Superior Efficacy of Infliximab Versus Adalimumab for First-Line Treatment of Crohn’s Perianal Fistulae

Background Crohn’s disease perianal fistulae (CD-PAF) occur in 25% of patients and are notoriously challenging to manage. Tumor necrosis factor inhibitors are first line agents. Aims The aim of this study was to compare infliximab (IFX) versus adalimumab (ADA) efficacy in CD-PAF healing over time. Methods A retrospective study at two large-tertiary medical centers was performed. Inclusion criteria were actively draining CD-PAF and initial treatment with IFX or ADA following CD-PAF diagnosis. The primary endpoints were perianal fistula response and remission at 6 and 12 months. Secondary endpoints included biologic persistence over time and dose escalation at 6 and 12 months. Results Among 151 patients included in the study, 92 received IFX and 59 received ADA as first line agents after CD-PAF diagnosis. At 6 months, the 64.9% of the IFX group and 34.8% of the ADA group demonstrated CD-PAF clinical improvement ( p < 0.01). Univariate and multivariate analyses demonstrated significant differences among the IFX and ADA groups for clinical response at 6-months and 12-months ( p = 0.002 and p = 0.042, respectively). There were no factors that predicted response, with the exception of concomitant immunomodulator affecting the 6-month clinical response ( p = 0.021). Biologic persistence, characterized by Kaplan Meier methods, was significantly longer in the IFX group compared to the ADA group (Log-rank p = 0.01). Conclusion IFX induction and maintenance is associated with higher rates of response and remission in CD-PAF healing as well as higher treatment persistence compared to ADA. Additionally, our study supports the use of concomitant immunomodulator therapy for CD-PAF healing and remission.