Background and objectiveIdiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive fibrosing interstitial pneumonia. Nintedanib significantly reduced the annual rate of decline in forced vital capacity (FVC) compared with placebo in patients with IPF in two replicate trials (INPULSIS (R)). We examined the efficacy and safety of nintedanib in Japanese patients. MethodsWe conducted pre-specified subgroup analyses of the annual rate of decline in FVC, time to first acute exacerbation (AE), change from baseline in St George's Respiratory Questionnaire (SGRQ) total score and safety using pooled data from the INPULSIS (R) trials for Japanese patients. ResultsIn the overall population, 76 of 638 and 50 of 423 patients in the nintedanib and placebo groups, respectively, were Japanese. Results in Japanese patients were consistent with those in the overall population. In Japanese patients, the adjusted annual rate of decline in FVC was -135.9mL/year in the nintedanib group and -267.7mL/year in the placebo group (difference (95% CI): 131.9 (50.7, 213.1) mL/year); the hazard ratio for the time to first AE was 0.25 (0.06, 1.02); and the adjusted mean change from baseline in SGRQ total score at week 52 was 5.81 in the nintedanib group and 9.68 in the placebo group (difference: -3.87 (-8.51, 0.76)). Diarrhoea and liver-related adverse events were the most common events in the nintedanib group, but were reversible following dose reduction, drug interruption or symptomatic therapy. ConclusionThe present results indicate that the efficacy and safety of nintedanib in Japanese patients are comparable with those in the overall population. This pre-specified subgroup analysis of two Phase III, randomized, placebo-controlled trials (INPULSIS (R)) involving 205 sites in 24 countries including 25 Japanese sites revealed that the efficacy and safety profiles of nintedanib in Japanese patients with idiopathic pulmonary fibrosis were similar to those observed in the overall population of both trials.