United Therapeutics files patent infringement suit against Liquidia over YUTREPIA

United Therapeutics Corporation (UTHR) filed a patent infringement complaint against Liquidia Corporation (Nasdaq: LQDA) on May 9, 2025, according to a Form 8-K that Liquidia filed on May 12, 2025. Liquidia is the only defendant named in the filing and in the company's press release. The case is pending in the U.S. District Court for the Middle District of North Carolina, Case No. 1:25-cv-00368.

The complaint alleges that Liquidia infringes U.S. Patent No. 11,357,782, the '782 patent, which issued on June 14, 2022. It also seeks to enjoin Liquidia from commercializing YUTREPIA (treprostinil) inhalation powder if the U.S. Food and Drug Administration approves it for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD). These are allegations by UTHR. No court has ruled on them.

What the filing says

The 8-K, signed by Chief Financial Officer and Chief Operating Officer Michael Kaseta, reports the suit under Item 8.01 and attaches a press release issued the same day.

The FDA has set a Prescription Drug User Fee Act goal date of May 24, 2025 for the New Drug Application for YUTREPIA. The 8-K says UTHR is currently not seeking any injunction against the FDA to prevent final approval of that application, and that the suit does not affect the FDA's ability to act on the goal date.

Liquidia's response

Liquidia says the '782 patent comes from the same patent family as U.S. Patent No. 10,716,793, the '793 patent, and claims the same general method of administering inhaled treprostinil to pulmonary hypertension patients. It says the Patent Trial and Appeal Board held the '793 patent invalid, as disclosed in July 2022. It says the U.S. Court of Appeals for the Federal Circuit affirmed that decision in December 2023, and that the United States Supreme Court rejected UTHR's petition for a writ of certiorari.

The release adds a caution: the invalidity of one patent is not necessarily determinative of the validity of a second patent, even one from the same family or with similar claims. That caveat cuts against Liquidia's own argument, since the company is relying on the earlier ruling.

Dr. Roger Jeffs, Liquidia's chief executive, said in the release: "We have invalidated similar claims covering the treatment of pulmonary hypertension patients with inhaled treprostinil in the past." The company says it will keep defending patients' rights. Those are the company's words, and the release does not present any new court finding on the '782 patent.

What is not in the filing

The 8-K and release give no date for the court's schedule, no claim construction, and no sign of when a ruling might come. They do not say how much of Liquidia's revenue or planned launch depends on YUTREPIA, and they do not describe the relief UTHR would receive beyond the injunction request. The release lists no hearing or trial date.

Company background

Liquidia Corporation is a Delaware corporation headquartered in Morrisville, North Carolina. The release describes the company as focused on rare cardiopulmonary diseases, including PAH and PH-ILD. It also says the company is developing L606, an investigational formulation of treprostinil.

People named in the filings

Michael Kaseta signed the 8-K on May 12, 2025. Jason Adair, Chief Business Officer, is the investor contact in the release.

What comes next

The FDA goal date of May 24, 2025 is the next fixed date in the filings. The complaint is at an early stage, and the 8-K gives no timetable for a court ruling on the '782 patent. Until then, the allegations stand as UTHR's claims, and Liquidia's defence rests on the earlier invalidity ruling.

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