New prespecified analyses from the Phase 3 FUZION study show consistent combined fistula remission outcomes with TREMFYA (guselkumab) across clinically important subgroups of adults with Crohn’s disease with perianal fistula. The findings are being presented at the American College of Gastroenterology (ACG) 2026 Annual Scientific Meeting, offering fresh insights into managing one of the most complex manifestations of inflammatory bowel disease.
What Changed
Clinical data from the Phase 3 FUZION study (NCT05347095) evaluated adults with Crohn’s disease and perianal fistula, a debilitating manifestation affecting nearly 25% of patients with Crohn’s disease. In the overall study population at Week 24, 28% of patients receiving TREMFYA 100 mg administered subcutaneously every 8 weeks (q8w) and 27% receiving TREMFYA 200 mg administered subcutaneously every 4 weeks (q4w) achieved combined fistula remission. This compares with 10% of patients receiving a placebo.
Furthermore, the newly presented prespecified subgroup analyses demonstrate that these outcomes remained consistent across various clinically important patient populations. Subgroup Week 24 combined fistula remission results versus placebo include:
- Patients with CDAI >=220: 30% for 100 mg SC q8w, 21% for 200 mg SC q4w, versus 0% for placebo.
- Prior biologic exposure: 21% for 100 mg SC q8w and 29% for 200 mg SC q4w, versus 5% for placebo.
- Proctitis at baseline: 26% for 100 mg SC q8w and 27% for 200 mg SC q4w, versus 12% for placebo.
- Without proctitis at baseline: 29% for 100 mg SC q8w and 27% for 200 mg SC q4w, versus 10% for placebo.
According to study investigators, adverse events observed during the analyses were consistent with the known safety profile of TREMFYA in Crohn’s disease.
Context and Background
Perianal fistulas remain one of the most debilitating manifestations of moderate to severe Crohn’s disease, leaving many patients to experience persistent drainage, pain, and long-term complications. FUZION is noted as the first dedicated Phase 3 randomized, placebo-controlled trial in adults managing Crohn’s disease with perianal fistula in more than 20 years.
TREMFYA is developed by Johnson & Johnson and manufactured by Janssen Biotech, Inc. It is described as a dual-acting monoclonal antibody that blocks IL-23 and binds to CD64 based on in vitro studies, and it is the only approved dual-acting monoclonal antibody in inflammatory bowel disease (IBD) with these mechanisms. Additionally, TREMFYA is recognized as the only IL-23 inhibitor to demonstrate efficacy in a dedicated, randomized, placebo-controlled trial in patients with Crohn’s disease with perianal fistula.
Commenting on the clinical developments, researchers and company representatives highlighted the dedication to addressing high areas of unmet need. “Perianal fistula remain one of the most debilitating manifestations of moderate to severe Crohn’s disease and many patients continue to experience persistent drainage, pain and complications,” clinical leaders noted. “These subgroup analyses show that the outcomes observed with TREMFYA were consistent across clinically important patient populations, further strengthening the evidence supporting its use in this difficult to treat patient population.”
Sector Impact and Business Implications
For Johnson & Johnson and its Janssen Biotech unit, the consistent performance of TREMFYA across complex patient subgroups reinforces its positioning within the competitive immunology and gastroenterology treatment landscape. Clinical trials addressing historically stubborn conditions like perianal fistulas carry significant weight for market adoption, particularly as physicians look for therapies capable of delivering results in patients with prior biologic exposure or baseline proctitis.
“Johnson & Johnson has a longstanding commitment to advancing the science of inflammatory bowel disease, including for patients living with some of its most complex manifestations,” the company shared in statements regarding the research program. “FUZION was designed to generate rigorous evidence specifically in Crohn’s disease with perianal fistula, helping us deepen our understanding of how TREMFYA can address an area of unmet need.”
Limitations and Clinical Considerations
Despite the positive efficacy signals across subgroups, several important limitations and uncertainties remain documented by developers and researchers. While in vitro studies show TREMFYA blocks IL-23 and binds to CD64, the clinical significance of TREMFYA binding to CD64 is currently not known. Furthermore, it is not known if TREMFYA can harm an unborn baby or if it passes into breast milk, pointing to necessary caution in specific patient demographics.
What to Watch Next
As the data are presented at the American College of Gastroenterology (ACG) 2026 Annual Scientific Meeting, gastroenterologists and healthcare systems will be monitoring full publication of the FUZION trial datasets and subsequent regulatory or guideline updates. Observers will also track long-term safety data as post-marketing surveillance and extended trial periods continue to evaluate dual-acting IL-23 inhibition in everyday clinical practice.