In re Gosteli
Court of Appeals for the Federal Circuit
872 F.2d 1008 (1989)
Gosteli's (applicant) U.S. patent application claiming antibiotic compounds was rejected based on the Menard patent, which was filed in the U.S. before Gosteli's application and disclosed the same compounds; Gosteli sought to claim an earlier priority date through a previously filed, less thorough Luxembourg application predating Menard's U.S. filing, but the Board of Patent Appeals and Interferences found the Luxembourg filing did not fully support Gosteli's U.S. claims and therefore could not serve as a priority document, meaning Menard remained valid prior art. Gosteli appealed, also arguing he could show actual reduction to practice before Menard's priority date.
Whether an earlier-filed foreign patent application that fails to fully support a later-filed domestic patent application's claim can properly serve as a priority document granting an earlier effective priority date to the domestic application.