Abstract: Objective: To evaluate the efficacy and safety of JAK1/2 inhibitors in the treatment of adult patients with dermatomyositis (DM). Methods: Patients with DM who visited the Department of Dermatology Dermatology Hospital of Southern Medical University Hospital of Dermatology from May 2020 to December 2022 were collected. The Disease Area and Severity Index (CDASI) score was assessed by dermatologist before starting treatment. Meanwhile, skin rash photos were collected and blood routine, biochemical indexes, anti-nuclear antibody, anti-nuclear antibody spectrum, and myositis specific antibody were examined. After contraindications were excluded, oral baritinib 2 mg/d was administered for 12 weeks.  At 4, 8, and 12 weeks after treatment, CDASI scores were evaluated, relevant indicators were reviewed, and adverse events were recorded. Results: Seven patients with DM were included, and six patients completed 12 weeks of drug treatment and follow-up observation. The CDASI scores of all the patients showed a continuous downward trend after treatment, and the continuous improvement could be maintained until the 12th week. Some patients showed a decrease in muscle enzyme index, but it was not statistically significant. After 12 weeks of treatment, some patients with myalgia and/or muscle weakness improved their symptoms. The index of muscle enzyme decreased in some patients, but there was no statistical significance. There were no serious adverse events in patients during the follow-up period. Conclusion: JAK1/2 inhibitors may provide a safer and more effective option for the adult DM patients with poor response to hormone or need to be treated with hormones or other systemic drugs.

Key words: dermatomyositis, Janus kinases, protein kinase inhibitors, JAK1/2 inhibitors