Merck’s tulisokibart met the Phase 2b primary endpoint in hidradenitis suppurativa, with higher HiSCR50 responses than placebo at week 16.
Written By: Siddhi Bhadekar, M. Pharm (QA)
Reviewed By: Pharmacally Editorial Team
Merck & Co., Inc. announced on September 30, 2026, that its investigational anti-TL1A monoclonal antibody tulisokibart met the primary endpoint in the Phase 2b MK-7240-012 study (NCT06956235) in adults with moderate to severe hidradenitis suppurativa (HS).
At week 16, 72% of patients receiving tulisokibart 480 mg every two weeks (Q2W) and 64% receiving 480 mg every four weeks (Q4W) achieved Hidradenitis Suppurativa Clinical Response 50 (HiSCR50), compared with 35% receiving placebo. The 240 mg Q4W group achieved a 52% response. Merck also reported numerical improvements in HiSCR75 and Dermatology Life Quality Index (DLQI), with safety comparable to placebo.
Full results are scheduled for presentation at the European Academy of Dermatology and Venereology (EADV) 2026 Congress in a Late-Breaking News session (Abstract LB-26).
Tulisokibart Remains Investigational
Tulisokibart is a humanized monoclonal antibody targeting tumor necrosis factor-like cytokine 1A (TL1A). It has not been approved for HS by the U.S. Food and Drug Administration or other regulatory authorities.
Merck said the Phase 2b findings will inform further development and that it plans to advance tulisokibart toward Phase 3 development in HS. The company describes the findings as the first positive Phase 2 data for an anti-TL1A monoclonal antibody in dermatology.
Hidradenitis Suppurativa and the Role of TL1A
HS is a chronic inflammatory skin disease characterized by painful nodules and abscesses that can progress to draining tunnels, fibrosis, and scarring. Merck estimates that HS affects approximately 1 in 100 people worldwide and notes that many patients continue to experience inadequate long-term disease control.
Tulisokibart is designed to block TL1A signaling. Merck states that TL1A inhibition may reduce Th1, Th2, and Th17 inflammatory activity and interfere with an immuno-fibrotic loop involving inflammation and fibroblast activation. However, the Phase 2b announcement did not report fibrosis-specific outcomes, so this remains a proposed mechanistic rationale rather than a demonstrated clinical finding.
MK-7240-012 Study Design
MK-7240-012 is a multicenter, randomized, double-blind, placebo-controlled Phase 2b study sponsored by Merck Sharp & Dohme LLC.
Participants received:
- 480 mg Q2W: n=42
- 480 mg Q4W: n=42
- 240 mg Q4W: n=21
- Placebo: n=44
The reported groups comprised 149 participants in total and were evaluated over 16 weeks.
The primary endpoint was the proportion achieving HiSCR50 at week 16, defined as at least a 50% reduction in total abscess and inflammatory nodule count without an increase in abscess or draining tunnel count. Key secondary endpoints were HiSCR75 and change from baseline in DLQI. The study used a Bayesian design incorporating historical placebo data alongside concurrent controls for the primary analysis.
Tulisokibart Shows Higher HiSCR50 Responses at Week 16
Treatment Arm | HiSCR50 Response Rate | Difference vs. Placebo |
Tulisokibart 480 mg Q2W | 72% | +37% |
Tulisokibart 480 mg Q4W | 64% | +29% |
Tulisokibart 240 mg Q4W | 52% | +17% |
Placebo | 35% | — |
The high-dose and medium-dose groups showed 37- and 29-percentage-point differences, respectively, versus placebo. The low-dose group showed a 17-percentage-point numerical difference.
Merck’s topline announcement did not provide confidence intervals or p-values. Because historical placebo data contributed to the Bayesian analysis, the full EADV presentation will provide additional detail on the statistical comparison.
HiSCR75 and Quality-of-Life Results
HiSCR75 was achieved by 41%, 40%, and 29% of participants receiving high-, medium-, and low-dose tulisokibart, respectively, compared with 15% receiving placebo.
DLQI decreased by 5.62 points with high-dose tulisokibart and 3.50 points with the medium-dose regimen, compared with a 2.46-point decrease with placebo. The corresponding improvements over placebo were 3.16 and 1.02 points. The low-dose group did not show an improvement over placebo on DLQI.
These secondary findings were reported as numerical improvements and should therefore be considered supportive pending presentation of the complete dataset.
Safety Profile Comparable to Placebo
Merck reported a safety profile comparable to placebo during the 16-week treatment period.
Adverse events occurred in 42.9%, 47.6%, and 52.4% of participants receiving high-, medium-, and low-dose tulisokibart, respectively, versus 40.9% with placebo.
Serious adverse events occurred in 2.4% of participants in both the high- and medium-dose groups, 4.8% in the low-dose group, and 2.3% with placebo. No serious or opportunistic infections were reported. The announcement did not provide a detailed breakdown of adverse events or treatment discontinuations.
What the Results Mean for Tulisokibart Development
The Phase 2b results provide preliminary evidence of higher clinical response rates with tulisokibart than placebo in moderate to severe HS. Both 480 mg regimens produced higher HiSCR50 responses at week 16, while HiSCR75 and DLQI also showed numerical improvements.
Merck has indicated that the findings will inform Phase 3 development. The company has not yet disclosed which dose or doses will advance or when the Phase 3 program will begin.
Full Data Expected at EADV 2026
The current findings are based on Merck’s topline announcement and are not yet available as a complete peer-reviewed dataset. The EADV presentation is expected to provide additional information on statistical analyses and safety outcomes.
Longer-term follow-up will also be important to determine whether the observed clinical responses are sustained beyond the initial 16-week treatment period.
Reference
Merck’s Tulisokibart Met Primary and Key Secondary Endpoints in Phase 2b Study in Patients with Moderate to Severe Hidradenitis Suppurativa (HS), Merck, 30 September 2026
Study to Evaluate Tulisokibart for Hidradenitis Suppurativa (MK-7240-012), ClinicalTrials.gov ID NCT06956235
About the Writer
Siddhi Rajendra Bhadekar (Linkedin) is an M.Pharm professional with expertise in medical and scientific writing, literature review, publication writing, and evidence synthesis, supported by four peer-reviewed publications.
She brings working knowledge of ICH-GCP, MedDRA, pharmacovigilance, ADR/AE reporting, clinical data management, and regulatory documentation.
With experience across pharmaceutical R&D, Quality Control, and Quality Assurance, she combines scientific research skills with strong attention to accuracy and detail.
Her background in manuscript development, publication planning, and scientific communication enables her to translate complex healthcare information into clear, reliable content.