Combined results of the TETON-1 and TETON-2 Trials of Inhaled Treprostinil for Idiopathic Pulmonary Fibrosis
In brief
Inhaled treprostinil limited 52-week lung-function loss by 112 mL versus placebo
Across two phase 3 trials involving 1,191 people with idiopathic pulmonary fibrosis, lung function fell by a median 45 mL with inhaled treprostinil versus 162 mL with placebo over 52 weeks. Treprostinil also improved five of six secondary outcomes, including clinical worsening and exacerbations; cough was common, and benefits beyond one year remain unknown.
- Journal
- American journal of respiratory and critical care medicine (Q1)
- Published
- 23 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Steven D Nathan, Peter Smith, Chunqin Deng, Jeffrey Golden, Martine Reynaud-Gaubert, Granthem Farr, et al.
- PMID
- 42776606
- DOI
- 10.1093/ajrccm/aamag507
Why clinicians should know about it
- Picked for Pulmonary and Respiratory Medicine (paper of the day, 24 September 2026): Inhaled treprostinil slows IPF progression
Abstract
BACKGROUND: Inhaled treprostinil has been shown to slow the rate of loss of lung function in IPF patients in two independent studies. A detailed analysis of the fully integrated results of both studies will provide more precise and robust estimates of the drug's efficacy in IPF. METHODS: TETON-1 and TETON-2 were two replicate phase 3 double-blind trials, where patients with IPF were randomized to inhaled treprostinil or placebo. The primary endpoint was change in absolute forced vital capacity (FVC) at week 52. Secondary outcomes were time to clinical worsening, time to IPF exacerbation, survival, percent predicted FVC (ppFVC), quality of life and percent predicted diffusing capacity (ppDLCO) by 52 weeks. RESULTS: There were 1191 patients who underwent randomization and received at least one dose of treprostinil (597 patients) or placebo (594 patients) across both trials. Median change from baseline in FVC was -45.4 ml (95% CI, -73.8 to -23.1) in the treprostinil group and -161.7 ml (95% CI, -194.5 to -134.1) in the placebo group (between-group difference 111.8 ml (95% CI, 79.7 to 144.0, p < 0.0001) at 52 weeks. Treprostinil demonstrated superiority to placebo in five of six secondary efficacy endpoints including: time to first clinical worsening, time to first IPF exacerbation, change from baseline in the K-BILD, ppDLCO, and ppFVC. There were 41 (6.9%) deaths in the inhaled treprostinil group versus 56 (9.4%) deaths in the placebo group. Cough was the most common adverse event. CONCLUSIONS: Inhaled treprostinil slowed the rate of lung function loss, delayed clinical worsening and IPF exacerbations, and demonstrated benefits in DLCO and quality of life over 52 weeks. The results support the use of inhaled treprostinil in patients with IPF.(Funded by United Therapeutics Corp; ClinicalTrials.gov number, NCT04708782 for TETON-1 and NCT05255991 for TETON-2).
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.