Systematic Review and Meta-analysis of Pirfenidone, Nintedanib, and Pamrevlumab for the Treatment of Idiopathic Pulmonary Fibrosis

Background: The comparative efficacy of pirfenidone, nintedanib, and pamrevlumab in slowing the rate of forced vital capacity (FVC) decline and mortality in patients with idiopathic pulmonary fibrosis (IPF) is unknown. Objective: To perform a systematic review and meta-analysis (MA) of these drugs for IPF. Methods: We searched CENTRAL, PubMed, EMBASE, ClincalTrials.gov, and the World Health Organization’s registry databases up to March 2020. Phase II/III randomized controlled trials in adults with IPF were eligible. The random-effect model was implemented calculating the effect size and respective 95% CI as Cohen’s d for change from baseline FVC (in percentage predicted and liters) and odds ratio (OR) for 10% reduction in FVC and all-cause mortality (ACM). Results: Six studies were included in the MA. For change from baseline in percentage predicted FVC, the MA indicated that the 3 drugs were more effective than placebo (pirfenidone: d=3.30%, 95% CI=2.15-4.45; nintedanib: d=3.15%, 95% CI=2.35-3.95; pamrevlumab: d=4.30%, 95% CI=0.45-8.15). These results are superimposable to those relating to change from baseline FVC in liters (pirfenidone: d=0.09L, 95% CI=0.04-0.14; nintedanib: d=0.13L, 95% CI=0.10-0.16; pamrevlumab: d=0.20L, 95% CI=0.05-0.35). Each drug had a positive effect on 10% reduction in FVC (pirfenidone: OR=0.57, 95% CI=0.45-0.74; nintedanib: OR=0.66, 95% CI=0.51-0.85; pamrevlumab: OR=0.24, 95% CI=0.08-0.73), but only pirfenidone showed an effect on ACM (OR=0.50; 95% CI=0.31-0.83). Conclusion and Relevance: This MA provided encouraging results on pamrevlumab efficacy in slowing the decline in FVC compared with pirfenidone and nintedanib. Actually, in phase 3, it could become a potential IPF treatment.