n the only precedential opinion this week, Teva Pharmaceuticals USA, Inc. v. Eisai Co, the CAFC considered a dismissal of a declaratory judgment action. Eisai owns five patents for donepezil hydrochloride (“donepezil’), an approved treatment for Alzheimer’s disease. Teva had filed an ANDA (Abbreviated New Drug Application) for a form of donepezil covered by four of the five patents. As part of the ANDA, Teva had to assert that the patents for donepezil listed in the FDA’s Orange Book were either invalid or not infringed. The five patents for donepezil owned by Eisai are listed in the FDA’s Orange Book. Prior to the action that led to this case, Eisai filed a statutory disclaimer canceling all of the claims in two of the four patents involved in this case. Teva filed, in District Court, for a declaratory judgment of non-infringement with regard to the four patents of interest. Eisai and Teva subsequently signed a covenant not to sue on the two patents for which the claims had not been canceled; however, all four patents remained listed in the FDA’s Orange Book. The District Court dismissed the declaratory judgment action since there was no longer any controversy, in view of the canceled claims and a covenant not to sue. The CAFC reversed the dismissal since, in the absence of a declaratory judgment for the four patents listed in the FDA’s Orange Book, Teva could not proceed with the ANDA.