Where are we now in biological drugs for myositis?

Abstract

Idiopathic inflammatory myopathies (IIM) are a rare and heterogeneous group of chronic autoimmune disorders. Up to 40% of IIM patients have long-term sequelae and significant functional disability. Its management can be challenging. New therapies are badly needed. The small number of cases with diverse presentations, and different diagnostic criteria interfere significantly with clinical trial results. Only intravenous immunoglobulin has been internationally approved for IIM patients. Most clinical trials of new biological therapies have failed to meet their primary endpoints in IIM, with only one biological drug recommended for refractory IIM treatment (rituximab), although not approved. We review several new emerging biological drugs including B cell depletion therapies, abatacept, janus-kinase inhibitors, and aldesleukin. Encouragingly, some phase II randomized controlled trials have evaluated the efficacy and safety of new biologics in IIM, demonstrating an improvement in clinical and laboratory measures.