October 6, 2025--RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, announced it has initiated three Phase 2b trials evaluating the safety and efficacy of tulisokibart (MK-7240), an investigational humanized monoclonal antibody targeting tumor necrosis factor (TNF)-like cytokine 1A (TL1A), in patients with three immune-mediated inflammatory diseases:
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MK-7240-12 ( NCT06956235) studying patients with moderate to severe hidradenitis suppurativa(HS)
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MK-7240-013 ( NCT07133633) studying patients with radiographic axial spondyloarthritis(r-axSpA; also known as ankylosing spondylitis)
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MK-7240-014 ( NCT07176390) studying patients with rheumatoid arthritis(RA)
Global recruitment of these trials has begun, targeting enrollment of more than 640 patients across the three studies.
“The expansion of our tulisokibart clinical development program reflects Merck’s ongoing commitment to addressing the burden of immune-mediated inflammatory diseases,” said Dr. Aileen Pangan, vice president and head of immunology, global clinical development, Merck Research Laboratories. “We’re excited to further evaluate the potential of tulisokibart as a treatment for patients across multiple diseases in rheumatology and dermatology.”
With the initiation of these Phase 2b trials, tulisokibart is now being investigated in a total of six diseases. Merck is also currently conducting two Phase 3 studies evaluating the efficacy and safety of tulisokibart in patients with two different types of inflammatory bowel disease (IBD), ATLAS-UC (NCT06052059) in ulcerative colitis (UC) and ARES-CD (NCT06430801) in Crohn’s disease (CD), and a Phase 2 study in systemic sclerosis-associated interstitial lung disease (SSc-ILD) (NCT05270668). For an overview of Merck’s clinical development program in immunology, please click here.
About hidradenitis suppurativa (HS)
Hidradenitis suppurativa is a chronic inflammatory skin condition that affects hair follicles and is characterized by small, painful abscesses under the skin in areas of the body such as the armpits, groin, buttocks and breasts. Hidradenitis suppurativa affects a variable proportion of the population, with prevalence estimates ranging from 0.1% to 0.8%.
About radiographic axial spondyloarthritis (r-axSpA)
Radiographic axSpA (also known as ankylosing spondylitis) is characterized by chronic inflammation and pain involving the spine and the joints that connect the bottom of the spine to the pelvis. As its name suggests, damage associated with r-axSpA is visible on X-rays. Worldwide, it is thought to affect 0.1% to 1% of all people.
About rheumatoid arthritis (RA)
Rheumatoid arthritis is a chronic autoimmune condition characterized by the inflammation of joints, which can lead to pain, swelling and stiffness. Rheumatoid arthritis can also affect other parts of the body, including the skin, eyes, mouth, heart and lungs. Globally, it is estimated that 17.9 million people are affected by RA, which represents a 13.2% increase since 1990.
About tulisokibart
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. Merck is developing tulisokibart for the treatment of immune-mediated inflammatory diseases including ulcerative colitis (UC), Crohn's disease (CD), systemic sclerosis-associated interstitial lung disease (SSc-ILD), hidradenitis suppurativa (HS), radiographic axial spondyloarthritis (r-axSpA), and rheumatoid arthritis (RA).
Merck’s commitment to immunology
Advances in our understanding of human biology have led to the emergence of innovative medicines and new modalities that aim to change approaches to treatment of immune-mediated inflammatory diseases. Our scientists are applying their expertise to the discovery and development of therapies to help people with immune-mediated inflammatory diseases. Our research efforts are focused on investigating novel targets such as TL1A and CD30L and their potential role in many immune-mediated inflammatory diseases.
About Merck
At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities.