Real-world effectiveness and safety of baricitinib including its effect on biomarkers and laboratory data in Japanese adult patients with atopic dermatitis: a single-center retrospective study

Baricitinib demonstrated efficacy and tolerable safety in clinical trials for atopic dermatitis (AD); however, real-world data are limited. We examined effectiveness and safety of baricitinib, and laboratory data in AD patients treated with baricitinib in our department. We also evaluated baseline clinical severity in responders and non-responders. All adult AD patients treated with baricitinib in our department between January 2021 and February 2023 were included. Data on 30 Japanese AD patients were analyzed. Objective severity scores and patient-reported outcomes improved at one and 3 months, except for the affected body surface area at 1 month. The proportions of patients who achieved eczema area and severity index-50% improvement were 30.0% (9/30) at 1 month and 53.3% (16/30) at 3 months. There were no significant changes in AD biomarkers. No significant difference was observed in baseline clinical severity between responders and non-responders. No significant changes were observed in laboratory results except for increased serum creatine phosphokinase levels at 3 months. One case of herpes zoster and one case of ocular herpes were observed. Baricitinib showed mild effectiveness and favorable safety including laboratory findings. Biomarkers did not reflect clinical improvement. Further study is needed to identify characteristics of responders.