Janus kinase inhibitor, tofacitinib, in refractory juvenile dermatomyositis: a retrospective multi-central study in China

Objectives Juvenile dermatomyositis (JDM) is a chronic autoimmune disease. Some patients remain in an active state even though they were administrated with a combination of corticosteroid and methotrexate. Existing research has suggested that interferon and Janus kinase played an important role in pathogenesis. Existing research has suggested the efficacy of JAK inhibitors (JAKi). Our retrospective study aimed to investigate the efficacy of tofacitinib in refractory JDM patients. Methods A total of eighty-eight patients in China who had been diagnosed with JDM and subjected to tofacitinib therapy for over 3 months were retrospectively analyzed. Skin and muscle manifestations were assessed using the Cutaneous Assessment Tool-binary method (CAT-BM), Childhood Myositis Assessment Scale (CMAS), and kinase. Pulmonary function was assessed using a high-resolution CT (computerized tomography) scan and pulmonary symptoms. All patients were subjected to regular follow-up, and core measures were assessed every 3 months after initiation. Furthermore, the data were analyzed using the Wilcoxon single test, Mann-Whitney U test, and chi-square test. Results Compared with the baseline data, skin and muscle manifestations were found significantly improved during the respective follow-up visit. At the most recent follow-up, nearly 50% of patients achieved a clinical complete response and six patients received tofacitinib monotherapy. Sixty percent of patients suffering from interstitial lung disease well recovered on high-resolution CT. Seventy-five percent of patients showed a reduction in the size or number of calcinosis, and 25% of patients showed completely resolved calcinosis. Conclusion In this study, the result suggested that tofacitinib therapy exerted a certain effect on skin manifestations, muscle manifestations, interstitial lung disease (ILD), calcinosis, as well as downgrade of medication. In-depth research should be conducted to focus on the correlation between the pathogenesis of JDM and JAKi. Keywords: Juvenile dermatomyositis, Tofacitinib, Biologic therapy, Janus kinase inhibitor, Refractory