Systematic Review and Indirect Treatment Comparisons of Ritlecitinib against Baricitinib in Alopecia Areata

Ritlecitinib and baricitinib are recently approved systemic treatments for severe alopecia areata (AA). Both demonstrated superiority over placebo in hair regrowth measured by the Severity of Alopecia Tool (SALT), but they have not been directly compared in randomised controlled trials (RCTs). We conducted a systematic review of RCTs evaluating treatments in AA and estimated the efficacy and safety of ritlecitinib and baricitinib at Week 24 using Bayesian network meta-analysis (NMA). To adjust and explore effect modifiers, population-adjusted indirect comparison was performed via multi-level network meta-regression (ML-NMR) using ritlecitinib Individual Patient Data (IPD). Co-primary endpoints were SALT≤20 and SALT≤10 at Week 24. Unanchored population adjusted ITCs were also computed, to evaluate SALT≤10 and SALT≤20 endpoints at Week 48/52. Four RCTs (ALLEGRO 2a [NCT02974868], ALLEGRO 2b/3 [NCT03732807], BRAVE-AA1 [NCT03570749] and BRAVE-AA2 [NCT03899259]) were included. No evidence of a difference between ritlecitinib 50mg and baricitinib 4mg on SALT≤10 (odds ratio (OR): 0.96, 95% credible interval (CrI): 0.18 - 7.21 and SALT≤20 (OR: 2.16, 95% CrI: 0.48 - 16.46) at Week 24 was found. ML-NMR using ALLEGRO IPD adjusted for sex, SALT score at baseline, duration of current episode and disease duration found evidence of effect modification, although relative efficacy between ritlecitinib 50mg and baricitinib 4mg remained unchanged. Unanchored population adjusted ITC at Week 48/52 was consistent with previous results. We found similar efficacy between ritlecitinib 50mg and baricitinib 4mg. These ITCs was informed by only four RCTs, uncertainty was considerable, and there was evidence of effect modification, highlighting the need for further quality research in AA.