Comparative Efficacy of Biologic Therapies for Inducing Response and Remission in Fistulizing Crohn’s Disease: Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

The medical treatment of fistulizing Crohn's disease (CD) remains a challenge to clinicians. Over the last 20 years, biologic therapies have been the mainstay of medical treatment of fistulizing CD. The purpose of this study is to compare the efficacy of biologic therapies in inducing response and remission in fistulizing CD.We performed a systematic review of the EMBASE, MEDLINE, and Cochrane Central databases from inception to December 2021. Inclusion criteria were any randomized controlled trials (RCTs) that evaluated the efficacy of biologic therapies against an active comparator or placebo for induction of response or remission in adults with fistulizing CD. The proportion of patients with fistula response or remission, as defined by each clinical trial, was our primary study outcome. A Bayesian random-effects network meta-analysis was used to measure treatment effects and results were reported as odds ratio (OR) and 95% confidence interval (CI).In our analysis, 10 studies were included, and all were RCTs. Infliximab was superior to adalimumab in inducing response (OR, 0.24; 95% CI, 0.06-0.99) but not in inducing remission (OR, 0.31; 95% CI, 0.04-2.27). Tumor necrosis factor antagonists were superior to placebo in the induction of response (OR, 0.51; 95% CI, 0.35-0.750) and remission (OR, 0.36; 95% CI, 0.22-0.58). Infliximab was superior to placebo in inducing response (OR, 0.36; 95% CI, 0.17-0.75) and remission (OR, 0.17; 95% CI, 0.03-0.87). Ustekinumab was superior to placebo in inducing response (OR, 0.48; 95% CI, 0.26-0.860) but not in inducing remission (OR, 0.50; 95% CI, 0.13-1.93). When comparing biologic therapies against each other, there was no statistical difference in inducing remission. Vedolizumab was not superior to placebo in inducing remission (OR, 0.32; 95% CI, 0.04-2.29). Certolizumab was not superior to placebo in inducing response (OR, 0.78; 95% CI, 0.40-1.55) or remission (OR, 0.78; 95% CI, 0.40-1.55).Tumor necrosis factor antagonists are effective in inducing response and remission in fistulizing CD. Infliximab was superior to adalimumab for inducing response but not for inducing remission. Ustekinumab is effective in the induction of response but not in the induction of remission. When compared against each other, biologic therapies showed no significant difference in the induction of remission. Based on the available data, infliximab is the preferred first-line treatment. As for other biologics, the limited published data do not allow us to make firm recommendations. This study supports current practice and emphasizes the need for dedicated RCTs to evaluate the efficacy of biologic therapies in fistulizing CD.Despite the era of biologic therapies, the management of fistulizing Crohn’s disease remains challenging. This is the first systematic review and network meta-analysis to compare the efficacy of biologic therapies in inducing response and remission in patients with fistulizing Crohn’s disease. We found that anti-tumor necrosis factor agents are effective in inducing response and remission. Infliximab was superior to adalimumab for inducing response but not for inducing remission.