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

July 2025 in “ Allergy ”

Xi Li, Elena Peeva, Yuji Yamaguchi, Zhan Ye, Alexandre Lejeune, Craig Hyde, Emma Guttman‐Yassky

ritlecitinib JAK3/TEC family kinase inhibitor alopecia areata Type I immunity Type II immunity hair keratin genes alopecia totalis alopecia universalis gene expression profiles immune response hair regrowth inflammation JAK inhibitor AA AT AU

Studysummary In this study, ritlecitinib treatment for 12 and 24 weeks downregulated immunity-related genes and upregulated hair keratin genes in patients with alopecia areata, correlating with scalp hair regrowth response. Our plain-language summary of this paper — not a Tressless recommendation.

This study analyzed the effects of ritlecitinib, a JAK3/TEC family kinase inhibitor, on alopecia areata (AA) subtypes in a phase 2a trial with 142 participants. Ritlecitinib treatment over 12 and 24 weeks downregulated Type I and II immunity-related genes and upregulated hair keratin genes, with a stronger effect in patchy-type AA (AAP) compared to alopecia totalis/universalis (AT/AU). Changes in gene and serum protein levels correlated with clinical hair regrowth, suggesting that early molecular responses could predict clinical outcomes. The study supports ritlecitinib's role in modulating immune response and promoting hair regrowth, particularly in AAP, and highlights the potential of baseline gene expression profiles to predict therapeutic responses. Despite limitations, the findings indicate that ritlecitinib effectively targets key immune and hair structural genes, reducing inflammation and promoting hair regrowth in AA patients.

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