Inhaled treprostinil slows lung function loss in IPF
Primary endpointChange in absolute forced vital capacity (FVC) at week 52
Median change from baseline in FVC (ml)
Where these numbers come from
“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.”
The publication
In a combined analysis of two phase 3 trials, inhaled treprostinil reduced the decline in forced vital capacity by 111.8 ml compared to placebo over 52 weeks in patients with idiopathic pulmonary fibrosis. The treatment also delayed clinical worsening and IPF exacerbations.
Who the findings apply to
The evidence applies to patients with idiopathic pulmonary fibrosis (IPF) who were enrolled in the TETON-1 and TETON-2 trials.
Why this matters
Idiopathic pulmonary fibrosis is a progressive disease with limited treatment options. This integrated analysis provides more precise estimates of efficacy, showing that inhaled treprostinil not only preserves lung function but also improves quality of life and diffusing capacity, supporting its use in this patient population.
What the study found
The primary endpoint was the change in absolute forced vital capacity (FVC) at week 52.
The 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.
The between-group difference was 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.
What the result does not establish
Cough was the most common adverse event reported in the study.
The study was funded by United Therapeutics Corp, the manufacturer of the drug.
The analysis is based on the integrated results of two independent phase 3 double-blind trials.
Authors’ conclusion
“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).”
Study and sources
Combined results of the TETON-1 and TETON-2 Trials of Inhaled Treprostinil for Idiopathic Pulmonary Fibrosis
Randomised trial · Phase 3 · American journal of respiratory and critical care medicine · 2026-09-23
Sources and limitations
- PubMed record PMID 42776606 (PubMed / NLM · 2026-09-24)
- Trial registry NCT04708782 (ClinicalTrials.gov · 2026-09-24)
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