Eisai said that it believes that its patent covering the composition of donepezil, the active ingredient in Aricept, is valid until its expiration date of November 25, 2010, and that it intends to “vigorously enforce and defend the patent.”
Aricept is an acetylcholinesterase inhibitor and is believed to work by inhibiting the breakdown of acetylcholine, thereby increasing available levels of this chemical in the brain.
Separately, Eisai also recently announced that it has come to an agreement with Israeli drug maker Teva to end a collaboration focused on the Parkinson’s drug rasagiline (Azilect).