United Therapeutics Corporation (Nasdaq: UTHR) announced that the U.S. Food and Drug Administration has accepted a supplemental New Drug Application for nebulized Tyvaso (treprostinil) Inhalation Solution to treat idiopathic pulmonary fibrosis (IPF).

The company said it anticipates the FDA's review will be complete in late April 2027. Nebulized Tyvaso has not been approved by the FDA for IPF and remains investigational for this indication.

The application was based on results from the phase 3 TETON-1 and TETON-2 studies. Combined analyses of the two trials met the primary efficacy endpoint, with nebulized Tyvaso showing statistically significant superiority over placebo in the change in absolute forced vital capacity by 111.8 mL from baseline to week 52.

The combined analyses also showed statistical significance for most key secondary endpoints, including reduced risk of clinical worsening, reduced risk of acute IPF exacerbation, and changes in percent of predicted forced vital capacity, quality of life scores, and diffusion capacity of lungs for carbon monoxide.

TETON-1 data were presented at the 2026 annual meeting of the American Thoracic Society, while TETON-2 data were published in The New England Journal of Medicine. Combined results from both studies were presented at the same conference and simultaneously published in The New England Journal of Medicine.

Both the FDA and the European Medicines Agency have granted orphan designation for treprostinil to treat IPF.

United Therapeutics estimates that at least 100,000 people in the United States are living with IPF, a progressive scarring disease of the lungs that can lead to respiratory failure.