The TETON-2 trial is a multicenter, randomized, double-blind, phase 3 trial that compared inhaled treprostinil (Tyvaso) with placebo in patients with idiopathic pulmonary fibrosis (IPF) for 52 weeks[2][3]. The primary endpoint was change in absolute forced vital capacity (FVC) from baseline to week 52, where inhaled treprostinil showed a statistically significant improvement over placebo in all patient subgroups[3]. The study was the first to demonstrate that inhaled therapy slows the progression of fibrosis as measured by change in FVC in patients with IPF[3]. The study population reflected the typical IPF patient population, with 75% on antifibrotic therapy[3]. Treatment with inhaled treprostinil resulted in fewer events of clinical deterioration compared to placebo[3]. A post hoc analysis of the INCREASE trial showed an improvement in FVC of 168.5 mL (P=0.0108) in IPF patients at 16 weeks[1]. Treprostinil is approved for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease[1]. The study also evaluated the time to clinical deterioration, the time to the first acute exacerbation of IPF and other parameters such as survival and quality of life[2].