Multiomics Analysis of the Response to Ritlecitinib in Alopecia Areata Subtypes and Correlation With Efficacy.

BACKGROUND Alopecia areata (AA) is an autoimmune disease characterized by hair loss. This study examined changes in molecular signatures in lesional scalp of patients with AA subtypes (patchy-type AA [AAP] or alopecia totalis/alopecia universalis [AT/AU]) in response to treatment with JAK3/TEC family kinase inhibitor ritlecitinib and evaluated correlations between potential biomarker levels/changes and scalp hair regrowth. METHODS This was a post hoc analysis of a biopsy substudy from a phase 2a trial of ritlecitinib in patients with AA and ≥ 50% scalp hair loss. Transcriptomic expression profiles from scalp samples of patients with AAP or AT/AU were analyzed using microarray. Changes from baseline in transcriptional and serum protein expression were evaluated, as were correlations between both these changes and the baseline profile with clinical response (scalp hair regrowth). RESULTS Following 12 and 24 weeks of treatment, ritlecitinib downregulated key Type I (CCL5, CD8A, and GZMB) and Type II immunity-related genes (CCL13, CCL18, and IL13RA1), downregulated genes related to ritlecitinib's mechanism of action (ITK, JAK3, and BTK), and upregulated hair keratin genes in AAP and AT/AU lesions, with a lesser extent in AT/AU than AAP lesions. Baseline expression levels and changes from baseline to Weeks 12 and/or 24 in levels of genes and serum proteins related to Type I and II immunity, hair structure/function, and ritlecitinib's mechanism of action significantly correlated with clinical response at Weeks 12 and/or 24. CONCLUSION These results provide support that treatment with ritlecitinib improves the gene expression profile in AA lesional scalp and is correlated with subsequent hair regrowth response. TRIAL REGISTRATION NCT02974868.