Paul Hastings Wins Patent Trial for Eisai Pharmaceuticals 

May 14, 2007

Paul Hastings Wins Patent Trial for Eisai Pharmaceuticals

New York, NY (May 14, 2007) -- Paul, Hastings, Janofsky & Walker LLP (Paul Hastings), a leading international law firm, won an important patent trial on behalf of Eisai Co. Ltd. regarding the pharmaceutical company's billion dollar a year stomach acid suppression medication, Aciphex.

Following a two week trial in March, the U.S. District Court in the Southern District of New York ruled Friday that Eisai's patent on Aciphex's active ingredient rabeprazole was enforceable - effectively defeating efforts by Teva Pharmaceuticals and Dr. Reddy's Laboratories to sell generic versions of the drug in the U.S. prior to the expiration of Eisai's patent in 2013.

The generic drugmakers had charged that Eisai's patent should be held unenforceable because Eisai had allegedly failed to disclose a copending patent application covering a drug molecule that was almost identical to the active ingredient of Aciphex. This failure was alleged to have been done with the intent to deceive the Patent Office.

Despite an earlier enforceability ruling by the Court, which was widely interpreted as leaning against Eisai's position and that spawned multiple class action antitrust lawsuits against Eisai, Paul Hastings attorneys convinced District Judge Gerard E. Lynch that although the compounds of the two patent applications were similar, they produced distinctly different effects. Judge Lynch also found Eisai's patent attorneys to be credible in their good faith explanations for their actions.

In October 2006, Paul Hastings had won a partial summary judgment for Eisai, upholding the validity of Aciphex's composition of matter patent. Eisai's patent is valid until May 8, 2013.  With Friday's trial ruling, Paul Hastings ended more than three years of litigation and secured a total victory in this "bet your company" case for Eisai, which had a significant percentage of its company's revenues riding on the decision.

The Paul Hastings team was led by New York partners Joseph O'Malley and Bruce Wexler.

About Eisai Co., Ltd. Eisai Co., Ltd. is a research-based human health care 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 more than 9,000 people worldwide.

About Paul Hastings' Litigation Department: The Paul Hastings Litigation Department provides premier litigation services to clients facing complex legal issues in the U.S., Europe, South America, the Middle East and Asia.  With more than 300 lawyers in the Litigation Department, in addition to 200 litigators in the Employment Department, Paul Hastings is well positioned to handle all aspects of a client's litigation needs. Our sophisticated litigation practice covers every major practice including securities, intellectual property, class action and employment litigation, international arbitration, and white-collar crime. The Litigation Department has an impressive track record of winning large and difficult cases.

Paul Hastings Janofsky & Walker LLP, founded in 1951, is a leading international law firm with over 1,200 attorneys in 18 offices. The firm serves a diverse client base including many of the leading global financial institutions and Fortune 500 companies and offers deep capabilities in banking and finance, capital markets, corporate/M&A, litigation and dispute resolution, intellectual property, project finance, investment management, real estate, labor and employment and tax advisory services. For additional information, please visit our website at




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