J&J's Tremfya lifts Crohn's fistula remission to 35% at one year in Phase 3 FUZION

Johnson & Johnson reported on 19 October 2026 that guselkumab, sold as Tremfya, held or improved fistula remission over 48 weeks in adults with Crohn's disease and draining perianal fistulas, in the Phase 3 FUZION study. The late-breaking data were presented at UEG Week 2026 ¹.

What the trial found

FUZION is a randomised, double-blind, placebo-controlled, multicentre Phase 3 study. Patients had at least one active draining perianal fistula confirmed by blinded central MRI review, a CD Activity Index below 350, and an inadequate response to oral corticosteroids, thiopurines, methotrexate or up to two classes of advanced therapy. They were randomised 2:2:1 to one of two guselkumab regimens or placebo. Both active arms began with 200 mg intravenous doses at weeks 0, 4 and 8, followed by either 100 mg subcutaneously every 8 weeks or 200 mg subcutaneously every 4 weeks ¹.

The main measure was combined fistula remission, which requires both clinical and imaging evidence: all external openings closed with no drainage, no new fistulas, and no fluid collections on MRI ¹.

In the 100 mg every-8-weeks arm, combined fistula remission rose from 28% at week 24 to 35% at week 48. Results in the 200 mg every-4-weeks arm were described as consistent across the same period, and clinically assessed fistula remission followed a similar pattern. More than 90% of randomised patients, including people who had and had not taken biologics before, stayed on treatment through week 48. J&J said safety through week 48 matched the drug's known profile in Crohn's disease ¹.

The week 48 figures build on the week 24 readout first shown at Digestive Disease Week in May 2026. At that point 28% on 100 mg every 8 weeks and 27% on 200 mg every 4 weeks reached combined fistula remission, against 10% on placebo ¹.

What it means for the market

The result matters most to gastroenterology medical affairs and to companies competing in inflammatory bowel disease. J&J describes guselkumab as the only IL-23 inhibitor to show efficacy in a dedicated randomised, placebo-controlled trial in perianal fistulising Crohn's disease, and study investigator Laurent Peyrin-Biroulet called FUZION "the first of its kind in 20 years" ¹. That gives J&J a dedicated randomised dataset in a hard-to-treat subgroup that rival IL-23 products would need their own trials to match.

The drug is already approved in Europe for adults with moderate to severe Crohn's disease and ulcerative colitis, as well as psoriasis and psoriatic arthritis, so the data bear on how prescribers and payers weigh it for patients with fistulas rather than on a new approval ¹. J&J's head of global immunology, David M. Lee, said the company is studying the drug "across the full spectrum" of moderate to severe Crohn's disease ¹. The release does not say whether J&J will seek a label change on the strength of FUZION.

Caveats

The figures come from the company's own announcement of a conference presentation, not a peer-reviewed paper. The release gives no placebo comparison at week 48 and no confidence intervals or p-values for the one-year results, and it gives the every-4-weeks arm's week 48 rate only as consistent rather than as a number. Peyrin-Biroulet is a paid consultant for J&J ¹.

The full week 48 analysis is abstract LB09 at UEG Week 2026, led by Ailsa Hart and Axel Dignass ¹.