Prognostic impact of an early marginal decline in forced vital capacity in idiopathic pulmonary fibrosis patients treated with pirfenidone.

Abstract

Pirfenidone (PFD), an oral antifibrotic drug, is conditionally recommended for the treatment of idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the prognostic factors in IPF patients treated with PFD and clarify the clinical significance of marginal physiological changes after PFD therapy. We retrospectively reviewed 96 consecutive IPF patients treated with PFD. The physiological evaluation was performed at 3-6 months after PFD therapy, and the findings were classified into three groups based on the presence of a 5% change in %forced vital capacity (%FVC): improved, stable, and worsened. The clinical characteristics and prognostic outcomes were compared among groups, and the prognostic factors were evaluated by Cox proportional hazards analysis. Of the 96 patients, 25 (26.0%) showed acute exacerbation (AE) and 40 (41.6%) died during the observation period (median, 17 months). Physiological responses could be evaluated in 80 patients and the findings were as follows: improved, 23%; stable, 36%; and worsened, 41%. Time to the first AE and the survival rate were significantly shorter and lower, respectively, in the worsened group than in the improved/stable group (P=0.002, P<0.001, respectively). The prognostic analysis revealed that low %FVC at baseline (hazard ratio [HR]: 0.973 [0.950-0.996]), use of supplemental oxygen (HR: 2.180 [1.041-4.622]), and a "worsened" status after PFD therapy (HR: 5.253 [2.541-11.400]) were significantly associated with a poor prognosis. An early marginal decline in FVC may be important for survival outcomes in PFD-treated IPF patients.