Long-term Inhaled Treprostinil for Pulmonary Hypertension Due to Interstitial Lung Disease: INCREASE Open-label Extension Study

Introduction: The 16-week randomised, placebo-controlled INCREASE trial (RCT) met its primary end-point by improving 6-min walk distance (6MWD) in patients receiving inhaled treprostinil for pulmonary hypertension due to interstitial lung disease (PH-ILD). The open-label extension (OLE) evaluated long-term effects of inhaled treprostinil in PH-ILD.

Methods: Of 258 eligible patients, 242 enrolled in the INCREASE OLE and received inhaled treprostinil. Assessments included 6MWD, pulmonary function testing, N-terminal pro-brain natriuretic peptide (NT-proBNP), quality of life and adverse events. Hospitalisations, exacerbations of underlying lung disease and death were recorded.

Results: At INCREASE OLE baseline, patients had a median age of 70 years and a mean 6MWD of 274.2 m; 52.1% were male. For the overall population, the mean 6MWD at week 52 was 279.1 m and the mean change from INCREASE RCT baseline was 3.5 m (22.1 m for the prior inhaled treprostinil arm and -19.5 m for the prior placebo arm); the median NT-proBNP decreased from 389 pg·mL at RCT baseline to 359 pg·mL at week 64; and the absolute (% predicted) mean forced vital capacity change from RCT baseline to week 64 was 51 mL (2.8%). Patients who received inhaled treprostinil placebo in the RCT had a 31% lower relative risk of exacerbation of underlying lung disease in the OLE (hazard ratio 0.69 (95% CI 0.49-0.97); p=0.03). Adverse events leading to drug discontinuation occurred in 54 (22.3%) patients.

Conclusions: These results support the long-term safety and efficacy of inhaled treprostinil in patients with PH-ILD, and are consistent with the results observed in the INCREASE RCT.