Merck & Co., reported that its investigational anti-TL1A monoclonal antibody tulisokibart met the primary endpoint of the Phase IIb MK-7240-012 trial in moderate-to-severe hidradenitis suppurativa (HS), with results presented at the European Academy of Dermatology and Venereology 2026 Congress. Merck described the findings as the first positive Phase II data for an anti-TL1A monoclonal antibody in dermatology, extending a drug class previously focused largely on inflammatory bowel disease into a new immune-mediated disease setting.
The randomized, double-blind, placebo-controlled study evaluated three dose regimens over 16 weeks. HiSCR50 at week 16 — the primary endpoint — was achieved by 72% in the high-dose group (480 mg Q2W, n=42) and 64% in the medium-dose group (480 mg Q4W, n=42), versus 35% on placebo (n=44). The trial used a Bayesian design augmenting concurrent controls with historical placebo data, which limits direct comparison with conventionally controlled trials.
On key secondary endpoints, HiSCR75 was achieved by 41% and 40% of high- and medium-dose patients versus 15% on placebo. Serious adverse events were infrequent at 2.4% in both active groups versus 2.3% with placebo, and no serious or opportunistic infections were observed.
Tulisokibart binds both soluble and membrane-bound TL1A (tumor necrosis factor-like cytokine 1A), downregulating Th1, Th2, and Th17 pathways.