Tulisokibart hidradenitis suppurativa results are positive: Merck said on September 30, 2026 that its investigational anti-TL1A antibody met the primary endpoint of a Phase 2b trial in adults with moderate-to-severe hidradenitis suppurativa (HS), a chronic skin disease that causes painful lumps, abscesses and scarring, Reuters reported. The data were presented in a late-breaking session at the 2026 EADV Congress in Vienna.
At week 16, 72% of patients on the high dose and 64% on the medium dose reached HiSCR50, versus 35% on placebo, according to Merck’s announcement. Merck calls the results the first positive Phase 2 data for an anti-TL1A antibody in dermatology.
Key Takeaways: Tulisokibart Hidradenitis Suppurativa
- Merck’s Phase 2b trial met its HiSCR50 primary endpoint at week 16 on both the high-dose and medium-dose regimens.
- HiSCR50 response was 72% on the high dose and 64% on the medium dose, compared with 35% on placebo.
- Merck headlines the study as meeting its primary and key secondary endpoints, but characterizes the secondary results as numerical improvements.
- Merck is studying tulisokibart in six indications, with Phase 3 trials under way in ulcerative colitis and Crohn’s disease.
What Is Tulisokibart?
Tulisokibart (MK-7240) is an investigational humanized monoclonal antibody from Merck that targets TL1A, a tumor necrosis factor-like cytokine involved in inflammation. Merck describes it as designed to address immuno-fibrosis, a key driver of HS progression. It is the centerpiece of Merck’s $10.8 billion acquisition of Prometheus Biosciences, according to Endpoints News.
What Is Hidradenitis Suppurativa?
Hidradenitis suppurativa is a chronic inflammatory skin disease that causes painful lumps, abscesses, tunnels under the skin known as draining fistulae, and scarring, most often in skin-fold areas such as the armpits and groin. It affects about 1 in 100 people worldwide, according to Merck. Because the disease is chronic, patients typically need long-term treatment and ongoing monitoring.
Tulisokibart Hidradenitis Suppurativa Trial Results at a Glance
| Arm | Dose | Patients | HiSCR50 at week 16 | HiSCR75 at week 16 |
|---|---|---|---|---|
| High dose | 480 mg every 2 weeks | 42 | 72% | 41% |
| Medium dose | 480 mg every 4 weeks | 42 | 64% | 40% |
| Low dose | 240 mg every 4 weeks | 21 | 52% | 29% |
| Placebo | None | 44 | 35% | 15% |
HiSCR50 means at least a 50% reduction in abscess and inflammatory nodule count, with no increase in abscess or draining fistula count, compared with the start of treatment. HiSCR75 applies the same test at a 75% reduction.
Merck reported mean improvements on the Dermatology Life Quality Index (DLQI) of 5.62 points on the high dose and 3.50 points on the medium dose, against 2.46 points on placebo, while the low dose showed no DLQI benefit over placebo, according to HCPLive.
How the Phase 2b Trial Was Designed
The study, MK-7240-012, is a multicenter, randomized, double-blind, placebo-controlled Phase 2b trial. Participants received a high, medium or low tulisokibart regimen or placebo during a 16-week double-blind period, followed by a 100-week long-term extension, according to ClinicalTrials.gov. For the primary endpoint, the Bayesian design supplemented concurrent placebo data with historical placebo controls.
Lead investigator Alexa Kimball of Harvard Medical School, who HCPLive notes is a paid Merck consultant, said many patients with HS still do not achieve long-term disease control despite available advanced therapies. In data summarized by GuruFocus, serious adverse events occurred in 2.4% of patients on both the high and medium doses, and no serious infections were reported.
Why the Tulisokibart Hidradenitis Suppurativa Results Matter
The pain, drainage and scarring of HS can take a heavy physical and emotional toll, and a new mechanism that works in this setting would widen the options for patients who do not respond well to current treatments.
In our assessment, the results are encouraging but early. The arms enrolled between 21 and 44 patients, the placebo group still saw a 35% response, and the primary analysis borrowed historical placebo data. Larger Phase 3 trials will need to confirm the size of the effect, how long it lasts and the safety profile, including across the 100-week extension that is part of the current study.
The wider tulisokibart program has had mixed news this year. In its quarterly filing, Merck said the Phase 3 ATLAS-UC induction study in ulcerative colitis met its primary endpoint of clinical remission, while a Phase 2 study in systemic sclerosis-associated interstitial lung disease missed its primary endpoint and will be discontinued, as shown in its 10-Q filing.
What Comes Next After the Tulisokibart Hidradenitis Suppurativa Data
Merck says the Phase 2b results will inform further development of tulisokibart, though the material reviewed for this report does not give a Phase 3 start date for HS. The current study continues into its long-term extension and is estimated to finish in June 2028, according to ClinicalTrials.gov, so longer-term safety and durability data will come later. Investors and clinicians will also watch the Phase 3 ulcerative colitis and Crohn’s disease readouts, which will show how the antibody performs in larger studies.
For related coverage, read our reports on Roche’s fenebrutinib NDA priority review, the acne drugs market and the pruritus therapeutics market, or browse our pharmaceuticals news section.
Frequently Asked Questions About Tulisokibart in Hidradenitis Suppurativa
What is tulisokibart?
Tulisokibart is Merck’s investigational anti-TL1A monoclonal antibody. It is being tested in six indications, including Phase 3 studies in ulcerative colitis and Crohn’s disease, and is not approved anywhere.
What did the Phase 2b trial show?
At week 16, 72% of patients on the high dose and 64% on the medium dose achieved HiSCR50, compared with 35% on placebo. The low dose reached 52%.
What is hidradenitis suppurativa?
Hidradenitis suppurativa is a chronic inflammatory skin disease that causes painful lumps, abscesses and scarring. It affects about 1 in 100 people worldwide, according to Merck.
Is tulisokibart approved for hidradenitis suppurativa?
No. It remains investigational. Larger Phase 3 trials would be needed before any regulatory filing for HS.
This report is based on Reuters coverage, Merck’s announcement and trade-press reports, and was last updated on October 1, 2026. It is for information only and is not medical or investment advice.
