The Efficacy and Safety of Long-term Pirfenidone Therapy in Patients with Idiopathic Pulmonary Fibrosis

OBJECTIVE: Pirfenidone (PFD) is often used for years, but the efficacy and safety of long-term PFD therapy in patients with idiopathic pulmonary fibrosis (IPF) are not fully understood. METHODS AND PATIENTS: We retrospectively evaluated 46 patients with IPF who received PFD between February 2009 and August 2014. The efficacy and safety of PFD therapy were compared between 2 groups: long-term therapy patients who received PFD for over 1 year (group L, n=30, 65%) and short-term therapy patients who could not receive PFD for more than 1 year due to worsening of their condition or side effects (group S, n=16, 35%). RESULTS: The median age of the 46 patients was 70.5 years, and the median baseline % predicted forced vital capacity (%FVC) was 70.0%. The changes in the FVC in group L were -120 mL and -170 mL at 12 and 24 months after receiving PFD, respectively. The respective median survival times after PFD therapy in groups L and S were 1,612 days and 285 days (p<0.001). The patients in group L experienced a longer time free of acute exacerbation of IPF than those in group S (947 days vs. 145 days, p=0.001). A multivariate analysis revealed that %FVC <60% was a predictor of the inability to receive PFD for over 1 year (odds ratio 0.240, 95% confidence interval 0.060-0.958; p=0.043). With regard to grade 3-5 adverse events, only one patient exhibited grade 3 hyponatremia. CONCLUSION: Long-term PFD therapy is effective, with few severe adverse events.