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.