Patterns of Clinical Response in Rollover Adolescent Patients with Alopecia Areata Treated with Ritlecitinib in the Ongoing Long-Term, Open-Label, Phase 3 ALLEGRO-LT Study

INTRODUCTION: Ritlecitinib, a JAK3/TEC family kinase inhibitor, demonstrated efficacy in adolescents with alopecia areata (AA) in the ALLEGRO phase 2b/3 study. The present study evaluated long-term Severity of Alopecia Tool (SALT) score response patterns in adolescents from ALLEGRO-2b/3 who rolled over into the open-label, phase 3 ALLEGRO-LT study. METHODS: This post hoc analysis included adolescents aged 12-17 years with AA and ≥ 50% scalp hair loss who received ritlecitinib 50 mg daily, with or without a 4-week 200-mg loading dose. Individual SALT score trajectories from baseline to month 24 were used to categorize adolescents as early (SALT score ≤ 20 at week 24 and months 12 and 24), middle (SALT ≤ 20 at months 12 and 24), or late responders (SALT ≤ 20 at month 24) or partial responders (maintained 30% improvement), relapsers (achieved but did not maintain 30% improvement), or true non-responders (did not achieve 30% improvement). Baseline disease characteristics were assessed by SALT score ≤ 20 response status. RESULTS: Among 57 adolescents, 42.1% had SALT score ≤ 20 response through month 24 (17.5% early, 17.5% middle, and 7.0% late responders). The remaining 57.9% did not achieve SALT score ≤ 20 response, with 15.8% partial responders, 21.1% relapsers, and 21.1% true non-responders. SALT score ≤ 20 responders had shorter AA episode duration, less frequent alopecia totalis/universalis, and were more frequently female versus non-responders. CONCLUSION: A large proportion of adolescents treated with ritlecitinib had an early, middle, or late SALT score ≤ 20 response pattern during 24 months of treatment. Responders (SALT score ≤ 20) had less extensive scalp hair loss and shorter AA episode duration at baseline, and a higher proportion of responders were female compared with non-responders (SALT score > 20). Infographic available for this article. GOV REGISTRATION: NCT03732807 and NCT04006457.