is indicated for: treatment of daytime and nighttime heartburn and other symptoms associated with GERD; short-term, up to 4 weeks, treatment in the healing and symptomatic relief of duodenal ulcers; short-term, 4 to 8 weeks, treatment in the healing and symptomatic relief of erosive GERD; and maintenance of healing and reduction in relapse rates of heartburn symptoms or erosive GERD (controlled maintenance studies do not extend beyond 12 months).

In adolescent patients 12 years of age and above, Aciphex® 20 mg is indicated for: short-term, up to 8 weeks, treatment of daytime and nighttime heartburn and other symptoms associated with GERD.

Important Safety Information

Aciphex® has a well-established safety profile. The most common side effect possibly related to Aciphex® is headache. Symptom relief does not rule out other serious stomach conditions. Patients on warfarin (such as Coumadin®) may need to be monitored more closely by their doctor. To learn more, talk to your doctor and see the full product information at www.aciphex.com.

About Eisai Co., Ltd.

Eisai Co., Ltd. is a research-based human health care (hhc) company that discovers, develops and markets products throughout the world. Eisai's corporate human health care (hhc) mission is to give first thought to patients and their families, and to increase the benefits that health care provides. The company believes that increasing patient satisfaction through the development of innovative new medicines exemplifies its important mission. For more information about Eisai Co., Ltd., please visit www.eisai.co.jp/index-e.html.

About Eisai Inc.

Eisai Inc. is a U.S. pharmaceutical subsidiary of Eisai Co., Ltd. Established in 1995, Eisai Inc. began marketing its first product in the United States in 1997 and has rapidly grown to become an integrated pharmaceutical business with fiscal year 2007 (year ended March 31, 2008) sales of approximately $3 billion, including the results of the acquisition of MGI PHARMA, Inc. For more information about Eisai Inc., please visit www.eisai.com(New Window).

Safe Harbor Statement

This press release may contain so-called “forward-looking statements.” These statements are based on current expectations, forecasts and assumptions that are subject to risks and uncertainties which could cause actual outcomes and results to differ materially from these statements. Risks and uncertainties include general industry and market conditions, and general domestic and international economic conditions such as interest rate and currency exchange fluctuations. Risks and uncertainties particularly apply with respect to product-related forward-looking statements. Product risks and uncertainties include, but are not limited to, technological advances and patents attained by competitors; challenges inherent in new product development, including claims and concerns about product safety and efficacy; domestic and foreign healthcare reforms; trends toward managed care and healthcare cost containment; and governmental laws and regulations affecting domestic and foreign operations. Also, there are manufacturing and marketing risks and uncertainties, which include, but are not limited to, inability to build production capacity to meet demand, unavailability of raw materials, entry of competitive products (both branded and generic), and failure to gain market acceptance. The Company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise.

Aciphex® is a registered trademark of Eisai Co., Ltd.
Coumadin® is a registered trademark of Bristol-Myers Squibb Pharma Company.

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