01—Abstract
Summary
Summary of the 8-K filed March 30, 2026. Cited figures are marked; the original filing is the authoritative source.
On March 30, 2026, United Therapeutics Corporation (Nasdaq: UTHR) announced that its TETON-1 pivotal phase 3 study of nebulized Tyvaso (treprostinil) Inhalation Solution in idiopathic pulmonary fibrosis (IPF) met its primary endpoint.
Nebulized Tyvaso demonstrated superiority over placebo for the change in absolute forced vital capacity (FVC) of 130.1 mL (Hodges-Lehmann estimate, 95%a CI 82.2 to 178.1 mL; p<0.0001) from baseline to week 52. The study also achieved statistical significance in reducing the risk of clinical worsening, and showed numerical improvement in other secondary endpoints, including time to first acute exacerbation of IPF. The safety profile was described as consistent with prior Tyvaso studies, with no new safety signals.
Integrated analyses of TETON-1 and TETON-2 showed a statistically significant treatment effect on the primary endpoint of 111.8 mL change in absolute FVC (95%b CI 79.7 to 144.0; p<0.0001) and on most secondary endpoints. Overall survival at week 52 trended in favor of Tyvaso but did not reach statistical significance. The company plans to seek priority review of a supplemental New Drug Application, to be submitted to the FDA by the end of summer 2026, to add IPF to Tyvaso's labeled indications.
Additional data will be presented at the American Thoracic Society Annual Meeting in May 2026, and the TETON-PPF study in progressive pulmonary fibrosis is ongoing. The filing is an Item 8.01 (Other Events) report furnishing the press release as Exhibit 99.1. The company's CEO described the results as an inflection point, noting that three pivotal studies (TETON-1, TETON-2, and ADVANCE OUTCOMES for ralinepag) met their primary endpoints in the past seven months.
02—Key points
Key Highlights
- TETON-1 met its primary endpoint: nebulized Tyvaso improved absolute FVC by 130.1 mL versus placebo at week 52 (p<0.0001).
- Statistically significant reduction in the risk of clinical worsening, with numerical improvements in time to first acute exacerbation of IPF, percent predicted FVC, K-BILD, and DLCO.
- Integrated TETON-1 and TETON-2 analyses showed a 111.8 mL FVC treatment effect (p<0.0001) and significance on most secondary endpoints.
- Overall survival at week 52 trended in favor of Tyvaso but did not reach statistical significance.
- Benefits were observed across subgroups, including background therapy (nintedanib, pirfenidone, or none), smoking status, and supplemental oxygen use; no new safety signals were observed.
- United Therapeutics plans to submit a supplemental NDA to the FDA by the end of summer 2026 and seek priority review to add IPF as a labeled indication.
- Both the FDA and the European Medicines Agency have granted orphan designation for treprostinil to treat IPF; TETON-1 and integrated data will be presented at the ATS 2026 meeting in May.
03—Questions
Frequently Asked Questions
What were the primary results of the TETON-1 study?
Nebulized Tyvaso demonstrated superiority over placebo for the change in absolute FVC from baseline to week 52, with a 130.1 mL improvement (Hodges-Lehmann estimate, 95% CI 82.2 to 178.1 mL; p<0.0001). The study was a 598-patient, randomized, double-blind, placebo-controlled phase 3 trial conducted in the United States and Canada.
What is the regulatory plan for IPF?
United Therapeutics plans to submit a supplemental New Drug Application to the FDA by the end of summer 2026, seeking priority review to add IPF to the labeled indications for nebulized Tyvaso, based on data from TETON-1 and TETON-2.
How did the overall survival data compare?
Overall survival at week 52 trended in favor of Tyvaso but did not meet statistical significance, according to the press release furnished with this filing.
What safety information was reported?
Treatment with nebulized Tyvaso was well-tolerated, with a safety profile consistent with previous Tyvaso studies and known prostacyclin-related adverse events. No new safety signals were observed.
What other studies are ongoing or upcoming?
TETON-PPF, evaluating nebulized Tyvaso in progressive pulmonary fibrosis, is enrolling globally. Additional TETON-1 results and integrated TETON-1 and TETON-2 analyses are scheduled for presentation at the American Thoracic Society Annual Meeting in Orlando in May 2026.
04—Continue