HS: Extended povorcitinib treatment yields progressive responses through 54 weeks

Week 54 data from the STOP-HS trial demonstrate sustained and increasing response rates with povorcitinib therapy. Improvements were observed across Hidradenitis Suppurativa Clinical Response (HiSCR), symptom burden, and quality-of-life measures.

In the pivotal STOP-HS1 (NCT05620823) and STOP-HS2 (NCT05620836) trials, the Janus Kinase 1 (JAK1) inhibitor povorcitinib met the primary endpoint of HiSCR50 at week 12 in patients with hidradenitis suppurativa (HS). Given the chronic, relapsing nature of HS, long-term efficacy is a key consideration. Data up to week 54, presented by Dr Martina Porter (Beth Israel Deaconess Medical Center, MA, USA), provided further insight into sustained treatment effects [1].

The 2 studies enrolled 1,227 adult patients with Hurley stage 2 or 3 disease, corresponding to moderate-to-severe HS. Following the 12-week placebo-controlled phase, patients initially assigned to placebo switched to povorcitinib (75 mg or 45 mg once daily), while those already receiving povorcitinib continued their assigned dose during a 42-week extension period.

At baseline, the mean age was 37 years, 62.8% of participants were female, and 35.1% had Hurley stage 3 disease. Patient-reported outcomes included a mean Dermatology Life Quality Index (DLQI) score of 12.9 and a skin pain numerical rating scale (NRS) score of 5.0.

Long-term results showed continued increases in the proportion of patients achieving HiSCR50 through week 54. At week 12, HiSCR50 rates in STOP-HS1 were 40.6% (75 mg), 40.2% (45 mg), and 29.7% (placebo), and in STOP-HS2 were 42.3%, 42.3% and 28.6%, respectively. By week 54, these rates had increased to 61.9% (75 mg) and 60.2% (45 mg) among patients who continued povorcitinib in STOP-HS1, and to 68.1% and 68.3% among those who switched from placebo. Corresponding results in STOP-HS2 were 57.3% and 64.3% for continuous treatment, and 71.4% and 67.5% for those switching from placebo.

Depending on the dose and study group, higher response thresholds were also observed, with HiSCR90 rates ranging from 23.2% to 36.2% and HiSCR100 rates ranging from 17.9% to 29%. Reductions in abscesses, draining tunnels, and inflammatory nodules were sustained through week 54, with 16.1%–20.2% of patients achieving complete clearance of these lesion types.

Patient-reported outcomes showed clinically meaningful improvements, including a ≥3-point reduction in skin pain NRS (40.5%–46.8%) and a ≥4-point decrease in DLQI (59.4%–64.7%).

According to Dr Porter, both doses of povorcitinib were generally well-tolerated through 54 weeks of treatment, with safety data available for over 1,000 treated patients. The most common adverse events were acne, nasopharyngitis, and upper respiratory tract infections. Serious treatment-emergent adverse events (TEAEs) occurred in 3.7%–6.4% of patients. There was 1 fatal TEAE, 1 case of major adverse cardiovascular event, 8 thromboembolic events, and 23 cases of herpes zoster; no malignancies were reported.

Porter ML, et al. Povorcitinib in patients with moderate to severe hidradenitis suppurativa: 54-week efficacy and safety results from the STOP-HS1 & STOP-HS2 phase 3 studies. S034 Late-Breaking Research: Session 2. AAD 2026, 27–31 March, Denver, CO, USA.