01—Abstract
Summary
Summary of the 8-K filed September 2, 2025. Cited figures are marked; the original filing is the authoritative source.
United Therapeutics Corporation filed this Form 8-K on September 2, 2025 under Item 8.01 (Other Events) to announce positive topline results from its Phase 3 TETON-2 study of nebulized Tyvaso (treprostinil) Inhalation Solution in patients with idiopathic pulmonary fibrosis (IPF).
The study met its primary endpoint, showing a superiority over placebo for the change in absolute forced vital capacity (FVC) of 95.6 mL (Hodges-Lehmann estimate, p<0.0001) from baseline to week 52. Benefits were observed across all subgroups, including background therapy, smoking status, and supplemental oxygen use. Statistically significant improvements versus placebo were also seen in most secondary endpoints, including time to first clinical worsening, percent predicted FVC, King's Brief Interstitial Lung Disease (K-BILD) quality of life questionnaire, and diffusion capacity of lungs for carbon monoxide (DLCO).
Time to first acute exacerbation of IPF and overall survival at week 52 trended in favor of Tyvaso without reaching statistical significance. The company stated the safety profile was consistent with prior Tyvaso studies and no new safety signal was seen. The company intends to use data from TETON-2 and the ongoing TETON-1 study to support a supplemental New Drug Application to add IPF to the labeled indications for nebulized Tyvaso.
United Therapeutics plans to meet with the FDA before year-end to discuss ways to potentially expedite review, and TETON-1 data readout is expected in the first half of 2026. Both the FDA and the European Medicines Agency have granted orphan designation for treprostinil for IPF. Additional TETON-2 results will be presented at the European Respiratory Society Congress on September 28, 2025.
02—Key points
Key Highlights
- TETON-2 Phase 3 study (597 patients, 52-week, randomized, double-blind, placebo-controlled) met its primary endpoint of improvement in absolute FVC versus placebo.
- Change in absolute FVC favored Tyvaso by 95.6 mL (Hodges-Lehmann estimate, p<0.0001) from baseline to week 52.
- Benefits were observed across all subgroups, including background therapy (nintedanib, pirfenidone, or none), smoking status, and supplemental oxygen use.
- Statistically significant improvements versus placebo in most secondary endpoints, including time to first clinical worsening, percent predicted FVC, K-BILD quality of life, and DLCO.
- Time to first acute exacerbation of IPF and overall survival at week 52 trended favorably but were not statistically significant.
- Company plans a supplemental NDA to add IPF to nebulized Tyvaso's labeled indications, with an FDA meeting planned before year-end and TETON-1 readout expected in 1H 2026.
- Treprostinil holds orphan designation for IPF from both the FDA and the European Medicines Agency; no new safety signal was reported.
03—Questions
Frequently Asked Questions
What did the TETON-2 study measure and what were the primary results?
The study's primary endpoint was the change in absolute FVC from baseline to week 52. Tyvaso showed superiority over placebo of 95.6 mL (Hodges-Lehmann estimate, p<0.0001).
Were all secondary endpoints met?
No. Most secondary endpoints were statistically significant, including time to first clinical worsening, percent predicted FVC, K-BILD, and DLCO. Time to first acute exacerbation of IPF and overall survival at week 52 trended in favor of Tyvaso but were not statistically significant.
What are the next regulatory steps for Tyvaso in IPF?
United Therapeutics intends to use data from TETON-2 and TETON-1 to support a supplemental New Drug Application to add IPF to nebulized Tyvaso's labeling. It plans to meet with the FDA before the end of the year to discuss ways to potentially expedite review when TETON-1 results are available, expected in the first half of 2026.
How was the safety profile of Tyvaso in this study?
The company stated that Tyvaso was well-tolerated, with a safety profile consistent with previous Tyvaso studies and known prostacyclin-related adverse events, and that no new safety signal was seen.
When will more detailed TETON-2 data be presented?
Additional TETON-2 study results will be presented at the European Respiratory Society Congress in Amsterdam on September 28, 2025.
04—Continue