Use of endoscopic ultrasound to guide adalimumab treatment in perianal Crohn's disease results in faster fistula healing

Background: Perianal disease is a manifestation of Crohn's disease (CD) that has poor long-term treatment outcomes. The aim was to determine if rectal endoscopic ultrasound (EUS)-guided therapy with adalimumab (ADA) can improve outcomes for patients with perianal fistulizing CD. Methods: This is a randomized prospective study comparing serial EUS guidance of fistula treatment versus standard of care in fistulizing perianal CD. At enrollment, all patients underwent a rectal EUS and an EUA with seton placement and/or I&D. Treatment was maximized with immunomodulators, antibiotics, and ADA induction. Surgical interventions were determined by the surgeon's discretion in the control group and assisted by every 12th week EUS in the intervention group. Primary and secondary endpoints where complete drainage cessation at week 48 was fistula status per EUS, respectively. Results: Twenty patients were enrolled: 11 control and 9 EUS guidance. At 24 weeks, 7/9 (78%) in EUS group and 3/11 (27%) in control group had drainage cessation (P 0.04). This significant difference was lost at week 48 (P 0.44). Three patients in the EUS and 1 in the control group had additional surgical intervention. Those in the EUS group had more rapid escalation of ADA dosing (P 0.003). There was no difference in the change in PDAI at week 48 versus baseline (P 0.81). Conclusions: Rectal EUS-guided ADA therapy for CD perianal fistulas showed an initial benefit at 24 weeks, which was lost at week 48. This is likely due to small sample size and higher fistula closure in the controls. However, the faster rate of fistula resolution is a clinically significant finding.