Eisai to submit NDA for Aricept in Aug or Sept

TOKYO, July 2 (Reuters) - Japanese drugmaker Eisai Co Ltd (4523.T) said on Thursday it plans to submit a new drug application (NDA) with the U.S. Food and Drug Administration on a new form of its key Alzheimer's disease drug Aricept in August or September.

The drug, with the active ingredient donepezil, accounts for nearly 40 percent of the company's overall sales and faces U.S. patent expiration in 2010. The company has been seeking to apply its new formulations and uses to fend off potential generic competition.

The company said in a statement that it has completed a phase three clinical study of donepezil sustained release, a formulation that raises the blood level of donepezil while maintaining safety. (Reporting by Taiga Uranaka; Editing by Hans Peters)