Tyvaso met the primary endpoint in the Phase 3 TETON-1 trial, improving lung function and reducing disease worsening in IPF, with results exceeding prior TETON-2 findings.
Written By: Mahathi Palivela, PharmD
Reviewed By: Pharmacally Editorial Team
United Therapeutics has reported positive topline results from the pivotal TETON-1 Phase 3 study (NCT04708782), with nebulized Tyvaso® (treprostinil) demonstrating a statistically significant and clinically meaningful improvement in lung function in patients with idiopathic pulmonary fibrosis (IPF). The study met its primary endpoint, showing a 130.1 mL improvement in absolute forced vital capacity (FVC) versus placebo at week 52 (p<0.0001).
Martine Rothblatt, Chairperson and Chief Executive Officer of United Therapeutics said TETON-1 outperformed TETON-2 and represents a meaningful advance for IPF patients, while highlighting that multiple recent Phase 3 successes reflect strong pipeline momentum and continued innovation in rare cardiopulmonary diseases.
The TETON-1 results exceeded the already positive outcomes observed in the TETON-2 trial, further strengthening the evidence base for Tyvaso in IPF. In addition to the primary endpoint, the therapy significantly reduced the risk of clinical worsening and showed favorable trends across key secondary endpoints, including time to acute exacerbations, quality of life (K-BILD score), and lung diffusion capacity (DLCO).
Benefits were consistent across patient subgroups, including those receiving background antifibrotic therapies such as nintedanib or pirfenidone, as well as across smoking status and oxygen use. The safety profile remained consistent with prior experience, with no new safety signals identified.
A pooled analysis of TETON-1 and TETON-2 further confirmed the robustness of the findings, demonstrating a statistically significant improvement in FVC of 111.8 mL compared with placebo (p<0.0001), along with benefits across multiple secondary endpoints. While overall survival at 52 weeks numerically favored Tyvaso, it did not reach statistical significance.
Tyvaso is a prostacyclin mimetic delivered directly to the lungs via inhalation. Its multimodal mechanism targets fibrotic, vascular, and inflammatory pathways, offering a differentiated approach compared with currently available IPF therapies that primarily focus on fibrosis alone.
Based on the combined TETON-1 and TETON-2 data, United Therapeutics plans to submit a supplemental New Drug Application (sNDA) to the U.S. FDA by mid-2026, seeking approval to expand Tyvaso’s label to include IPF. The company intends to request priority review. Both U.S. and European regulators have already granted orphan designation for treprostinil in this indication.
Additional detailed results from TETON-1 and the integrated analyses will be presented at the American Thoracic Society Annual Meeting in May 2026.
Steven D. Nathan Schar Chair, Advanced Lung Disease and Lung Transplant Program at Inova Fairfax Hospital and Chair of the TETON Steering Committee said TETON-1 confirms TETON-2, showing meaningful improvements in lung function, quality of life, and disease progression in IPF, potentially redefining treatment approach.
TETON-1 (NCT04708782) was a 598-patient, randomized, double-blind, placebo-controlled Phase 3 study conducted across the United States and Canada over 52 weeks. The trial evaluated changes in FVC as the primary endpoint, with secondary endpoints assessing disease progression, exacerbations, survival, quality of life, and lung function parameters.
The broader TETON clinical program also includes TETON-2 (global IPF population) and the ongoing TETON-PPF study in progressive pulmonary fibrosis.
Idiopathic pulmonary fibrosis is a progressive and life-limiting lung disease characterized by irreversible scarring of lung tissue, leading to declining respiratory function and eventual respiratory failure. Current treatments provide limited benefit, underscoring the need for more effective therapeutic options.
References
United Therapeutics Corporation Announces Teton-1 Pivotal Study Of Tyvasdoo® Meets Primary Endpoint for Treatment of Idiopathic Pulmonary Fibrosis, Exceeding Impressive Treatment Effect Seen In Teton-2, 30 March 2026, UNITED THERAPEUTICS – A Public Benefit Corporation https://ir.unither.com/press-releases/2026/03-30-2026-120037465
Study of Efficacy and Safety of Inhaled Treprostinil in Subjects with Idiopathic Pulmonary Fibrosis (TETON-1), ClinicalTrials.gov ID NCT04708782, https://clinicaltrials.gov/study/NCT04708782
About the Writer
Mahathi Palivela is pursuing a PharmD and has a strong interest in clinical pharmacy and patient safety. She is passionate about handling and analyzing patient data, and translating clinical insights into clear, meaningful summaries. She aims to apply this interest in medical writing and pharmacovigilance, focusing on improving patient outcomes through careful data interpretation and communication.