Timing of Initial Hair Regrowth and Clinical Trial-Defined Response Following Ritlecitinib Treatment in Patients With Alopecia Areata

Abstract

Introduction: Ritlecitinib is an oral, selective, dual inhibitor of JAK3 and the TEC family kinases that was approved for treatment of severe alopecia areata (AA) in adults and adolescents aged ≥12 years in June 2023. With the recent approval of ritlecitinib, it is important to understand when patients receiving ritlecitinib can expect therapeutic benefit after initial hair regrowth.

Methods: This post-hoc analysis of an integrated ALLEGRO dataset evaluated the time to clinical trial-defined scalp hair regrowth following initial signs of hair regrowth while receiving ritlecitinib. Among trial participants receiving active ritlecitinib doses (ritlecitinib 50 mg or 30 mg once daily with or without a 4-week 200 mg loading dose), we evaluated the time from initial hair regrowth, defined as Severity of Alopecia Tool change-from-baseline of 30% (SALT₃₀) to the primary clinical trial endpoint of an absolute score of SALT ≤20. We calculated the proportion of patients who achieved SALT₃₀ and SALT ≤20 and evaluated the time between them using Kaplan-Meier-estimated median survival time. Results were analyzed overall and by the time SALT₃₀ was achieved: early (≤24 weeks), middle (25 to ≤48 weeks), and late (>48 weeks).

Results: Among 831 patients included in the analysis, 607 (73%) achieved SALT₃₀, of whom 66% achieved SALT₃₀ before SALT ≤20, 17% achieved both simultaneously, and 17% achieved SALT₃₀, but not SALT ≤20. Most patients achieved SALT₃₀ early (67%), while 19% and 14% achieved middle and late SALT₃₀ response, respectively. Overall, the median time to SALT ≤20 after SALT₃₀ response was 93 days. The median time to SALT ≤20 after SALT₃₀ response was shorter in early SALT₃₀ responders (87 days) compared with middle (170 days) or late (267 days) SALT₃₀ responders.

Conclusions: We observed a substantial amount of time passes from initial hair regrowth until trial-defined clinical response is achieved, even among patients who experienced earlier SALT₃₀ response. These results can help inform treatment expectations and goal setting between patients and their clinicians considering ritlecitinib therapy.