A 32-year-old woman with Crohn's disease involving the terminal ileum (confirmed on ileoscopy and MR enterography) has fistulising perianal disease despite azathioprine. Which biologic agent is considered the most effective for perianal fistulising Crohn's disease?

• A Vedolizumab — gut-selective anti-integrin antibody
• B Ustekinumab — IL-12/23 inhibitor
• C Infliximab (anti-TNF) — the ACCENT II trial demonstrated maintenance of fistula closure ✓
• D Methotrexate injection — proven efficacy for perianal disease

Explanation

Infliximab (anti-TNF monoclonal antibody) has the strongest evidence for fistulising perianal Crohn's disease — the PRESENT trial showed induction and the ACCENT II trial demonstrated maintenance of fistula closure with infliximab 5 mg/kg every 8 weeks. Anti-TNF agents (infliximab, adalimumab) are considered first-line biologics for fistulising disease. Vedolizumab and ustekinumab are approved for luminal CD but have less robust evidence specifically for perianal fistulae. Methotrexate is used for maintenance of luminal remission but lacks evidence for fistulising disease.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.