Merck, known as MSD outside the US and Canada, has announced results from the Phase 2b MK-7240-012 trial evaluating tulisokibart, an investigational monoclonal antibody targeting tumour necrosis factor-like cytokine 1A (TL1A), in patients with moderate to severe Hidradenitis Suppurativa (HS). The data are being presented in a Late-Breaking News session at the European Academy of Dermatology and Venereology (EADV) 2026 Congress.

The trial met its primary endpoint, with both high-dose and medium-dose tulisokibart regimens demonstrating superiority over placebo in achieving Hidradenitis Suppurativa Clinical Response 50 (HiSCR50) at Week 16. HiSCR50 was achieved by 72 percent of patients receiving the high-dose regimen of 480 mg every two weeks and 64 percent receiving 480 mg every four weeks, compared with 35 percent in the placebo group. An exploratory analysis showed a 52 percent response rate with the low-dose 240 mg every four weeks regimen.

For HiSCR75, 41 percent of patients in the high-dose group, 40 percent in the medium-dose group and 29 percent in the low-dose group achieved a response, compared with 15 percent of placebo recipients. Quality-of-life measures also showed numerical improvements in the high- and medium-dose groups, based on changes in the Dermatology Life Quality Index (DLQI).

The safety profile was comparable between tulisokibart and placebo groups. Adverse events were reported in 42.9 percent of participants receiving the high-dose regimen, 47.6 percent in the medium-dose group and 52.4 percent in the low-dose group, compared with 40.9 percent with placebo. Serious adverse events were infrequent, occurring in 2.4 percent, 2.4 percent, 4.8 percent and 2.3 percent of participants in the respective groups. No serious or opportunistic infections were reported.

MK-7240-012 is a randomised, double-blind, placebo-controlled Phase 2b study evaluating the efficacy and safety of tulisokibart in patients with moderate to severe HS. The 16-week study assessed HiSCR50 as the primary endpoint, while HiSCR75 and change in DLQI were among the key secondary endpoints.

The findings are expected to inform the Phase 3 development of tulisokibart in HS. Merck is also evaluating the investigational therapy across multiple immune-mediated inflammatory diseases, including ulcerative colitis, Crohn’s disease, rheumatoid arthritis, psoriatic arthritis and radiographic axial spondyloarthritis.

Hidradenitis suppurativa is a chronic inflammatory skin disease characterised by painful nodules and abscesses that can progress to tunnels, fibrosis and scarring. Tulisokibart is designed to block TL1A signalling and is being investigated as a potential treatment across several immune-mediated inflammatory conditions.