Onset of Clinical Response with Deucravacitinib in Patients with Moderate to Severe Scalp Psoriasis: A Post Hoc Analysis of the Phase 3b/4 PSORIATYK SCALP Trial

Introduction: Deucravacitinib, an oral, selective, allosteric tyrosine kinase 2 (TYK2) inhibitor, is approved in the US and other countries for treatment of adults with moderate to severe plaque psoriasis who are candidates for systemic therapy. In the phase 3b/4 PSORIATYK SCALP (NCT05478499) trial, deucravacitinib was superior to placebo at Week 16 in patients with moderate to severe scalp psoriasis, including those with more limited overall psoriasis. Here, we report a post hoc analysis evaluating the onset of clinical response in the overall population and in patient subgroups based on body surface area (BSA) involvement. Methods: Outcomes were scalp-specific Physician Global Assessment score of 0 (clear) or 1 (almost clear) (ss-PGA 0/1), ≥75%/≥90%/100% reduction from baseline in Psoriasis Scalp Severity Index (PSSI 75/90/100), adjusted mean change and adjusted percent change from baseline in PSSI, and mean change and percent change from baseline in scalp surface area involvement. Outcomes were evaluated through Week 16 in all randomized patients (BSA involvement ≥3%), patients with BSA involvement 3%-10%, and patients with BSA involvement >10%. P values were obtained using a stratified Cochran-Mantel-Haenszel test, unstratified chi-squared test, or an analysis of covariance; all P values were nominal. Results: ss-PGA 0/1 response rates were significantly higher for deucravacitinib versus placebo by Week 4 in the overall population (11.7% vs 0.0%, P=0.01; n=103 vs 51); ss-PGA 0/1 response rates were higher for deucravacitinib by Week 4 in the BSA 3%-10% subgroup (11.4% vs 0.0%, P=0.03; n=70 vs 38) and by Week 8 in the BSA >10% subgroup (51.5% vs 0.0%, P=0.001; n=33 vs 13). PSSI 90 response rates were also significantly higher for deucravacitinib by Week 8 (BSA ≥3%: 21.4% vs 2.0%, P=0.0016; BSA 3%-10%: 15.7% vs 2.6%, P=0.0388; BSA >10%: 33.3% vs 0.0%, P=0.0170). Adjusted mean percent change from baseline in PSSI total score was significantly greater with deucravacitinib by Week 4 (BSA ≥3%: −40.2% vs −13.8%, P<0.0001; BSA 3%-10%: −35.3% vs −17.0%, P=0.0087; BSA >10%: −51.8% vs −6.8%, P=0.0004). Similar trends were observed for the other efficacy outcomes. Improvements with deucravacitinib continued for all outcomes through Week 16. Conclusion: In PSORIATYK SCALP, deucravacitinib demonstrated significant improvement in scalp-specific efficacy outcomes as early as Week 4, including in patients with more limited overall psoriasis. Improvements continued through Week 16.