INTELLECTUAL PROPERTY HIGH COURT OF JAPAN RULES TO MAINTAIN ARICEPT® PATENT TERM EXTENSION IN RELATION TO SEVERE ALZHEIMER'S DEMENTIA

Eisai Co., Ltd. (Headquarters: Tokyo, President & CEO: Haruo Naito) today announced that the Intellectual Property High Court of Japan has issued its ruling to maintain the decision of the Japan Patent Office to grant an extension for the Aricept® (donepezil hydrochloride) patent in relation to severe Alzheimer's dementia.

Eisai filed for the extension in relation to the use of Aricept® for severe Alzheimer's dementia based on the additional approval of its efficacy and dosage for the disorder granted by the Ministry of Health, Labor and Welfare of Japan in August, 2007. As a result, the term of the patent was extended until June 22, 2013.

A number of generic drug manufacturers responded to this by initiating an invalidation trial, but the Japan Patent Office handed down its decision to maintain the patent term extension on November 25, 2009. The generic drug manufacturers subsequently petitioned the Intellectual Property High Court to annul this decision on December 24, 2009. The High Court has now accepted Eisai's arguments and has issued its ruling to maintain the decision of the Japan Patent Office in relation to the patent invalidation trial for the extension in question.

Eisai will continue to make further contributions to increase the benefits provided to patients and their families as well as healthcare professionals.

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Public Relations Department,
Eisai Co., Ltd.
+81-(0)3-3817-5120