Objective To assess the efficacy of pirfenidone in patients with advanced-stage idiopathic pulmonary fibrosis (IPF), we conducted a retrospective study of patients who received pirfenidone therapy. In addition, the combined effects of inhaled N-acetylcysteine (NAC) and pirfenidone were evaluated.
Methods Eligible patients had a clinical and radiologic diagnosis of advanced-stage IPF (stages of severity III&IV). Patients who exhibited a relative decline in forced vital capacity (FVC) of 10% or more within the preceding six (±2) months were enrolled. The outcome was evaluated from the date of the 6-month follow-up PFT. Relative declines in FVC of more than 10% were defined as progressive disease (ineffective group), while those less than 10% were defined as stable disease (effective group). The clinical features were compared between the two groups. We also compared the efficacy of the combined therapy with inhaled NAC and pirfenidone (n=11) with that of pirfenidone alone (n=7).
Results Eighteen patients 59-82 years of age with IPF who received pirfenidone therapy were reviewed. Pirfenidone stabilized declines in FVC by 10% at six months in eight of the 18 cases (44%). The median changes in FVC at six months were +120 mL in the effective group and -590 mL in the ineffective group. The number of NAC users was significantly higher in the effective group (7/8=87.5%) than in the ineffective group (3/10=30%) (p=0.02). Furthermore, the use of combined NAC therapy was correlated with a favorable outcome. The median change in FVC at six months was 0 mL in the NAC group and -290 mL in the non-NAC group. The median survival period was 557±66 days in the NAC group and 196±57 days in the non-NAC group (p=0.03).
Conclusion Among the advanced-stage IPF patients with a more progressive status, pirfenidone decreased the rate of decline in FVC. In addition, patients treated with pirfenidone combined with NAC therapy exhibited favorable outcomes. Additional studies are needed to confirm the efficacy of this combined therapy for IPF.