In Crohn's disease with fistulising perianal disease refractory to antibiotics and azathioprine, which biologic therapy is specifically approved and has the best evidence for fistula closure?

• A Vedolizumab (anti-α4β7 integrin) as first biologic choice
• B Infliximab (anti-TNF-alpha) based on ACCENT II trial ✓
• C Ustekinumab (anti-IL-12/23) as first-line fistula therapy
• D Risankizumab (anti-IL-23 p19) for perianal fistula as first approval

Explanation

Infliximab (anti-TNF-α chimeric antibody) has the strongest evidence and was the first biologic approved for fistulising Crohn's disease. The ACCENT II trial (2002) demonstrated 36% complete fistula closure with infliximab vs 19% placebo at 54 weeks. Induction at 0/2/6 weeks followed by maintenance every 8 weeks is standard. Vedolizumab has gut-selective mechanism but less fistula-specific evidence. Ustekinumab and risankizumab have emerging data but infliximab remains the established first-line biologic for perianal fistula.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.