Efficacy and safety of the oral JAK3/TEC family kinase inhibitor ritlecitinib over 24 months: integrated analysis of the ALLEGRO phase 2b/3 and long-term phase 3 clinical studies in alopecia areata.

Background: The ALLEGRO phase 2a and 2b/3 studies demonstrated that ritlecitinib is efficacious and well tolerated in adult and adolescent patients with alopecia areata (AA) up to 48 weeks.

Objective: The efficacy of ritlecitinib through Month 24 and safety through data cutoff were assessed in the ALLEGRO phase 2b/3 study and the ongoing long-term, open-label, phase 3 ALLEGRO-LT study.

Methods: Patients aged ≥12 years with AA and ≥50% scalp hair loss from ALLEGRO-2b/3 who rolled over to ALLEGRO-LT after up to 48 weeks were included. Proportions of patients with responses based on clinician-reported Severity of Alopecia Tool (SALT) score of ≤20 and ≤10, eyebrow assessment (EBA) and eyelash assessment (ELA), patient global impression of change (PGI-C) and patient satisfaction with hair growth are reported through Month 24 for patients who received ritlecitinib 50 mg daily with or without a 200-mg 4-week daily loading dose. Observed and imputed data (last observation carried forward [LOCF]) were reported until December 9, 2022. Safety was assessed throughout.

Results: At Month 12, SALT score ≤20 was achieved by 45.1% and 45.9% (observed) and 40.3% and 41.8% (LOCF) of the 191 and 194 patients who received ritlecitinib 50 mg and ritlecitinib 200/50 mg, respectively. At Month 24, proportions increased to 60.8% and 63.1% (observed) and 46.1% and 50.8% (LOCF), respectively. Patients with abnormal EBA or ELA scores at baseline achieved responses at Month 24 (EBA observed: 57.6% [50 mg], 61.0% [200/50 mg]; EBA LOCF: 46.8% [50 mg], 50.9% [200/50 mg]; ELA observed: 51.2% [50 mg], 62.7% [200/50 mg]; ELA LOCF: 43.2% [50 mg], 51.7% [200/50 mg]). PGI-C response was achieved by patients at Month 24 (observed: 70.0% [50 mg], 76.4% [200/50 mg]; LOCF: 56.6% [50 mg], 65.5% [200/50 mg]). Safety profiles for both treatment groups were consistent with the known safety profile of ritlecitinib.

Conclusion: Ritlecitinib has clinically meaningful and sustained efficacy beyond 1 year with a favourable safety and tolerability profile, supporting its long-term use in patients aged ≥12 years with AA.

Trial registries: ClinicalTrials.gov: NCT03732807, NCT04006457.