This multicentre, randomised, double-blind placebo-controlled trial was designed to address the effectiveness of the antioxidant, N-Acetylcysteine (NAC), alone and in ‘triple’ therapy (prednisolone, azathioprine and NAC) in idiopathic pulmonary fibrosis (IPF).

Patients with IPF and mild to moderate lung function impairment (FVC≥50% and TLCO≥30%) were assigned to receive triple therapy, NAC alone or matched placebo for 60 weeks. Target recruitment was 130 patients per group, however, following a planned interim analysis (mean follow-up 32 weeks) the triple therapy arm (n=77) was halted. Compared with placebo (n=78), increased risks of death (8 vs 1), hospitalisation (23 vs 7), and serious adverse events (24 vs 8) were seen. The placebo and triple therapy groups h...