Molecular and clinical effects of selective tyrosine kinase 2 inhibition with deucravacitinib in psoriasis

Background: Psoriasis, a chronic inflammatory disease dependent on the IL-23/T(H)17 pathway, is initiated through plasmacytoid dendritic cell activation and type I IFN induction in the skin. Deucravacitinib, a selective tyrosine kinase 2 (TYK2) inhibitor, blocks IL-23, IL-12, and type I IFN signaling in cellular assays. Objective: We investigated changes in IL-23/T(H)17 and type I IFN pathway biomarkers and gene responses as well as measures of selectivity for TYK2 over Janus kinases (JAKs) 1-3 in patients with moderate to severe psoriasis receiving deucravacitinib. Methods: Deucravacitinib was evaluated in a randomized, placebo-controlled, dose-ranging trial. Biopsy samples from nonlesional (day 1) and lesional skin (days 1, 15, and 85) were assessed for changes in IL-23/IL-12 and type I IFN pathway biomarkers by quantitative reverse-transcription polymerase chain reaction, RNA sequencing, and immunohistochemistry. Laboratory markers were measured in blood. Percentage change from baseline in Psoriasis Area and Severity Index (PASI) score was assessed. Results: IL-23 pathway biomarkers in lesional skin returned toward nonlesional levels dose-dependently with deucravacitinib. IFN and IL-12 pathway genes were normalized. Markers of keratinocyte dysregulation, keratin-16, and beta-defensin genes approached nonlesional levels with effective doses. Select laboratory parameters affected by JAK1-3 inhibition were not affected by deucravacitinib. Greater improvements in PASI scores, correlated with biomarker changes, were seen with the highest doses of deucravacitinib versus lower doses or placebo. Conclusion: Robust clinical efficacy with deucravacitinib treatment was associated with decreases in IL-23/TH17 and IFN pathway biomarkers. The lack of effect seen on biomarkers specific to JAK1-3 inhibition supports selectivity of deucravacitinib for TYK2; larger confirmatory studies are needed.

Automated summary

Deucravacitinib treatment shows robust clinical efficacy by decreasing IL-23/TH17 and IFN pathway biomarkers in patients with psoriasis. The lack of effect on biomarkers specific to JAK1-3 inhibition supports the selectivity of Deucravacitinib for TYK2.