Objective: The goals of this study were to assess the efficacy and tolerability of pirfenidone in patients with idiopathic pulmonary fibrosis (IPF) and to identify predictors of tolerability to pirfenidone.
Methods: We conducted a retrospective observational study. When the patient showed deterioration in the percent forced vital capacity (%FVC) or experienced acute exacerbations or severe adverse events, treatment of the patient with pirfenidone was discontinued. We classified the patients who did not display progression following six months of pirfenidone treatment as the tolerant group and the patients who did display progression as the intolerant group. We retrospectively analyzed differences between the two groups in terms of baseline characteristics. The efficacy of pirfenidone was evaluated by the changes in vital capacity (VC) and %FVC before and after the start of treatment in the tolerant group. Patients A total of 20 patients who had been diagnosed with IPF were treated with pirfenidone.
Results: In the tolerant group, the baseline %FVC (p=0.01) and the percentage diffusing capacity of the lungs for carbon monoxide (DLCO, p=0.02) were significantly higher, and the baseline composite physiologic index (CPI) was significantly lower (p=0.009) than in the intolerant group. In the tolerant group, pirfenidone significantly reduced the decline in VC and %FVC of the patients after treatment. In the intolerant group, five patients discontinued pirfenidone treatment because of anorexia.
Conclusion: We found that pirfenidone was better tolerated in patients with milder disease symptoms, as indicated by their baseline CPI, %FVC and %DLCO, and that patients in the tolerant group could benefit from the use of pirfenidone.