Povorcitinib Shows Sustained Efficacy in HS at 24 Weeks

At the 2025 European Academy of Dermatology and Venereology (EADV) Congress, Incyte presented new 24-week interim data from the pivotal phase 3 STOP-HS clinical trial program evaluating povorcitinib (INCB54707), an oral, highly selective JAK1 inhibitor, in adult patients with moderate to severe hidradenitis suppurativa (HS). These findings underscore the potential of povorcitinib as a promising treatment option for this challenging condition.¹

Study Design and Objectives

The STOP-HS program comprises 2 phase 3 studies: STOP-HS1 (NCT05620823) and STOP-HS2 (NCT05620836). Both trials enrolled approximately 600 adult patients with moderate to severe HS, characterized by a total abscess and inflammatory nodule (AN) count of ≥5 and lesions in at least 2 distinct anatomical areas. Eligible participants had a documented history of inadequate response to at least a 3-month course of conventional systemic therapies or had demonstrated intolerance to or contraindication for such treatments. The primary endpoint was the proportion of patients achieving a ≥50% reduction from baseline in the total AN count at week 12 (HiSCR50), with no increase from baseline in abscess or draining tunnel count. Key secondary endpoints included HiSCR75, HiSCR90, HiSCR100, and improvements in skin pain as measured by the Numeric Rating Scale (NRS).

Efficacy Results at Week 24

At week 24, povorcitinib demonstrated sustained efficacy across both dosing groups (45 mg and 75 mg) in both STOP-HS1 and STOP-HS2 trials. Nearly 60% of efficacy-evaluable patients achieved HiSCR50, with response rates ranging from 52.9% to 64.0% for the 45 mg dose and 50.0% to 62.7% for the 75 mg dose. Additionally, 31.0% to 40.3% of patients achieved HiSCR75, 13.8% to 27.7% achieved HiSCR90, and 9.2% to 21.3% achieved HiSCR100. These results indicate that povorcitinib provides clinically meaningful improvements in the signs and symptoms of HS.

Researchers found povorcitinib also led to significant reductions in skin pain. By week 24, 62% to 70% of patients reported mild or no pain, a notable improvement from baseline. These findings suggest that povorcitinib not only addresses the inflammatory lesions characteristic of HS but also alleviates the associated pain, thereby enhancing patients' quality of life.

Draining Tunnel Response

In patients with draining tunnels at baseline, povorcitinib treatment resulted in a 100% decrease in draining tunnels from baseline in 34.6% to 50.6% of patients by week 24. This outcome highlights the potential of povorcitinib to address one of the more challenging aspects of HS, which often leads to significant morbidity and scarring.

Safety Profile

The safety profile of povorcitinib remained consistent with previous reports. Treatment-emergent adverse events were observed in 42.4% to 54.3% of patients who transitioned from placebo to povorcitinib at week 12, and in 70.2% to 78.7% of patients initially randomized to povorcitinib through week 24. Serious adverse events occurred in 2.9% to 4.8% of patients, and adverse events of special interest were noted in 0% to 1.4% of patients. Notably, no major adverse cardiovascular events or deaths were reported during this period. Researchers stated these findings suggest that povorcitinib is well-tolerated and has a manageable safety profile.

Clinical Implications

The 24-week data from the STOP-HS trials position povorcitinib as a promising oral treatment option for patients with moderate to severe HS. Its ability to deliver rapid and sustained improvements in both inflammatory lesions and pain, coupled with a favorable safety profile, addresses a significant unmet need in the management of the condition.² The oral administration of povorcitinib offers a convenient alternative to injectable therapies, potentially improving patient adherence and overall treatment satisfaction.

Incyte plans to submit regulatory applications for povorcitinib in HS in Europe and the United States in 2025 and early 2026, respectively. Pending regulatory approvals, povorcitinib could become an integral part of the therapeutic armamentarium for HS, providing clinicians with an effective and well-tolerated treatment option for their patients.

References

1. Incyte announces new 24-week phase 3 data from the STOP-HS clinical trial program of povorcitinib in hidradenitis suppurativa at EADV 2025. News release. Incyte. Published September 17, 2025. Accessed September 17, 2025. https://investor.incyte.com/news-releases/news-release-details/incyte-announces-new-24-week-phase-3-data-stop-hs-clinical-trial
2. McCarthy S. Hidradenitis suppurativa. Annu Rev Med. 2025;76(1):69-80. doi:10.1146/annurev-med-051223-031234