United Therapeutics Corporation (Nasdaq: UTHR) announced it has completed enrollment in its TETON-PPF phase 3 clinical trial, which is evaluating inhaled treprostinil, sold under the brand name Tyvaso, as a treatment for progressive pulmonary fibrosis (PPF).

The study enrolled 754 patients across multiple countries and reached full enrollment in August 2026. Topline data are expected in the second half of 2027. The trial is a randomized, double-blind, placebo-controlled study assessing the safety and efficacy of nebulized Tyvaso over a 52-week period. The primary endpoint is the change in absolute forced vital capacity from baseline to week 52.

If the trial produces positive results, United Therapeutics said it intends to submit a supplemental New Drug Application (sNDA) to the U.S. Food and Drug Administration to add PPF to the approved indications for nebulized Tyvaso. The drug has not been approved by the FDA for PPF and remains investigational for this use.

The company is separately seeking priority FDA review of an sNDA filed in June 2026 to add idiopathic pulmonary fibrosis (IPF) to Tyvaso's labeled indications, based on data from the earlier TETON-1 and TETON-2 studies, which were published in the New England Journal of Medicine.

PPF is estimated to affect approximately 200,000 patients in the United States. The condition is characterized by progressive lung scarring, reduced lung function, and elevated mortality. Estimated median transplant-free survival is approximately 2.9 years, with overall survival of approximately 3.7 years.

According to a company statement, participants in the TETON-PPF study were randomized 1:1 to receive nebulized Tyvaso or placebo, starting at three breaths four times daily and titrating to a target of 12 breaths four times daily. Patients who complete the 52-week visit may be eligible for an open-label extension study.