Merck's Tulisokibart Becomes First Anti-TL1A Biologic to Achieve Phase 3 Clinical Remission in Ulcerative Colitis
Key Insights
Merck (search) announced positive topline results from the Phase 3 ATLAS-UC induction-only study (Study 2) evaluating tulisokibart in patients with moderately to severely active ulcerative colitis (search).
Tulisokibart is the first anti-TL1A (search) monoclonal antibody to demonstrate clinical remission at 12 weeks in a Phase 3 trial, meeting both primary and key secondary endpoints.
The investigational drug targets TL1A (search), a novel target associated with immuno-fibrosis, addressing both intestinal inflammation and fibrosis in inflammatory bowel disease.
Merck (search) (NYSE: MRK), known as MSD outside of the United States and Canada, today announced positive topline results from the Phase 3 ATLAS-UC induction-only study (Study 2) evaluating tulisokibart (MK-7240), an investigational humanized monoclonal antibody targeting tumor necrosis factor-like cytokine 1A (TL1A (search)), in patients with moderately to severely active ulcerative colitis (search) (UC). The study successfully met its primary endpoint of clinical remission according to the Modified Mayo Score (MMS) at week 12, as well as key secondary endpoints. Consistent with previously reported Phase 2 studies, no safety concerns were identified.
Tulisokibart is the first anti-TL1A (search) monoclonal antibody to demonstrate clinical remission at 12 weeks in moderately to severely active UC in a Phase 3 trial, marking a significant milestone for this novel therapeutic class.
A Novel Mechanism Targeting Immuno-Fibrosis
Tulisokibart was designed to help address immuno-fibrosis, a key driver of disease progression in inflammatory bowel disease (IBD) and other immune-mediated inflammatory conditions. The investigational antibody is directed to TL1A (search), a novel target associated with both intestinal inflammation and fibrosis. Tulisokibart is thought to bind both soluble and membrane-bound TL1A, potentially disrupting the process by which inflammation and fibroblast activation drive disease activity and progression.
Immuno-fibrotic diseases are chronic progressive conditions marked by immune dysregulation, inflammation, and fibroblast activation. The complexity of immuno-fibrosis underscores the need for treatment options that address both inflammation and fibrosis, and Merck (search) is advancing research to deepen the understanding of this disease mechanism.
Phase 3 ATLAS-UC Study Design
ATLAS-UC (NCT06052059) is a Phase 3, randomized, double-blind, placebo-controlled program designed to evaluate the efficacy and safety of tulisokibart in adults with moderately to severely active UC. The program consists of two independent studies: Study 1, which includes both induction and maintenance treatment, and Study 2, which includes only induction treatment.
Study 2 investigated whether at least one tulisokibart dose level is superior to placebo in the proportion of participants achieving clinical remission according to the MMS at week 12. Participants were randomized to receive either a high dose IV of tulisokibart, a low dose IV of tulisokibart, or an IV placebo. Key secondary endpoints at week 12 included the percentage of patients who experienced endoscopic improvement, the percentage of patients who achieved clinical response per MMS, and the percentage of patients who demonstrated histologic-endoscopic mucosal improvement.
Expert Commentary
"These positive Phase 3 induction results for tulisokibart are the first for an anti-TL1A (search) biologic. They represent an important step forward for patients with moderately to severely active ulcerative colitis (search) who – despite available treatments – continue to experience symptoms, and do not achieve clinical remission," said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck (search) Research Laboratories. "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."
The Unmet Need in Ulcerative Colitis (search)
Ulcerative colitis (search) is one of the most common types of IBD and is a chronic progressive immuno-fibrotic disease that affects the large intestine and rectum. Recent evidence suggests that UC involves not only the mucosa but also deeper transmural changes with fibrosis in the colorectal wall. Millions of people worldwide live with UC, and symptoms can be unpredictable and may significantly impact quality of life. UC often follows a relapsing and remitting course, with symptoms that may include diarrhea, rectal bleeding, abdominal pain, bowel urgency, and weight loss. Many patients with UC do not achieve adequate disease control despite the availability of currently approved treatments.
Broadest Development Program in the Anti-TL1A (search) Class
Tulisokibart has the broadest development program in the novel anti-TL1A (search) class and is currently being evaluated in seven disease indications. Phase 3 studies include ATLAS-UC in UC and ARES-CD (NCT06430801) in Crohn's disease (search). Phase 2 studies are evaluating tulisokibart in systemic sclerosis-associated interstitial lung disease (search) (SSc-ILD) (NCT05270668), rheumatoid arthritis (search) (RA) (NCT07176390), psoriatic arthritis (search) (PsA) (NCT07486960), radiographic axial spondyloarthritis (search) (r-axSpA) (NCT07133633), and hidradenitis suppurativa (search) (HS) (NCT06956235).
Next Steps
Results from the ATLAS-UC Study 2 will be presented with the results from the ongoing induction and maintenance study (Study 1) at an upcoming scientific congress and will be shared with regulatory authorities. Merck (search)'s broader immunology research is focused on investigating novel targets such as TL1A (search) and CD30L, as well as newer modalities like T-cell engagers, exploring their potential across a range of immune-mediated inflammatory diseases.