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Last week, the Federal Circuit issued a precedential decision in <a href="https://cafc.uscourts.gov/opinions-orders/22-2217.OPINION.7-24-2023_2161663.pdf"><em>United Therapeutics Corp. v. Liquidia Technologies, Inc.</em>, No. 22-2217 (July 24, 2023)</a>. The Court affirmed the district court’s holding that the pulmonary hypertension (“PH”) patents at issue were not invalid for lack of enablement.

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United Therapeutics sued Liquidia for infringing U.S. Patent 10,716,793 (the ’793 patent) and U.S. Patent 9,593,066 (the ’066 patent). The ’793 patent claims a method of administering the drug treprostinil via an inhaled solution. The ’066 patent claims a pharmaceutical composition of treprostinil. The district court found the method patent was valid and infringed by Liquidia but the composition patent was invalid as anticipated. Consequently, the New Drug Application for Liquidia’s treprostinil drug, Yutrepia, was denied until expiration of the ’793 patent. Both parties appealed.

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The Federal Circuit affirmed the district court’s decision on all grounds. With respect to the ’066 composition patent, the Court affirmed the district court’s holding that certain claims are invalid and thus, not infringed.

With respect to the ’793 method patent, the Court likewise affirmed the district court’s holding that Liquidia would induce infringement by marketing Yutrepia and that Liquidia failed to prove any claim of the ’793 patent invalid as not enabled. &nbsp;The Court noted that the claim term “treating pulmonary hypertension” includes treating five subset groups of PH patients. Liquidia argued the specification of the ’793 patent provides no guidance on how to treat a specific subset of patients (Group 2 PH), and thus was not enabled for Group 2 PH patients. The Court disagreed, stating:

… It would be incorrect to fractionate a disease or condition that a method of treatment claim is directed to, and to require a separate disclosure in the specification for each individual variant of the condition (here, an individual group of pulmonary hypertension patients) in order to satisfy the enablement and written description provisions of 35 U.S.C. § 112, unless these variants are specified in the claims.

The Court explained that a subset of patients is not analogous to an unsupported species in a generic claim to chemical compounds.

The Court also rejected Liquidia’s argument that the claim term “treating pulmonary hypertension” requires a showing of safety and efficacy, noting that absent claim limitations incorporating safety and efficacy requirements “[q]uestions of safety and efficacy in patent law have long fallen under the purview of the FDA.”

CAFC Holds Separate Disclosure of Drug Variants Not Required Under Section 112

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