Oral JAK1 Inhibitor Povorcitinib Shows Promise in HS

Abscesses and nodules improve significantly at 12 and 54 weeks.

Apr. 13, 2026 at 11:21am

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A translucent, ghostly X-ray-style image revealing the internal structure of an inflamed skin pore, conceptually representing the pathology of the chronic inflammatory condition hidradenitis suppurativa.An X-ray-like view of an inflamed skin pore hints at the internal pathology of the chronic inflammatory condition hidradenitis suppurativa, which may soon have a new oral treatment option.Chapel Hill Today

An experimental oral JAK1 inhibitor called povorcitinib showed durable benefit in patients with moderate-to-severe hidradenitis suppurativa (HS) through more than a year of treatment, according to a pair of identical placebo-controlled phase 3 trials. At 54 weeks, up to 71.4% of patients taking povorcitinib achieved at least a 50% reduction from baseline in the total abscess and inflammatory nodule count, and up to 29% reached a 100% decrease in abscess and nodule count with no increase in abscesses or draining tunnels.

Why it matters

HS is a chronic, inflammatory skin condition that can be difficult to treat, with at least half of patients having inadequate responses to currently approved injectable biologic therapies. Povorcitinib, an oral JAK1 inhibitor, represents a potential new oral treatment option for patients with moderate-to-severe HS.

The details

The STOP-HS1 (N = 608) and STOP-HS2 (N = 619) trials enrolled patients with moderate-to-severe HS and randomized them 1:1:1 to povorcitinib 45 mg once daily, povorcitinib 75 mg once daily, or placebo. At 12 weeks, the placebo group switched to one of the two povorcitinib doses, and all participants then continued in an open-label extension for 42 weeks. The primary endpoint was at least a 50% reduction from baseline in the abscess and inflammatory nodule count with no increase in abscesses or draining tunnels (HiSCR50) at week 12. At 54 weeks, the percentages reaching this endpoint ranged from 60.2% to 71.4% across the various cohorts. The proportion of treated patients reaching a 100% decrease in abscess and nodule count (HiSCR100) at 54 weeks ranged from 17.9% to 29.0%.

  • The STOP-HS1 and STOP-HS2 trials enrolled patients from 2023 to 2025.
  • The primary endpoint was measured at 12 weeks, and the open-label extension continued for an additional 42 weeks, for a total study duration of 54 weeks.

The players

Martina L. Porter, MD

Assistant professor and vice chair for research and academics in the Department of Dermatology at Harvard Medical School and Beth Israel Deaconess Medical Center, Boston.

Christopher Sayed, MD

Professor of dermatology at The University of North Carolina at Chapel Hill, who is familiar with the study findings but did not take part in the research.

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What they’re saying

“HS is not a disease that is treatable in 12-16 weeks. In the clinical arena, we are really interested in what happens to patients over a year's time.”

— Martina L. Porter, MD, Assistant professor and vice chair for research and academics in the Department of Dermatology at Harvard Medical School and Beth Israel Deaconess Medical Center, Boston

“While these [injectable biologics] achieve great results in some patients, at least half will have inadequate responses and need to consider other options.”

— Christopher Sayed, MD, Professor of dermatology, The University of North Carolina at Chapel Hill

What’s next

Povorcitinib is set to be the first oral small molecule approved for the treatment of HS, which would provide a new oral treatment option and mechanism of action for patients who have failed or have contraindications to other therapies.

The takeaway

The durable efficacy and manageable safety profile of povorcitinib over 54 weeks of treatment suggest it could be a promising new oral therapy for patients with moderate-to-severe hidradenitis suppurativa, a chronic and debilitating skin condition that has historically been difficult to treat.