Incyte Reports Positive 54-Week Late-Breaking Povorcitinib Data in Hidradenitis Suppurativa at AAD 2026
Incyte has reported new long-term findings from its pivotal Phase 3 STOP-HS clinical development program, highlighting the sustained safety and efficacy of povorcitinib (INCB54707), an investigational oral, highly selective Janus kinase 1 (JAK1) inhibitor, in adult patients suffering from moderate to severe hidradenitis suppurativa (HS). The data, reflecting outcomes over a 54-week treatment period, were presented as part of a late-breaking oral session at the American Academy of Dermatology Annual Meeting 2026, held from March 27 to 31, 2026, in Denver.
Long-Term Data Reinforce Therapeutic Potential
The newly disclosed 54-week results build upon previously announced 12-week and 24-week findings from the STOP-HS1 and STOP-HS2 trials, offering a comprehensive view of povorcitinib’s long-term clinical performance. These studies were designed to evaluate the efficacy and safety of two oral dosing regimens—45 mg and 75 mg—in a population of adults aged 18 years and older diagnosed with moderate to severe HS, a chronic, painful, and often debilitating dermatological condition characterized by recurrent inflammatory lesions.
According to Pablo J. Cagnoni, M.D., President and Global Head of Research and Development at Incyte, the extended data provide compelling evidence that povorcitinib may offer durable and clinically meaningful improvements across multiple disease parameters. He emphasized that the consistent efficacy and manageable safety profile observed over more than one year of treatment reinforce the drug’s potential to significantly alter the therapeutic landscape for HS, particularly as a novel oral alternative to currently available injectable biologics.
Study Design and Clinical Endpoints
Both STOP-HS1 and STOP-HS2 trials successfully met their primary endpoints at Week 12, demonstrating statistically significant improvements in the Hidradenitis Suppurativa Clinical Response (HiSCR50) compared to placebo. Incyte HiSCR50 is defined as at least a 50% reduction from baseline in the total count of abscesses and inflammatory nodules (AN count), without a concurrent increase in abscesses or draining tunnels.
Following the initial 12-week double-blind phase, participants entered a 42-week extension period. Patients originally assigned to the active treatment arms (45 mg or 75 mg) continued their respective doses, while those initially receiving placebo were re-randomized in a 1:1 ratio to receive one of the two active doses of povorcitinib. This design allowed for a robust evaluation of both sustained efficacy and the impact of delayed treatment initiation.
Sustained Clinical Responses Through Week 54
At the 54-week mark, the data demonstrated that povorcitinib produced durable and clinically meaningful responses across both studies and dosing groups. Notably, up to 71.4% of patients achieved HiSCR50, indicating a Incyte substantial reduction in inflammatory lesion burden. Furthermore, higher thresholds of clinical response were also observed, with up to 57% of patients reaching HiSCR75 (≥75% reduction in lesion count) and up to 29% achieving complete response as measured by HiSCR100.
These findings underscore the depth and consistency of treatment benefit over time, suggesting that povorcitinib not only initiates rapid improvements but also maintains and enhances those gains with continued therapy.
Broad Reductions in Inflammatory Lesions
A key hallmark of HS is the presence of multiple lesion types, including abscesses, inflammatory nodules, and draining tunnels. Across both STOP-HS trials, povorcitinib demonstrated consistent and meaningful reductions in all three lesion categories.
By Week 54, reductions in draining tunnel counts reached up to 62.0% in the 75 mg group and 57.7% in the 45 mg group. Similarly, inflammatory nodule counts decreased by up to 63.2% and 57.0% in the respective dose groups, while abscess counts were reduced by as much as 63.7% and 62.9%. Importantly, complete clearance of inflammatory lesions—defined as an ANdT count of zero—was achieved in approximately 16.1% to 20.2% of patients.
These results highlight the drug’s ability to comprehensively address the multifaceted pathology of HS, which is often resistant to treatment and associated with significant morbidity.
Improvements in Patient-Reported Outcomes
Beyond objective Incyte clinical measures, povorcitinib also demonstrated meaningful improvements in patient-reported outcomes, an increasingly important component of therapeutic evaluation in chronic diseases. At Week 54, a substantial proportion of patients reported clinically meaningful reductions in skin pain, with response rates ranging from 40.5% to 46.8% across dosing groups.
Fatigue, another common and debilitating symptom of HS, improved in 49.0% to 58.0% of patients. Additionally, quality of life (QoL) measures showed notable gains, with 59.4% to 64.7% of participants reporting improvements in skin condition-related QoL and 33.7% to 40.2% experiencing enhancements in HS-specific QoL.
Martina Porter, M.D., Assistant Professor of Dermatology at Harvard Medical School and Vice Chair for Research and Academics at the Department of Dermatology at Beth Israel Deaconess Medical Center, noted that HS can significantly disrupt daily life, affecting both physical and emotional well-being. She emphasized that the observed improvements in symptoms such as pain and fatigue, alongside reductions in disease activity, reinforce the potential of povorcitinib as a meaningful therapeutic option.
Safety Profile Remains Consistent
The safety profile of povorcitinib over the 54-week treatment period was consistent with earlier analyses conducted at 24 weeks,Incyte with both dosing regimens demonstrating good tolerability. Treatment-emergent adverse events (TEAEs) were reported in 76.2% to 83.4% of patients, with the majority classified as mild to moderate in severity.
