Tulisokibart in ulcerative colitis: Phase 2 results and sustained efficacy through Week 50

touchIMMUNOLOGY coverage of DDW 2026

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What is the mechanism of action of tulisokibart, and what was the rationale for its investigation in UC?

Tulisokibart is an investigational humanized monoclonal antibody directed to a novel target, tumor necrosis factor (TNF)-like cytokine 1A (TL1A), that is associated with both intestinal inflammation and fibrosis. Tulisokibart is thought to bind both soluble and membrane-bound human TL1A.

Clinical studies suggest that tulisokibart may inhibit inflammatory pathways involved in inflammatory bowel disease (IBD), and help reduce intestinal fibrosis, which may be important in altering disease progression in IBD, including ulcerative colitis (UC).

What were the aims, design, and inclusion criteria of the phase 2 study?

ARTEMIS-UC is a phase 2, double-blind, placebo-controlled study designed to assess the efficacy and safety of induction therapy with tulisokibart in patients with moderately to severely active UC. The study consisted of two cohorts that enrolled 178 patients.

In Cohort 1, patients were enrolled regardless of their likelihood of response and were assigned to receive intravenous tulisokibart (1000 mg on day 1 and 500 mg at Weeks 2, 6, and 10) or placebo. In Cohort 2, only patients with a positive test for likelihood of response were enrolled and underwent randomization.

The primary analysis, performed in Cohort 1, assessed clinical remission at Week 12. In addition, patients with a positive test for likelihood of response from Cohorts 1 and 2 were combined in prespecified analyses to assess the efficacy of tulisokibart in this subpopulation.

What was the efficacy profile of tulisokibart compared with placebo at Week 12?

In Cohort 1, a higher percentage of patients had clinical remission at Week 12 with tulisokibart than with placebo. Among patients from Cohorts 1 and 2 with a positive test for likelihood of response, a higher percentage of patients achieved clinical remission with tulisokibart than with placebo.

How was the efficacy of tulisokibart maintained or improved through Week 50 among Week 12 responders?

We assessed symptomatic relief through changes in stool frequency (SF) and rectal bleeding (RB) subscores, as well as disease clearance, defined as the combination of symptomatic relief and mucosal healing, through 50 weeks.

Among week 12 responders randomized to tulisokibart in two dose groups (100 mg or 250 mg), efficacy was sustained or continued to increase through Week 50 in SF normalization (63.6% and 76.0%, respectively), RB resolution (63.6% and 72.0%), and symptomatic remission (54.5% and 68.0%). The proportion of participants who achieved disease clearance continued to increase from 25% among Week 12 responders (vs 1.5% in the placebo group) through Week 50 in both the tulisokibart 100 mg group (31.8%) and 250 mg group (44.0%).