Eisai Mistake Allows Dismissal in Donepezil ODT Case

On December 20, 2007, the District Court in New Jersey granted Mutual’s Motion to Dismiss. Apparently, when Mutual filed its ANDA, there were no patents listed in the Orange Book. When Eisai submitted patents for Orange Book listing for the ODT product, it mistakenly filled out the forms (3542a instead of 3542) with the NDA number and product name of the tablet formulation, so FDA did not list any patents for ODT. As such, Mutual had no patents to certify against, and Eisai sued Mutual anyway for infringement of the sole Orange Book patent US4895841 (which covers Donepezil as product and also covers method of use in senile dementia of the Alzheimer type). In its press release, Eisai implies that they have reached an agreement (perhaps in lieu of an appeal of this decision as reported earlier in this blog) that Mutual will give Eisai 45 days notice before it launches. While the patent expires in 2010, there is a likelihood that Mutual will be approved before then, and if it decides to launch, expect to see a preliminary injunction filed by Eisai.