Phase 3 trial results show significant reductions in clinical worsening and acute exacerbations for patients with idiopathic pulmonary fibrosis (IPF).
RT’s Three Key Takeaways:
- Lung Function Preservation: The TETON-1 study found that nebulized treprostinil (Tyvaso) significantly improved absolute forced vital capacity compared to placebo over 52 weeks in patients with idiopathic pulmonary fibrosis.
- Clinical Risk Reduction: Combined data from two phase 3 trials showed the treatment reduced the risk of clinical worsening by 31% and the risk of acute exacerbations by 48%.
- Regulatory Timeline: United Therapeutics intends to seek priority review from the FDA by late summer 2026 to expand the therapy’s indications to include idiopathic pulmonary fibrosis.
Results from the TETON-1 phase 3 study and combined analyses with the TETON-2 study, which evaluated nebulized treprostinil (Tyvaso) for the treatment of IPF, have been published in the New England Journal of Medicine and presented at ATS 2026, according to United Therapeutics.
TETON-1 met its primary efficacy endpoint, showing that treprostinil significantly improved absolute forced vital capacity (FVC) relative to placebo from baseline to week 52. The median change in FVC was -43.3 mL in the treprostinil group compared to -196.2 mL in the placebo group, representing a between-group difference of 130.1 mL.
The study also found a 33% reduction in the risk of clinical worsening events for patients receiving the treatment. Improvements were noted across all subgroups, including smoking status, supplemental oxygen use, and the use of background healthcare therapies such as nintedanib and pirfenidone.
Nebulized treprostinil is currently investigational and has not been approved by the FDA for the treatment of IPF.
“The results of TETON-1 validate what was seen in TETON-2. The combined analysis provides an incredibly powerful dataset with both studies complementing each other well,” said Steven D Nathan, MD, chair of the TETON steering committee, in a news release. “The meaningful effect on FVC decline observed across all subgroups, as well as achieving positive results for five out of six secondary endpoints in the combined analysis, is truly impressive for a 52-week treatment duration.”
Combined analyses of TETON-1 and TETON-2 further demonstrated that treprostinil achieved statistically significant treatment effects for the primary endpoint and most secondary endpoints. The combined data showed a 31% reduction in the risk of clinical worsening and a 48% reduction in the risk of acute IPF exacerbations compared to placebo.
“Nebulized treprostinil combines direct lung delivery with multimodal activity across fibrotic, vascular, and inflammatory pathways that are not currently addressed by existing IPF therapies,” said Peter Smith, PharmD, senior vice president of product development at United Therapeutics.
The company plans to submit a supplemental New Drug Application to the FDA by the end of summer 2026, requesting priority review for the IPF indication. Treprostinil has already received orphan designation for IPF from both the FDA and the European Medicines Agency.
