In a Hatch-Waxman litigation, the patentee alleged infringement of its patent covering a reformulation of its antidote for acetaminophen overdose. The improved formulation no longer contained edetate disodium (EDTA)—a chelating agent used to keep the antidote from degrading. During the approval process for the original antidote, the FDA sought the patentee’s justification for adding EDTA to its formulation. This request purportedly prompted the patentee’s idea for a formulation without EDTA, which it then discussed with the FDA. The FDA requested that the patentee conduct stability studies on the effects of reducing or eliminating EDTA. After completing these studies, the patentee discovered that the antidote was stable without EDTA or any other chelating agent. The resulting invention was the subject matter of the patent-in-suit, which claims a composition “free of chelating agents.” The accused infringer stipulated to infringement but asserted that the patent was invalid because the idea to remove EDTA derived from the FDA rather than the named inventor and because the invention would have been obvious in light of prior-art communications from the FDA. Following a bench trial, the district court rejected both arguments and found the patent valid. The accused infringer appealed.

The Federal Circuit affirmed the district court’s finding of validity. The Federal Circuit found that the accused infringer failed to show derivation under 35 U.S.C. §102(f) because it could not show, by clear and convincing evidence, that someone at the FDA conceived of “all limitations of the claimed invention.” The Federal Circuit found that the FDA’s request for data to support the inclusion of EDTA in the original product did not amount to a suggestion to remove EDTA, let alone to remove it and not replace it with another chelating agent. Because the claims require a composition free from any chelating agent and there was no evidence that the FDA requested testing of a chelating agent-free formulation, the Federal Circuit found the accused infringer had not established derivation from the FDA.

The Federal Circuit also rejected the accused infringer’s argument that the EDTA-free antidote would have been obvious in light of the label for the original antidote, the communications from the FDA requesting studies on reduced or eliminated EDTA, and a prior art reference. The Federal Circuit held that the district court did not err in finding that there was no reasonable expectation of success that a chelating agent free formulation would be stable where numerous prior art references taught that the composition would be unstable without EDTA.