Guselkumab Improves Fistula Remission in Perianal Crohn’s Disease in Phase 3 Trial

Guselkumab demonstrated significant efficacy in achieving fistula remission in patients with perianal fistulizing Crohn’s disease, according to week 24 results from the phase 3 FUZION trial. The findings address a major unmet need in a population with limited effective treatment options.

Perianal fistulizing Crohn’s disease is associated with persistent drainage, recurrent abscesses, and impaired quality of life. Despite combined medical and surgical management, durable healing remains difficult. The randomized, placebo-controlled FUZION study evaluated guselkumab, a dual-acting interleukin-23p19 inhibitor, in adults with active draining perianal fistulas confirmed by MRI.

A total of 286 patients were randomized to receive guselkumab with either every-8-week or every-4-week maintenance dosing, or placebo. The primary endpoint was combined fistula remission at week 24, defined by complete closure of external openings and absence of significant collections on imaging.

At week 24, guselkumab significantly improved remission rates compared with placebo. Combined fistula remission was achieved in 28.3% of patients receiving guselkumab every 8 weeks and 27.0% receiving every-4-week dosing, compared with 10.3% in the placebo group. Treatment completion was high, with more than 90% of participants completing 24 weeks.

The authors reported that “guselkumab demonstrated significantly higher rates of combined fistula remission at week 24 vs placebo,” and concluded that guselkumab “is an efficacious treatment of perianal fistulizing Crohn’s disease…with no new safety signals.” They also noted that FUZION is “the first and only randomized, controlled trial to show efficacy of an IL-23p19 antagonist in perianal fistulizing Crohn’s disease.”

The safety profile was consistent with prior Crohn’s disease studies, with no new concerns identified.

Reference
Peyrin-Biroulet L, Jairath V, Hart A, et al. Guselkumab for perianal fistulizing Crohn’s disease: week 24 results from the phase 3, randomized, double-blind, placebo-controlled, multicenter FUZION study. Presented at: Digestive Disease Week; May 2–5, 2026; Chicago, Illinois.