Safety and tolerability of combination therapy with pirfenidone and nintedanib for idiopathic pulmonary fibrosis: A multicenter retrospective observational study in Japan

Background: Phase IV clinical trials in Western countries have reported that combined therapy with pirfenidone and nintedanib for idiopathic pulmonary fibrosis (IPF) has a manageable safety profile. However, data on the long-term safety and tolerability of this combination treatment in the real-world setting in Japan are limited. Methods: The retrospective data of 46 patients with IPF who received combination therapy with pirfenidone and nintedanib were obtained from 16 institutes in Japan. Adverse events and adverse drug reactions (ADRs) were reported through a retrospective review of medical records. Results: Nintedanib and pirfenidone were added to preceding treatment with antifibrotic drugs in 32 (69.6%) and 13 (28.3%) patients, respectively. In one patient (2.1%), the two drugs were concurrently initiated. The mean duration of monotherapy before initiating the combination was 26.3 months. In 26 of 38 patients (68.4%), the Gender-Age-Physiology index stage was II or III. Thirty-three patients (71.7%) had some ADRs, and 14 patients (30.4%) permanently discontinued either drug or both drugs owing to the development of ADRs during the observation period (mean: 59 weeks). The percentage of grade III or IV IPF according to the Japanese Respiratory Society severity classification was higher in patients who permanently discontinued either drug or both drugs than in those who continued both drugs (90.9% [10/11; 3 undetermined grade] vs. 61.1% [11/18; 1 undetermined grade]). Decreased appetite (18/46, 39.1%) and diarrhea (16/46, 34.8%) were frequently observed ADRs. Two patients (4.3%) had serious ADRs (liver toxicity and pneumothorax). Conclusions: Real-world data imply that combination therapy with pirfenidone and nintedanib for IPF has a manageable safety/tolerability profile. (C) 2021 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.