Incyte Reports Positive 54-Week Povorcitinib Results in Hidradenitis Suppurativa at AAD 2026
Incyte has reported encouraging long-term results from its Phase 3 STOP-HS clinical trial program, highlighting the sustained efficacy and safety of povorcitinib in treating hidradenitis suppurativa (HS). The findings, which cover a 54-week treatment period, were presented as late-breaking data at the American Academy of Dermatology (AAD) 2026 Annual Meeting held in Denver.
Strong and Sustained Clinical Efficacy
The Phase 3 STOP-HS program, consisting of two pivotal studies—STOP-HS1 and STOP-HS2—demonstrated that povorcitinib delivers significant and durable clinical benefits for adults with moderate to severe HS. Over the 54-week period, patients treated with the oral JAK1 inhibitor showed consistent improvement across multiple key efficacy endpoints.
A major highlight of the study was the proportion of patients achieving HiSCR50, a standard clinical measure defined as at least a 50% reduction in inflammatory lesions without worsening of abscesses or drainage tunnels. Up to 71.4% of patients reached this benchmark by week 54, indicating a robust and sustained response to treatment.
Even more stringent measures of improvement were also met.Incyte Up to 57% of participants achieved HiSCR75, reflecting a 75% reduction in lesions, while as many as 29% reached HiSCR100, indicating complete or near-complete resolution of disease activity. These results underscore the depth of response that povorcitinib can achieve, particularly in a condition that is often difficult to treat.
Reduction in Inflammatory Lesions
Povorcitinib demonstrated consistent effectiveness across all major types of HS-related inflammatory lesions, including abscesses, inflammatory nodules, and drainage tunnels. These lesions are hallmark features of HS and are associated with pain, scarring, and reduced quality of life.
By week 54, a notable proportion of patients achieved complete resolution of inflammatory lesions, defined as ANdT = 0 (no abscesses, nodules, or drainage tunnels). This was observed in approximately 16.1% to 20.2% of patients across treatment groups.
Quantitatively, the treatment led to substantial reductions in lesion counts:
- Drainage tunnels decreased by up to 62.0% (75 mg dose) and 57.7% (45 mg dose)
- Inflammatory nodules were reduced by up to 63.2% and 57.0%, respectively
- Abscess counts declined by up to 63.7% and 62.9%
These reductions highlight the drug’s ability to target multiple aspects of HS pathology effectively.
Improvements in Patient Quality of Life
Incyte Beyond clinical lesion reduction, povorcitinib also delivered meaningful improvements in patient-reported outcomes, which are critical in a chronic condition like HS. Patients frequently experience significant physical discomfort, emotional distress, and functional limitations.
At week 54, a substantial proportion of patients reported improvements in:
- Skin pain (40.5% to 46.8%)
- Fatigue (49.0% to 58.0%)
- Skin-related quality of life (59.4% to 64.7%)
- HS-specific quality of life measures (33.7% to 40.2%)
These findings suggest that the treatment not only addresses the physical symptoms of HS but also enhances overall well-being and daily functioning.
Study Design and Treatment Continuation
The STOP-HS trials initially evaluated povorcitinib against placebo over a 12-week double-blind period. Both doses tested—45 mg and 75 mg—successfully met the primary endpoint at week 12, demonstrating superiority over placebo in achieving HiSCR50.
Following this Incyte phase, participants entered a 42-week extension period. Patients who were initially on povorcitinib continued their assigned doses, while those on placebo were re-randomized to receive either 45 mg or 75 mg of the drug. This design allowed researchers to assess both the durability of response and the outcomes of patients who switched from placebo to active treatment.
Favorable Safety Profile
The safety profile of povorcitinib over the full 54-week period remained consistent with earlier findings from shorter-term analyses. Both doses were generally well tolerated, with no unexpected safety concerns emerging.
Treatment-related adverse events (TRAEs) were reported in 76.2% to 83.4% of patients, but the majority were mild to moderate in severity. The most common side effects included:
- Acne
- Nasopharyngitis (common cold symptoms)
- Upper respiratory tract infections
Serious TRAEs were relatively uncommon, occurring in 3.7% to 6.4% of patients. Severe (Grade >3) adverse events were reported in 5.4% to 8.0% of cases. Discontinuation due to adverse events was also low, ranging from 6.1% to 9.4%.
Importantly, adverse events of special interest—such as serious infections, herpes zoster, malignancies, and thromboembolic events—were rare, occurring in less than 2.3% of patients. Only one major adverse cardiovascular event was reported, and it was deemed unrelated to the study drug.
Expert Insights
According to Pablo J. Cagnoni, President and Global Head of Research and Development at Incyte, the 54-week results provide compelling evidence for povorcitinib’s potential as a transformative therapy in HS.
He emphasized that the drug demonstrated sustained improvements across key clinical endpoints, along with a manageable safety profile, positioning it as a promising first-line oral treatment option.
Clinical investigator Martina Porter of Harvard Medical School also highlighted the broader impact of the findings. She noted that HS can severely disrupt daily life and that the improvements observed in both clinical outcomes and patient-reported symptoms—such as pain and fatigue—are particularly meaningful.
She also pointed out that povorcitinib’s mechanism of action differs from currently available injectable therapies, offering a new treatment approach that may appeal to patients seeking oral options.
Regulatory Progress
The positive data from the Incyte STOP-HS program have supported regulatory submissions in major markets. Applications are currently under review by the U.S. Food and Drug Administration and the European Medicines Agency.
If approved, povorcitinib could become an important addition to the treatment landscape for HS, addressing an unmet need for effective, convenient, and well-tolerated therapies.
Conclusion
The 54-week data from the STOP-HS clinical trial program reinforce povorcitinib’s potential as a significant advancement in the treatment of moderate to severe hidradenitis suppurativa. With high response rates, durable efficacy, meaningful quality-of-life improvements, and a consistent safety profile, the therapy stands out as a promising candidate for long-term disease management.
As regulatory reviews progress, the dermatology community will be closely watching for potential approvals that could expand treatment options for patients living with this challenging and often debilitating condition.
About STOP-HS
The STOP-HS clinical trial program comprises two Phase 3 studies, STOP-HS1 (NCT05620823) and STOP-HS2 (NCT05620836), which are evaluating the efficacy and safety of povorcitinib (INCB54707) in adult patients with moderate to severe HS. Both studies included a 12-week, double-blind, placebo-controlled treatment period, followed by a 42-week, double-blind extension period. Eligible participants either continued treatment in the STOP-HS LTE study (NCT06212999) or discontinued treatment and entered a 30-day safety follow-up period.
They each recruited approximately 600 patients (aged 18 years or older) diagnosed with moderate to severe HS for at least three months prior to the screening visit and meeting certain criteria: total number of AN ≥ 5, lesions in at least two distinct anatomical areas, and documented history of inadequate response to at least one conventional systemic treatment (oral antibiotic or biologic) of a minimum duration of three months for HS, or intolerance or contraindication to such Incyte conventional systemic treatments.
The primary endpoint of both studies is the proportion of patients achieving HiSCR50, defined as a reduction of at least 50% from baseline in the total number of AN at week 12, with no increase from baseline in the number of abscesses or fistulas. Key secondary endpoints include the proportion of patients achieving at least a 75% reduction in the number of ankylosing nodules without an increase, from baseline, in the number of abscesses or fistulas (HiSCR75) at week 12, the proportion of patients experiencing at least one flare-up during the 12 weeks, the proportion of patients with a > 3 point decrease in the NRS skin pain score at week 12, among those with a baseline score ≥ 3, and the proportion of patients achieving a 30% reduction and a decrease of at least 1 unit from baseline in the NRS skin pain score at week 12, among those with a baseline score ≥ 3. The studies also assess the frequency and severity of adverse events during the study.
About hidradenitis suppurativa
Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by painful nodules and abscesses that can lead to irreversible tissue destruction and scarring. <sup>1,2</sup> Hyperactivity of the JAK/STAT signaling pathway is thought to underlie the inflammation involved in the pathogenesis and progression of HS.<sup> 3 </sup> It is estimated that over 150,000 patients in the United States suffer from moderate to severe HS.<sup> 3 </sup> Given the debilitating nature of this condition, it can have a profoundly negative impact on patients’ quality of life.<sup> 4 </sup>
About povorcitinib
Povorcitinib (INCB54707) is an orally administered, small-molecule, selective JAK1 inhibitor currently being investigated in Phase 3 clinical trials for moderate to severe HS (STOP-HS1, STOP-HS2, STOP-HS LTE), non-segmental vitiligo (STOP-V1, STOP-V2), and prurigo nodularis (PN; STOP-PN1, STOP-PN2), as well as in a Phase 2 trial for moderate to severe asthma. The Non-Discharge Application (NDA) and Marketing Authorization Application (MAA) for povorcitinib as a potential treatment for patients with moderate to severe HS are currently under review by the U.S. Food and Drug Administration and the European Medicines Agency, respectively. The first phase 3 results concerning povorcitinib in vitiligo and PN are expected in mid-2026 and Q4 2026 respectively.
