A Phase 1, Open-Label Study of the Pharmacokinetics of Ritlecitinib in Children Aged 6–12 Years With Alopecia Areata

This Phase 1 study assessed the pharmacokinetics and safety of ritlecitinib in 15 children aged 6 to <12 years with severe alopecia areata. Over 7 days, participants received 20 mg of ritlecitinib daily, resulting in a median Tmax of 0.5 hours and a mean terminal half-life of 1.19 hours. The geometric mean AUC24 was 437.5 ng∙h/mL, and Cmax was 208.7 ng/mL. The drug was generally well-tolerated, with mild to moderate adverse events in three participants, including one discontinuation due to urticaria. These findings provide initial pharmacokinetic data to guide dosing in pediatric patients and support further studies on ritlecitinib's efficacy and safety in children with alopecia areata.