Despite a paucity of controlled clinical trials, glucocorticoids remain the mainstay of initial treatment for inflammatory myopathies. Glucocorticoid-sparing agents, either methotrexate or azathioprine, are often begun concomitantly with glucocorticoid therapy. However, in refractory patients other immunosuppressive or immunomodulatory agents such as mycophenolate mofetil, cyclosporine, tacrolimus, and IVIg are used alone or in various combinations. In a large clinical trial of rituximab in adult and juvenile myositis, the primary outcome was not met but most patients met trial criteria of improvement and rituximab use was associated with a significant glucocorticoid-sparing effect. Some of immunosuppressive agents are more appropriately used when certain disease manifestations predominate such as mycophenolate mofetil (interstitial lung disease and refractory cutaneous disease) and tacrolimus or cyclosporine (interstitial lung disease). Anti-TNF drugs have also been studied but the results are not encouraging. ACTH-gel has an FDA approved indication for polymyositis and dermatomyositis with positive results in a small retrospective case series, however, a more definitive trial is ongoing. Novel therapeutic agents are being studies and have shown favorable outcome in case reports and series, but more definitive trials are ongoing or are needed. The future therapeutic options for myositis will depend on well-designed clinical trials using validated outcomes and improvements in classification schemes based on serologic and histopathologic factors.
Disclosure of Interest None declared