Pharmacological Therapies for the Management of Fistulizing Crohn’s Disease: A Systematic Review and Meta-Analysis

Fistulas are a debilitating complication of Crohn's disease (CD). We conducted a systematic review to assess the efficacy of medical therapies for fistulising CD.MEDLINE, Embase, and CENTRAL were searched on May 26, 2022, for randomised controlled trials (RCTs) of pharmacologic therapy in adults with fistulising CD. The primary outcome was induction and maintenance of fistula response. Pooled risk ratios (RRs) and 95% confidence intervals (CI) were calculated. GRADE was used to assess certainty of evidence.Thirty-eight RCTs were included. Nineteen trials (50%) exclusively involved perianal fistula. The remaining studies included some participants with non-perianal fistula. Pooled RRs for anti-tumor necrosis factor (TNF) agents were not statistically significant for induction (RR 1.36, 95% CI 0.97-1.91) or maintenance of fistula response (RR 1.48, 95% CI 0.97-2.27). However, in a sensitivity analysis of studies with fistula response as the primary outcome, anti-TNFs were superior to placebo for induction (RR 1.94, 95% CI 1.10-3.41) and maintenance (RR 1.88, 95% CI 1.23-2.88) of fistula response. Oral small molecules (RR 2.56, 95% CI 1.18-5.53) and mesenchymal stem cell (MSC) therapy (RR 1.26, 95% CI 1.01-1.57) were effective for induction of fistula response. Ustekinumab was associated with maintenance of fistula response (RR 1.80, 95% CI1.04-3.11). Vedolizumab was not superior to placebo. The certainty of evidence ranged from very low to moderate.Very low-to-moderate certainty evidence suggests that anti-TNF therapy, oral small molecules, ustekinumab, and MSCs are effective for perianal fistulising CD. Dedicated fistula studies evaluating biologics and small molecules are needed.