Tulisokibart Meets Phase 3 Endpoints in Ulcerative Colitis, First for Anti-TL1A

Tulisokibart (MK-7240) became the first anti-TL1A monoclonal antibody to demonstrate clinical remission at week 12 in a phase 3 trial of patients with moderately to severely active ulcerative colitis (UC), according to topline results from the ATLAS-UC induction-only Study 2 announced by Merck on June 22, 2026.

In addition to meeting its primary endpoint, tulisokibart achieved key secondary endpoints and demonstrated a safety profile consistent with previous phase 2 studies.

“These positive Phase 3 induction results for tulisokibart are the first for an anti-TL1A biologic. They represent an important step forward for patients with moderately to severely active ulcerative colitis who, despite available treatments, continue to experience symptoms and do not achieve clinical remission,” said Eliav Barr, MD, senior vice president, head of global clinical development and chief medical officer of Merck Research Laboratories, in a statement. “These results reinforce the potential of this novel approach designed to help address immuno-fibrosis, a key driver of chronic immune dysregulation and disease progression in ulcerative colitis.”

Tulisokibart is an investigational humanized monoclonal antibody targeting tumor necrosis factor-like cytokine 1A (TL1A), a pathway implicated in both inflammation and fibrosis in inflammatory bowel disease (IBD) and other immune-mediated inflammatory conditions. The therapy is designed to bind both soluble and membrane-bound TL1A with high affinity, preventing its interaction with death receptor 3 (DR3) and interrupting downstream inflammatory signaling.

ATLAS-UC is a phase 3, randomized, double-blind, placebo-controlled program evaluating the efficacy and safety of tulisokibart in adults with moderately to severely active UC. The program includes 2 independent studies: Study 1, which evaluates induction and maintenance treatment, and Study 2, an induction-only trial.

According to Merck, results from Study 2 will be presented alongside data from the ongoing induction and maintenance Study 1 at an upcoming scientific congress and shared with regulatory authorities.

References

1. Merck’s Tulisokibart Met Primary and Key Secondary Endpoints in the Phase 3 ATLAS-UC Induction-only Study in Patients With Moderately to Severely Active Ulcerative Colitis (UC) - Merck.com. Merck.com. Published June 22, 2026. Accessed June 22, 2026. https://www.merck.com/news/mercks-tulisokibart-met-primary-and-key-secondary-endpoints-in-the-phase-3-atlas-uc-induction-only-study-in-patients-with-moderately-to-severely-active-ulcerative-colitis-uc/

2. The Edge of a New Frontier: Anti-TL1A Monoclonal Antibodies for Ulcerative Colitis - American College of Gastroenterology. American College of Gastroenterology. Published December 11, 2024. Accessed June 22, 2026. https://gi.org/journals-publications/ebgi/kochar_dec2024/