A judge in the United States District Court for the District of Delaware has found infringement by Liquidia of two claims included in US Patent No. 11,826,327 (“Treatment for interstitial lung disease”), which was issued to United Therapeutics in 2023. Liquidia says that it now intends to submit an sNDA to remove the pulmonary hypertension associated with interstitial lung disease (PH-ILD) indication from the label for its Yutrepia treprostinil DPI.
Yutrepia was tentatively approved by the FDA in November 2021 for the treatment of pulmonary arterial hypertension (PAH) and the agency tentatively approved an sNDA to add the PH-ILD indication in 2024. The FDA issued final approval of Yutrepia for both indications in May 2025. United Therapeutics, whose Tyvaso inhalation solution has been approved for the treatment of PAH since 2009 and for PH-ILD since 2021, submitted an NDA for Tyvaso DPI in April 2021, and that DPI was approved for both the PAH and PH-ILD indications in May 2022.
United Therapeutics says that it has asked the judge to require the FDA to withdraw approval of the Yutrepia NDA for both indications, which could result in the DPI being removed from the market “until such time as FDA can approve labeling omitting the PH-ILD indication.” The company said that it is also asking for monetary damages such as royalties on previous sales of Yutrepia.
United Therapeutics filed suit against Liquidia in June 2020, alleging infringement of US Patent No. 9,604,901 and US Patent No. 9,593,066 after the FDA accepted Liquidia’s NDA for Yutrepia for the treatment of PAH. In July 2020, US Patent No. 10,716,793 was issued to United Therapeutics, and the company then added claims related to infringement of that patent to the suit. In 2022, a judge ruled that the claims in the ‘066 patent were either invalid or not infringed. In December 2023, the US Court of Appeals upheld a decision by the Patent Trial and Appeal Board (PTAB) invalidating all of the claims of US Patent No. 10,716,793.
Litigation continued, with United Therapeutics adding claims related to infringement of the ‘327 patent in late 2023. In addition to suing Liquidia for patent infringement, United Therapeutics, United Therapeutics also sued the FDA alleging that its handling of the sNDA to add the PH-ILD indication to Yutrepia was inappropriate.
United Therapeutics President and Chief Operating Officer Michael Benkowitz commented, “We are pleased with the Court’s decision, which reinforces our significant research and commitment to bring innovative therapies to the patients we serve. Our immediate priority is ensuring that no patient goes without the therapy they need, and we are ready to support a seamless transition to Tyvaso or Tyvaso DPI should PH-ILD be removed from the Yutrepia label. We look forward to working closely with patients, prescribers, and all other stakeholders throughout this process.”
Liquidia CEO Roger Jeffs said, “We respectfully disagree with the Court’s decision regarding claims 1 and 14 and are fully prepared to pursue all available appellate options. As previously communicated to the Court, we intend to submit a supplement to Yutrepia’s New Drug Application to the FDA to remove PH-ILD from the label. Our commitment to patients remains unwavering.”
Read the United Therapeutics press release
Read the Liquidia press release
