The U.S. Court of Appeals for the Federal Circuit recently confirmed that to qualify as joint inventors under 35 U.S.C. § 116, each contributor need not have an independent mental picture of the complete chemical compound claimed, but must contribute to the “joint arrival at a definite and permanent idea of the invention as it will be used in practice.” Vanderbilt University v. ICOS Corp., Case No. 09-1258 (Fed. Cir., Apr. 7, 2010) (Clevenger, J.) (Dyk, concurring in part and dissenting in part).

Vanderbilt filed suit in the U.S. District Court for the District of Delaware against ICOS Corporation under 35 U.S.C. § 256, alleging that three Vanderbilt scientists should be added as joint inventors on certain patents claiming the active ingredient of the drug Cialis, tadalafil. Tadalafil was discovered by a scientist not employed by Vanderbilt, Dr. Alain Claude-Marie Daugan, who is the named inventor on the patents-in-suit.

Vanderbilt claimed that during a collaborative research project with Dr. Daugan’s employer leading up to the discovery of tadalafil, the three Vanderbilt scientists contributed to the selection of compounds to test. ICOS contended that Dr. Daugan and his non-Vanderbilt colleagues independently discovered tadalafil, without any input from Vanderbilt. Vanderbilt presented no direct evidence that its scientists contributed to Dr. Daugan’s ultimate discovery. ICOS presented testimony that Dr. Daugan and his colleagues independently discovered tadalafil.

The district court concluded that Vanderbilt had failed to demonstrate by clear and convincing evidence that its three scientists were joint inventors with Dr. Daugan, explaining that each inventor must have “a mental picture of the structure” of the claimed compound to qualify as a joint inventor under § 116. Vanderbilt appealed.

The Federal Circuit agreed with the district court’s conclusion but not its reasoning. Specifically, the Court noted that the district court erred in its interpretation of § 116, but that Vanderbilt had still failed to meet its evidentiary burden. The Federal Circuit explained that each co-inventor need not have an independent mental picture of the complete claimed compound, writing that, “[i]nstead, a group of co-inventors must collaborate and work together to collectively have a definite and permanent idea of the complete invention.” Nevertheless, finding that Vanderbilt did not produce any direct evidence that its scientists contributed to the discovery of tadalafil, and thus failed to carry its burden of proving joint inventorship by clear and convincing evidence, the Court affirmed the judgment .