The most commonly reported TEAEs included acne, nasopharyngitis, and upper respiratory tract infections. Importantly, the incidence of serious adverse events remained low, ranging from 3.7% to 6.4%, and was comparable across both studies and dosing groups.
Grade 3 or higher TEAEs occurred in 5.4% to 8.0% of patients, while discontinuations due to adverse events were relatively infrequent, affecting between 6.1% and 9.4% of participants.
Adverse events of special interest, such as herpes zoster infections, serious or opportunistic infections, malignancies, and thromboembolic events, were rare, with incidence rates below 2.3%. Only one major adverse cardiovascular event (MACE) was reported, and it was deemed unrelated to the study drug. Overall, the number of cardiovascular and thromboembolic events observed was low and aligned with previously reported rates in the HS patient population.
Regulatory Progress and Future Outlook
The robust dataset generated from the STOP-HS clinical program has supported regulatory submissions in both major markets. A New Drug Application (NDA) has been submitted to the U.S. Food and Drug Administration, while a Marketing Authorization Application (MAA) is currently under review by the European Medicines Agency.
If approved, povorcitinib has the potential to become the first oral JAK1 inhibitor indicated for moderate to severe HS, offering a convenient and effective alternative to injectable therapies. Its mechanism of action—targeting JAK1-mediated Incyte signaling pathways involved in inflammation—represents a differentiated approach that could address unmet needs in this patient population.
Transforming the HS Treatment Landscape
Hidradenitis suppurativa remains a challenging condition to manage, with limited treatment options and a significant burden on patients’ quality of life. The long-term data from the STOP-HS trials position povorcitinib as a promising candidate capable of delivering sustained disease control, symptom relief, and improved quality of life.
As regulatory reviews progress in the United States and Europe, the dermatology community will be closely monitoring the potential approval and subsequent clinical adoption of povorcitinib. Should it receive authorization, Incyte The therapy could mark a significant advancement in the management of HS, providing patients with a novel, oral treatment option that combines efficacy, durability, and tolerability.
In summary, the 54-week results from Incyte’s Phase 3 program not only confirm the initial promise of povorcitinib but also establish a strong foundation for its future role in reshaping the standard of care for patients living with this chronic and often debilitating disease.
About STOP-HS
The STOP-HS clinical trial program includes two Phase 3 studies, STOP-HS1 (NCT05620823) and STOP-HS2 (NCT05620836), evaluating the efficacy and safety of povorcitinib (INCB54707) in adult patients with moderate to severe HS. Both studies include 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 concluded treatment and entered a 30-day safety follow-up period.
The studies have each enrolled approximately 600 patients (age ≥18 years) diagnosed with moderate to severe HS for at least three months prior to the screening visit and who meet certain criteria: total AN count of ≥5, lesions in at least two distinct anatomical areas and a documented history of inadequate response to at least a Incyte three-month course of at least one conventional systemic therapy (oral antibiotic or biologic drug) for HS or a demonstrated intolerance or contraindication to such conventional systemic therapies.
The primary endpoint for both studies is the proportion of patients who achieve HiSCR50, defined as at least a 50% reduction from baseline in the total AN count at Week 12, with no increase from baseline in abscess or draining tunnel count. Key secondary endpoints include the proportion of patients achieving at least 75% reduction in AN count with no increase from baseline in abscess or draining tunnel count (HiSCR75) at Week 12.
The proportion of patients experiencing at least one flare over 12 weeks, the proportion of patients with a >3-point decrease in the Skin Pain NRS score at Week 12, among those with a baseline score of ≥3, and the proportion of patients achieving a 30% reduction and at least 1-unit reduction from baseline in Skin Pain NRS at Week 12, among those with a baseline score of ≥3. The studies also evaluate the frequency and severity of adverse events during the study.
For more information on the STOP-HS studies, please visit: https://clinicaltrials.gov/study/NCT05620823, https://clinicaltrials.gov/study/NCT05620836, and https://clinicaltrials.gov/study/NCT06212999.
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.1,2 Over-activity of the JAK/STAT signaling pathway is believed to drive Incyte inflammation involved in the pathogenesis and progression of HS.3More than 150,000 patients in the U.S. are estimated to have moderate to severe HS.3 Given the debilitating nature of the condition, it can have a profoundly negative effect on patients’ quality of life.4
About Povorcitinib
Povorcitinib (INCB54707) is an oral small-molecule JAK1 selective inhibitor currently being investigated in Phase 3 clinical trials for moderate to severe HS (STOP-HS1, STOP-HS2, STOP- HS LTE), nonsegmental vitiligo (STOP-V1, STOP-V2) and prurigo nodularis (PN; STOP-PN1, STOP-PN2), as well as a Phase 2 trial for moderate to severe asthma. The New Drug Application (NDA) and Marketing Authorization Application (MAA) for povorcitinib as a potential treatment for patients with moderate to severe HS is under review by the U.S. Food and Drug Administration and European Medicines Agency, respectively. Topline Phase 3 data for povorcitinib in vitiligo and PN are anticipated in mid-2026 and Q4 2026, respectively.
About Incyte®
Incyte is redefining what’s possible in biopharmaceutical innovation. Through deep scientific expertise and a relentless focus on patients, we have built an established portfolio of first-in-class medicines and an extensive pipeline of next-generation medicines across our key franchises: Hematology, Oncology and Inflammation and Autoimmunity.
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