Silver Spring, Maryland & Research Triangle Park, North Carolina — August 17, 2026
United Therapeutics Corporation announced the full enrollment of its TETON-PPF Phase 3 study evaluating Tyvaso® (treprostinil) inhalation solution in patients with progressive pulmonary fibrosis (PPF). The multinational registration study enrolled 754 patients and is designed to evaluate the safety and efficacy of nebulized Tyvaso over a 52-week treatment period. The company expects topline data in the second half of 2027, making the enrollment milestone an important step in the development of inhaled treprostinil for PPF. If successful, United Therapeutics intends to use the study results to support a supplemental New Drug Application (sNDA) to the U.S. Food and Drug Administration to add PPF to the labeled indications for nebulized Tyvaso. Tyvaso is currently investigational for PPF.
TETON-PPF Completes Enrollment With 754 Patients
The TETON-PPF study is a randomized, double-blind, placebo-controlled Phase 3 trial evaluating nebulized Tyvaso in patients with progressive pulmonary fibrosis. Participants were randomized 1:1 to receive Tyvaso or placebo, beginning with three breaths four times daily and titrating toward a target of 12 breaths four times daily, as tolerated. The primary endpoint is the change in absolute forced vital capacity (FVC) from baseline to Week 52, an important measure of lung function. Secondary assessments include time to first clinical worsening, acute exacerbation of interstitial lung disease, overall survival, percent-predicted FVC, health-related quality of life and diffusing capacity of the lungs for carbon monoxide. The study’s full enrollment in August 2026 positions United Therapeutics to continue follow-up and data collection ahead of the anticipated topline readout in the second half of 2027.
United Therapeutics Targets Progressive Pulmonary Fibrosis
Progressive pulmonary fibrosis is a serious form of interstitial lung disease characterized by ongoing and self-sustaining lung fibrosis that can lead to declining lung function, reduced quality of life and increased mortality. PPF can develop across several underlying interstitial lung diseases, including idiopathic interstitial pneumonias, autoimmune-associated ILDs, chronic fibrosing hypersensitivity pneumonitis and fibrotic lung disease linked to environmental or occupational exposure. United Therapeutics estimates that approximately 200,000 people in the United States have PPF, highlighting a substantial potential patient population. The company is investigating inhaled treprostinil because of similarities in the mechanisms of fibrosis observed between PPF and idiopathic pulmonary fibrosis. However, the effectiveness of nebulized Tyvaso specifically in PPF remains unproven and investigational, with the TETON-PPF results expected to determine whether the treatment can demonstrate a meaningful effect on lung function and disease progression.
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Tyvaso Development Expands Beyond Existing Indications
The TETON-PPF program forms part of United Therapeutics’ broader development strategy for Tyvaso, an inhaled formulation of treprostinil. Tyvaso is currently approved for pulmonary arterial hypertension (PAH) to improve exercise ability and for pulmonary hypertension associated with interstitial lung disease (PH-ILD). United Therapeutics is also pursuing an sNDA to add idiopathic pulmonary fibrosis (IPF) to the labeled indications for nebulized Tyvaso based on results from the TETON-1 and TETON-2 studies. The company is currently seeking priority review of that application, which was submitted to the FDA in June 2026. Meanwhile, TETON-PPF will generate additional clinical evidence for inhaled treprostinil in a broader fibrotic lung disease population. The program’s next major milestone will be the 2027 topline data, which will determine whether United Therapeutics can advance the PPF indication toward regulatory review.
Source: United Therapeutics press relese
