Long-term treatment strategy for Crohn's disease anal fistula

Objective: To identify better treatment strategies for Crohn's disease anal fistula (aCD), we considered surgical treatment and targeted drug therapy as a series of treatments and examined long-term outcomes.
Method: Data from 45 patients with aCD undergoing surgery and targeted drug therapy (either infliximab (IFX), adalimumab (ADA), or ustekinumab (UST)) at our hospital and related hospitals between 2009 and 2019 was retrospectively reviewed.
Results: The median follow-up period was 57 months. Surgical procedures consisted of 55 seton drainage, 11 fistulotomy, and 1 fistulectomy. The targeted drugs were IFX, ADA, and UST in 50, 9, and 5 line, respectively. All first-line drugs were anti-TNF drugs. Two cases in which surgery was fistulotomy alone were in remission. Response and remission rates for anti-TNF drugs were 91.1% and 44.4% at first-line and decreased to 64.3% and 14.3% after second-line (p=0.015 and p=0.057, respectively). Response and remission rates for UST after second-line (100% and 60.0%) tended to be higher than for anti-TNF (p=0.12 and p=0.046), but there was no difference when compared to the increased dose of anti-TNF (83.3% and 33.3%).
Conclusion: First-line treatment with surgical drainage and anti-TNF agents has a high response rate, but remission cases are limited. After second-line therapy, increasing the dose of anti-TNF agents or switching to other targeted agents, especially UST, is recommended.