Liquidia Loses Bid to Dismiss United Therapeutics Patent Lawsuit Over Yutrepia Lung Drug
Key Insights
A federal judge denied Liquidia Corp. (search)'s motion to dismiss United Therapeutics Corp.'s patent infringement lawsuit over the lung disease drug Yutrepia (search), ruling that the claims don't constitute serial litigation.
The current case involves U.S. Patent No. 11,357,782, which differs materially from the previously litigated U.S. Patent No. 10,716,793, preventing application of claim or issue preclusion defenses.
Yutrepia (search) is a dry powder formulation of treprostinil used to treat pulmonary diseases (search), with Liquidia seeking FDA approval through an NDA filing that referenced UTC's Tyvaso product.
A federal judge has denied Liquidia Corp. (search)'s motion to dismiss United Therapeutics Corp.'s patent infringement lawsuit over the lung disease drug Yutrepia (search), finding that the claims don't qualify as prohibited serial litigation. Judge Thomas D. Schroeder of the U.S. District Court for the Middle District of North Carolina ruled Tuesday that sufficient differences exist between the current case and previous litigation to allow the lawsuit to proceed.
Patent Dispute Centers on Different Claims
The current lawsuit involves U.S. Patent No. 11,357,782, while earlier litigation focused on U.S. Patent No. 10,716,793. Judge Schroeder determined there isn't enough overlap between the cases' allegations to warrant dismissal under issue or claim preclusion doctrines.
Yutrepia (search) is a dry powder formulation of treprostinil used to treat certain pulmonary diseases (search). In January 2020, Liquidia filed a New Drug Application (NDA) seeking FDA approval to manufacture and sell the drug, referencing UTC's Tyvaso product and filing Paragraph IV Certifications for patents listed in the Orange Book covering Tyvaso.
Complex Litigation History
The patent dispute has a complicated history spanning multiple lawsuits. UTC first sued Liquidia in June 2020, alleging infringement of the '793 patent. While a court initially found that Yutrepia (search) infringed that patent, the decision was later vacated after the Patent Trial and Appeal Board (PTAB) ruled the '793 patent claims were unpatentable.
In July 2023, Liquidia amended its NDA for Yutrepia (search) to add pulmonary hypertension (search) associated with interstitial lung disease (search) as an indication. UTC sued again over the '793 patent, but the parties stipulated to dismiss the claim after the Federal Circuit affirmed the PTAB's unpatentability decision.
Current Case Involves Non-Orange Book Patent
UTC filed the current lawsuit in May 2025, alleging infringement of the '782 patent, which it had not previously asserted. Notably, the '782 patent was not listed in the Orange Book because it claims a dry powder inhaler, while Tyvaso uses a nebulized mist inhalation device.
Rather than pursuing claims under the typical Hatch-Waxman framework, UTC sued under different provisions of patent law and the Declaratory Judgment Act. The company's lawsuit arose in response to Liquidia's public announcement of its plan to launch Yutrepia (search).
Court Rejects Multiple Defense Arguments
Liquidia attempted to dismiss the case on several grounds, including claim-splitting, the first-filed rule, claim preclusion, issue preclusion, and the Kessler doctrine. The court systematically rejected each argument.
Regarding claim preclusion, Judge Schroeder found that Liquidia had not demonstrated sufficient overlap between the '782 and '793 patents to conclude they are "essentially the same" at the Rule 12 stage. The court noted that the present suit did not arise from the same transaction or series of transactions as the previous Hatch-Waxman suits.
Material Differences Between Patents
The court identified key differences between the patents that prevented application of issue preclusion. Specifically, the '782 patent contemplates an additional dose administered at least three hours after the first dose, while the '793 patent's claims make no mention of an additional dose event.
Similarly, the court found that Liquidia had not demonstrated that the '793 and '782 patents are sufficiently indistinguishable to trigger the Kessler doctrine's bar against serial litigation, despite involving the same parties and accused product.
The ruling allows UTC to proceed with its patent infringement claims against Liquidia's Yutrepia (search) product under the '782 patent, setting the stage for continued litigation between the companies over this lung disease treatment.