Successful Treatment of Anti-Jo-1 Positive Inflammatory Myopathy With Tofacitinib.

Idiopathic inflammatory myopathies are, in some cases, refractory to all guideline-based treatments, posing a very difficult challenge in clinical practice. Janus kinase inhibitors are a rather new class of disease-modifying antirheumatic drugs that are approved for the treatment of rheumatoid arthritis, spondyloarthritis, and psoriatic arthritis, but have been used as an off-label treatment only in a very limited number of cases in inflammatory myopathies. In this case report, we present a middle-aged woman with severe muscle weakness and pain attributed to refractory myositis associated with anti-Jo-1 antibody. Despite multiple treatment attempts, which included all guideline-based immunosuppressants, the patient's condition remained unresponsive. Initiation of tofacitinib therapy resulted in significant clinical improvement, normalization of creatinine kinase levels, and being possible to discontinue glucocorticoids. Our findings highlight the potential efficacy of tofacitinib in refractory inflammatory myopathies, and to our knowledge, our case is the first one to demonstrate the efficacy of a Janus kinase inhibitor in anti-Jo-1 positive myopathy without interstitial lung disease.