United Therapeutics Corp. v. Liquidia Technologies, Inc., Nos. 2022-2217, 2023-1021 (Fed. Cir. (D. Del.) July 24, 2023). Opinion by Lourie, joined by Dyk and Stoll.
United Therapeutics sued Liquidia for infringement of two patents related to methods of treating pulmonary hypertension and to pharmaceutical compositions comprising treprostinil, which is used in treating pulmonary hypertension.
Regarding the first patent, the district court held that all asserted claims were not proved invalid and were infringed by Liquidia. Meanwhile, in a parallel IPR proceeding, the Patent Trial and Appeal Board issued a final written decision finding all challenged claims unpatentable as obvious. United Therapeutics appealed that decision, and the appeal remains pending at the Federal Circuit. Regarding the second patent, the district court held that certain claims were invalid as anticipated (but otherwise infringed) while other claims were invalid and/or not infringed.
Liquidia appealed and United Therapeutics cross-appealed, with each party challenging the associated adverse rulings. The Federal Circuit affirmed the district court’s judgment in full.
Liquidia first argued that the district court erred by construing the term “treating pulmonary hypertension” not to require a showing of safety and efficacy. The Federal Circuit agreed with United Therapeutics that nothing in the patent specification required importing safety and efficacy limitations into the claims. Also, the claims separately recited a “therapeutically effective” dose of treprostinil, and Liquidia did not challenge the construction of that term. Still further, the Federal Circuit explained that “questions of safety and efficacy in patent law have long fallen under the purview of the FDA,” and the court “decline[d] to insert the FDA’s responsibility into claims by importing requirements where [the claims] do not recite such limitations.”
Next, Liquidia argued that certain claims were not adequately enabled or supported by a sufficient written description. The Federal Circuit disagreed, ruling that the district court appropriately relied on expert testimony and record evidence to conclude that these requirements were met.
The Federal Circuit also rejected Liquidia’s challenge to the district court’s finding of induced infringement. Liquidia argued that it could not be liable for induced infringement because the Board had found the claims to be unpatentable in an IPR. The Federal Circuit disagreed, stating that “a pending, non-final litigation does not negate an intent to infringe that is otherwise supported by evidence.” In particular, “an IPR decision does not have collateral estoppel effect until that decision is affirmed or the parties waive their appeal rights.” Because the Board’s decision was still pending on appeal, the court ruled that the decision “has no impact” on the question of induced infringement.
Turning to United Therapeutics’s cross-appeal, the Federal Circuit ruled that the district court did not clearly err in finding certain product-by-process claims invalid as anticipated. The court explained that “a product-by-process claim is a product claim, even if claimed by a process by which it can be made.” Here, because “these claims are product claims, they are anticipated by a disclosure of the same product irrespective of the processes by which they are made.”
As to the parties’ remaining challenges, the Federal Circuit ruled that the district court did not clearly err. Thus, the Federal Circuit affirmed in full.