Inhaled treprostinil slowed FVC loss by about 110 mL a year in IPF

Design

Pooled analysis of two replicate phase 3, double-blind, placebo-controlled trials

Population

1,191 patients with idiopathic pulmonary fibrosis

Primary outcome

Change in absolute FVC at 52 weeks

Effect

−45 mL vs −162 mL; difference 112 mL (95% CI 80–144)

TETON-1 and TETON-2 were replicate phase 3 double-blind trials of inhaled treprostinil against placebo in idiopathic pulmonary fibrosis. This report pools 1,191 randomised patients for more precise estimates. It was published on 23 September.

At 52 weeks, FVC fell by a median of 45 mL on treprostinil and 162 mL on placebo, a difference of 112 mL (95% CI 80–144). Treprostinil was better on five of six secondary outcomes, including time to clinical worsening, time to first exacerbation, quality of life (K-BILD), DLCO and percent predicted FVC. Deaths were 6.9% against 9.4%, a numerical difference the abstract does not report as a tested outcome. Cough was the commonest adverse event.

The FVC effect is similar in size to that of the existing antifibrotics, and it comes from a drug with a different mechanism, which raises the question of combination. The abstract does not say how many patients were also taking nintedanib or pirfenidone. Inhaled treprostinil's approval status for IPF should be checked locally; in India, cost and availability are likely to limit use.

• Discuss inhaled treprostinil as an emerging option for IPF where it is approved and available.
• Expect cough as the commonest side effect, which can be troublesome in a disease already marked by cough.
• Continue established antifibrotic therapy; this does not replace nintedanib or pirfenidone.
• Monitor FVC and DLCO at each review to judge progression on any treatment.

Why it matters

IPF may gain a third drug class that works by a different route from current antifibrotics.

Don't overread it

The lower death count was not reported as a tested outcome and does not establish a survival benefit.

The statistics, in plain English

A 112 mL difference in FVC over a year is about two thirds less decline than on placebo. The mortality difference is numerical only; with fewer than 100 deaths in total, it should not be read as a survival benefit.

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