United Therapeutics Corporation (Nasdaq: UTHR) has initiated legal action against the United States Food and Drug Administration (FDA), as announced today. The litigation centers on United Therapeutics’ claim that the FDA erroneously allowed Liquidia Corporation (Liquidia) to circumvent established FDA regulations, precedents, and protocols concerning the handling of pending drug approval applications. This alleged mishandling by the FDA resulted in the improper denial of United Therapeutics’ request for a stay on the final approval granted to Liquidia, pending the resolution of United Therapeutics’ pending patent infringement claim against Liquidia.
This legal action pertains to the FDA’s handling of Liquidia’s amendment to a pending new drug application (NDA) aimed at adding a second indication, pulmonary hypertension associated with interstitial lung disease (PH-ILD), to its proposed inhaled dry powder treprostinil product’s label. United Therapeutics contends in the lawsuit that FDA regulations, precedents, and procedures dictate that Liquidia should have sought approval for this second indication by submitting a new NDA rather than amending a pending one. United Therapeutics argues that this distinction is crucial to ensure the proper review and approval of new drug applications in a manner consistent with the FDA’s historical practices that the industry has followed for decades.
Prior to 2021, all clinical trials of drugs approved for pulmonary hypertension treatment, but studied for PH-ILD treatment, had failed. Some approved pulmonary hypertension therapies even worsened patients’ condition, leaving PH-ILD without any approved treatments.
Despite the documented failures in PH-ILD treatment by others, United Therapeutics conducted an innovative pivotal trial of Tyvaso® (treprostinil) Inhalation Solution for PH-ILD treatment, at considerable expense. This trial, named INCREASE, was the largest and most comprehensive study of its kind, leading to Tyvaso’s approval as the first-ever PH-ILD treatment by the FDA in March 2021. The successful results of the INCREASE study were published in The New England Journal of Medicine in January 2021.
Under the Hatch-Waxman Act, when a company like Liquidia seeks approval that relies on another drug’s prior approval and may infringe patents listed for that drug, a timely filed patent infringement action can delay the FDA’s approval of the NDA for up to 30 months or until the litigation’s resolution, whichever comes first. By amending its existing NDA instead of filing a new one, Liquidia avoided a 30-month approval delay for PH-ILD, despite relying on United Therapeutics’ prior approval for Tyvaso. United Therapeutics aims to ensure fair treatment for true pharmaceutical and biotech innovators by seeking correct and consistent interpretation of FDA rules, precedents, and procedures through this lawsuit. If successful, United Therapeutics’ litigation could prevent final approval for Liquidia’s PH-ILD indication for up to 30 months, allowing time for separate patent litigation to conclude.
Dean Bunce, Executive Vice President of Global Regulatory Affairs at United Therapeutics, commented, “The FDA is a global leader in public health, but sometimes legal and regulatory precedents are overlooked. We simply ask that the FDA apply its own rules and precedents consistently to uphold the balance between innovators and imitators as mandated by the Hatch-Waxman Act: Liquidia can benefit from United Therapeutics’ innovation to expedite its market entry, but must address the infringement claim before rushing to market.”
United Therapeutics previously sued Liquidia for infringing U.S. Patent No. 11,826,327 (the ‘327 patent) due to its efforts to obtain approval for the PH-ILD indication. The ‘327 patent’s claims generally revolve around improving exercise capacity in PH-ILD patients by inhaling treprostinil at specific dosages. This patent infringement case is currently pending in the U.S. District Court for the District of Delaware.
