Povorcitinib, Incyte’s oral Janus kinase (JAK) inhibitor, produced clinically meaningful and statistically significant improvements for adults with active moderate-to-severe hidradenitis suppurativa (HS) through Week 24, according to new results from the Phase 3 STOP-HS clinical trial program that were presented at the European Association of Dermatology and Venereology (EADV) 2025 Congress in Paris, France.
As previously reported, both STOP-HS1 and STOP-HS2 studies met their primary endpoint at each tested dose (45mg and 75mg). A significantly higher proportion of patients treated with povorcitinib once daily (QD) vs. placebo achieved Hidradenitis Suppurativa Clinical Response (HiSCR), a ≥50% reduction from baseline in the total abscess and inflammatory nodule count (AN count) at Week 12, with no increase from baseline in abscess or draining tunnel count. In addition, at Week 12, more patients treated with povorcitinib compared to placebo achieved HiSCR75 (a ≥75% reduction from baseline in the total AN count at Week 12), ≥3-point decrease in the Skin Pain Numeric Rating Scale (NRS) score, and Skin Pain NRS30; additionally, fewer patients experienced a flare by Week 12.
Results
The new Week 24 data show nearly 60% of efficacy-evaluable patients among the povorcitinib 45mg and 75mg treatment groups achieved HiSCR50. The percentage of povorcitinib treated patients achieving HiSCR50 compared to placebo at Week 12 and 24 was:
STOP-HS1:
12-week 45mg: 40.2% vs. 29.7%
24-week 45mg: 52.9%-64.0%
12-week 75mg: 40.6% vs. 29.7%
24-week 75mg: 50.0%-62.7%
STOP-HS2:
12-week 45 mg: 42.3% vs. 28.6%
24-week 45mg: 57.1%-58.0%
12-week 75mg: 42.3% vs. 28.6%
24-week 75mg: 56.3%-58.5%
Additionally, across STOP-HS1 and STOP-HS2, povorcitinib treatment in both dosing groups resulted in continued improvements at Week 24 in endpoints associated with higher thresholds of response: HiSCR75 was achieved by 31.0%-40.3%, HiSCR90 by 13.8%-27.7% and HiSCR100 by 9.2%-21.3% of patients treated with povorcitinib. Those treated with povorcitinib also achieved greater improvements in skin pain, reducing pain by the first visit (Week 3) through Week 24. Further, 62%-70% of povorcitinib-randomized patients achieved skin pain scores of Mild or No Pain at Week 24.
In both studies, participants receiving povorcitinib 45 mg and 75 mg achieved dt100 (a 100% decrease in draining tunnels from baseline, among those with ≥1 draining tunnel at baseline): 34.6% and 41.6% at Week 12 and 39.0% and 50.6% at Week 24, respectively.
Safety Profile
The overall safety profile of povorcitinib is consistent with previous data, and both doses were well-tolerated. Treatment-emergent adverse events (TEAEs) for patients who transitioned from placebo to povorcitinib (at Week 12) were 42.4%-54.3%, and 70.2%-78.7% for patients initially randomized to povorcitinib through Week 24. Serious adverse events, and adverse events of special interest (AESI), were observed in 2.9%-4.8% and 0%-1.4% of patients. No MACE or deaths occurred during this period.
“HS is a complex and often misunderstood condition that can profoundly affect patients’ daily lives,” says Martina Porter, MD, STOP-HS study investigator, Assistant Professor of Dermatology at Harvard Medical School, and Vice Chair for Research and Academics in the Department of Dermatology at Beth Israel Deaconess Medical Center, in Boston, MA, in a news release. “Data from the STOP-HS clinical trial program highlight the potential of povorcitinib to address key signs and symptoms for those living with HS, and it is encouraging to see advancements in potential new, effective treatment options for this patient community.”
These data will support the planned regulatory submissions for povorcitinib in HS in Europe and the United States in 2025 and early 2026, respectively.
