On Dec. 20, 2023, Federal Circuit affirmed PTAB decision that claims 1–8 of US 10,716,793 are unpatentable.

United Therapeutics Corporation owns the ’793 patent, which is directed to methods of treating pulmonary hypertension comprising inhalation of treprostinil with single dose from 15 micrograms to 90 micrograms delivered in 1 to 3 breaths. Dependent claims mention specific dry powder and particle size. Liquidia Technologies, Inc. petitioned for IPR of all claims of the ’793 patent, asserting that they would have been obvious over, US 6,521,212, in view of Voswinckel JESC (“JESC”) and Voswinckel JAHA (“JAHA”) abstracts. The ’212 patent, an unrelated patent owned by UTC, is directed to methods of delivering benzindene prostaglandins, such as treprostinil sodium, to
patients via inhalation to treat pulmonary hypertension. JESC is an abstract that describes a study in which patients inhaled solutions of treprostinil in concentrations of 16, 32, 48, and 64 μg/mL via a nebulizer.  JAHA is an abstract that describes a study in which patients inhaled solutions of treprostinil sodium via a nebulizer in 3 single breaths. Before the Board, UTC challenged the prior art status of the Voswinckel abstracts, arguing that Liquidia had failed to adequately show that those references qualified as “printed publications” under pre-AIA 35 U.S.C. § 102(b). Liquidia asserted that each abstract had been presented at a public conference and that they were both cited in other documents dating from before the priority date of the ’793 patent. Board agreed with Liquidia and found claims unpatentable.

On appeal, Federal Circuit agreed with Board with respect to abstracts and said that the Voswinckel abstracts were sufficiently disseminated such that each constituted a printed publication was supported by substantial evidence. Court also said that although no reference explicitly taught the dose, the person of ordinary skill in the art would have understood the solutions in JESC to have delivered an amount of treprostinil within the claimed range. JESC discloses the administration of treprostinil solution via a nebulizer to patients in concentrations of 16, 32, 48, and 64 μg/mL. Based on delivery volumes (1 to 5 mL), the amounts of treprostinil delivered in JESC would have been from 16–80, 32–160, 48–240, or 64–320 μg, each of which has at least one endpoint that falls within the claimed range of 15–90 μg. With respect to dry powder limitations in the dependent claims, UTC argued that none of the ‘212 patent, JESC, or JAHA discloses any dry powder dosages. Court said that the ’212 patent, which is also owned by UTC, discloses the use of an “inhaler,” and that “solid formulations, usually in the form of a powder, may be inhaled in accordance with the present invention.” It also teaches that such formulations have particle sizes of preferably less than 5 micrometers in diameter. The Board correctly relied not only on these disclosures, but also on the unrebutted testimony of Liquidia’s expert that a person of ordinary skill in the art would have had a reasonable expectation of success in arriving at the claimed dry powder formulation based on the combined teachings of the ’212 patent, JESC, and JAHA. Thus, Federal Circuit affirmed Board’s unpatentability determination.