- Design
- Pooled analysis of two replicate phase 3 double-blind RCTs
- Population
- 1,191 adults with idiopathic pulmonary fibrosis
- Primary outcome
- Change in absolute FVC at 52 weeks
- Effect
- −45 ml vs −162 ml; difference 112 ml (95% CI 80 to 144)
A combined analysis of two replicate phase 3 double-blind trials, TETON-1 and TETON-2, in the American Journal of Respiratory and Critical Care Medicine (23 September 2026), randomised 1,191 people with idiopathic pulmonary fibrosis to inhaled treprostinil or placebo for 52 weeks.
Median FVC fell by 45 ml with treprostinil against 162 ml with placebo, a difference of 112 ml (95% CI 80 to 144). Treprostinil was superior on five of six secondary endpoints, including time to clinical worsening, time to first exacerbation, quality of life (K-BILD), percent predicted DLCO and FVC. Deaths were 6.9% against 9.4%, not a formal endpoint claim. Cough was the commonest adverse event.
The trials were funded by the manufacturer, and it is not yet clear how treprostinil adds to nintedanib or pirfenidone, or how it compares with them. The survival difference is descriptive.
The replicated result makes inhaled treprostinil a credible additional antifibrotic option. Its regulatory status for IPF in India is not known to us; check before discussing it with patients.
- Continue established antifibrotic therapy; treprostinil's place alongside nintedanib or pirfenidone is not yet defined
- Expect cough as the main adverse effect of inhaled treprostinil
- Measure FVC and DLCO regularly — both were improved relative to placebo
- Do not quote the mortality difference as proven; it was not a primary endpoint
- Check local regulatory approval before offering treprostinil for IPF
Why it matters
Two replicate phase 3 trials make this one of the more robust new signals in a disease with few effective treatments.
Don't overread it
The lower death rate is descriptive, not a tested survival benefit.
The statistics, in plain English
A 112 ml difference in FVC over a year is roughly two-thirds of the decline seen with placebo. The confidence interval (80 to 144 ml) is well clear of zero, and replication across two trials strengthens it.
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