Effectiveness of combined therapy with pirfenidone and inhaledN‐acetylcysteine for advanced idiopathic pulmonary fibrosis: A case–control study

BACKGROUND AND OBJECTIVE: Treatment with pirfenidone may slow the decline in vital capacity and increase progression-free survival (PFS) in idiopathic pulmonary fibrosis (IPF). The effects of combination therapy with inhaled N-acetylcysteine (NAC) and pirfenidone are unclear. We assessed the effects of this combination therapy in patients with advanced IPF. METHODS: Patients with a diagnosis of advanced IPF (Japanese Respiratory Society stage III/IV IPF) and a relative decline in forced vital capacity (FVC) of ≥ 10% within the previous 6 (± 2) months were enrolled. Outcomes were evaluated in a 12-month follow-up pulmonary function test. Treatment was considered ineffective if the decline in FVC was ≥ 10% and effective if the decline was <10%. We compared clinical characteristics, effectiveness and PFS between patients receiving inhaled NAC plus pirfenidone (n = 24) and those receiving pirfenidone alone (control; n = 10). RESULTS: Data from 34 IPF patients (age range, 59-82 years) were analysed. At the 12-month follow-up examination, treatment was deemed effective in 8 of 17 (47%) patients receiving NAC plus pirfenidone and in 2 of 10 (20%) receiving pirfenidone alone. The annual rate of change in FVC was -610 mL in the NAC plus pirfenidone group and -1320 mL in the pirfenidone group (P < 0.01). PFS was longer (304 days) in the NAC plus pirfenidone group than in the pirfenidone group (168 days; P = 0.016). CONCLUSIONS: Combination treatment with inhaled NAC and oral pirfenidone reduced the rate of annual FVC decline and improved PFS in patients with advanced IPF.