Update on the pharmacological treatment of adult myositis

The management of patients with idiopathic inflammatory myopathy (IIM) remains a challenge given the systemic features beyond active myositis. That is, recognizing the inflammatory arthropathy, varying dermatomyositis rashes, and overt and occult features of interstitial lung disease in addition to myositis adds to the complexity of diagnosis and treatment of IIM. However, clinicians now have available many more immunosuppressive drugs as well as biologic agents for use in patients with myositis and other autoimmune diseases. Here, the use of these agents is reviewed and support based on available published literature is provided even though many studies have been small and results somewhat anecdotal. Glucocorticoids remain the initial treatment of choice in most instances and methotrexate and azathioprine are often used early in the treatment course. These agents are followed by other immunosuppressive drugs, for example mycophenolate mofetil, tacrolimus, cyclosporine and cyclophosphamide, some of which are used alone while combinations of these agents also provide an effective option. There is more rationale for the use of biologic agents such as rituximab from a mechanistic perspective and, given the incorporation of validated core set measures in assessing myositis patients, we can look forward to better designed clinical trials in the future.