Baricitinib Effectiveness in JAKi‐Naïve and Tofacitinib‐Exposed Patients: A Prospective Study in Alopecia Areata

Background Janus kinase inhibitors (JAKi) have substantially modified the treatment paradigm for alopecia areata (AA). However, the response to switching between these agents following therapeutic failure remains poorly defined. Objective This study aimed to evaluate the effectiveness and safety of baricitinib in patients with AA previously treated with tofacitinib, compared with JAKi‐naïve individuals. Methods A prospective, observational, single‐centre study was conducted. Demographic, clinical, and therapeutic variables were collected to compare the two groups. Statistical analysis included univariate ANOVA and MANOVA to assess longitudinal intra‐ and intergroup changes. Results A total of 44 patients with severe AA treated with baricitinib were included. The mean age was 37.7 years (standard deviation [SD]: 16.1), and 65.9% (29/44) were female, resulting in a female‐to‐male ratio of 2:1. The mean baseline Severity of Alopecia Tool (SALT) score was 67.2 (SD: 32.6). Of these patients, 22.7% (10/44) had previously been treated with tofacitinib for a mean duration of 33.30 months (SD: 11.47). Stratified multivariate MANOVA revealed a significant reduction in SALT scores over time in the JAKi‐naïve group ( p = 0.007), whereas no statistically significant changes were observed in patients previously exposed to tofacitinib ( p > 0.20). Among the latter, most maintained or slightly improved their clinical status under baricitinib. Notably, 75% of the patients with residual disease after tofacitinib responded to baricitinib, while 25% did not. No relapses occurred in patients who had achieved satisfactory disease control with tofacitinib. Adverse event rates were comparable between both groups, with no clinically relevant differences observed. Conclusions Our findings suggest that baricitinib is significantly more effective in JAKi‐naïve patients with AA compared with those previously exposed to tofacitinib. Switching between JAKi appears to be a safe and potentially beneficial strategy in selected patients, particularly those with partial prior responses. As this study has a limited sample size and is noncontrolled, further studies are warranted to confirm these results and guide optimal sequencing of JAKi therapy in clinical practice.