United Therapeutics Corporation (Nasdaq: UTHR) has announced the full enrollment of the TETON 1 study, a Phase 3 clinical trial evaluating the safety and efficacy of Tyvaso (treprostinil) inhalation solution for the treatment of idiopathic pulmonary fibrosis (IPF). This milestone marks a significant step forward in the potential development of a new therapy for this progressive and debilitating lung disease.
The TETON 1 study, a multicenter, randomized, double-blind, placebo-controlled trial, enrolled 598 patients across sites in the United States and Canada. It is part of the broader TETON clinical trial program, which includes studies evaluating inhaled treprostinil in both IPF and progressive pulmonary fibrosis (PPF).
TETON Program Aims to Address Unmet Needs in IPF
The TETON program was initiated based on promising data from the INCREASE study, which investigated nebulized Tyvaso for pulmonary hypertension associated with interstitial lung disease (PH-ILD). A post-hoc analysis of the INCREASE study revealed significant improvements in percent predicted forced vital capacity (FVC) at weeks 8 and 16 in patients with IPF treated with nebulized Tyvaso (week 8: 2.5%; p=0.038 and week 16: 3.5%; p=0.015). Furthermore, open-label extension data demonstrated sustained improvements in FVC for at least 64 weeks.
Peter Smith, Pharm. D., Vice President, Product Development at United Therapeutics and the lead for the global TETON program, stated, "Completing enrollment in this trial brings us one step closer to potentially delivering a transformative and much needed treatment option for this vulnerable group of patients living with IPF."
Study Design and Endpoints
In the TETON 1 study, participants were randomized 1:1 to receive either nebulized Tyvaso or a placebo. The primary endpoint is the change in FVC from baseline to week 52. Secondary endpoints include time to clinical worsening, time to first acute exacerbation of IPF, overall survival at week 52, change in percent predicted FVC from baseline to week 52, and change in the King’s Brief Interstitial Lung Disease questionnaire.
Current IPF Treatment Landscape and Future Plans
IPF affects over 100,000 patients in the United States, and currently, there are only two approved therapies, both of which only slow disease progression. If the TETON 1 and TETON 2 trials yield positive results, United Therapeutics intends to file for FDA approval to include IPF as an indication for nebulized Tyvaso. In Europe, the company plans to collaborate with Grupo Ferrer Internacional, S.A. to seek marketing authorization from the European Medicines Agency (EMA) for nebulized Tyvaso in the treatment of IPF.
Top-line data from the TETON 1 study is expected in the first half of 2026. The TETON 2 study, which completed enrollment in July 2024, is anticipated to release top-line data in the second half of 2025. Enrollment in the TETON PPF study is ongoing.
