Management Considerations: Pharmacologic Intervention

Abstract

Glucocorticoids are considered the mainstay of initial treatment for idiopathic inflammatory myopathy (IIM); however, they have significant limitations including lack of complete response and long-term adverse events. Glucocorticoid-sparing agents are often given concomitantly with other immunosuppressive agents, particularly in patients with moderate or severe disease. First-line conventional immunosuppressive drugs include either methotrexate or azathioprine, and second-line immunosuppressive therapy includes mycophenolate mofetil, tacrolimus or cyclosporine, intravenous immunoglobulin, or rituximab, used alone or in various combinations. As treatment of refractory cases of idiopathic inflammatory myopathies (IIM) has been challenging, there is growing interest in assessing novel biologics that target various pathways implicated in the pathogenesis of IIM. Rituximab is being used off-label with increasing evidence in refractory myositis and associated interstitial lung disease. Antitumor necrosis factor (anti-TNF) is currently not being used in IIM due to uncertain efficacy data. Further research is currently ongoing to evaluate the role of other novel therapies such as tocilizumab (anti-IL6), abatacept (inhibition of T-cell co-stimulation), sifalimumab (anti-IFNα), or tofacitinib (Janus kinase (JAK) inhibitor) given their biological plausibility and encouraging recent small case series results. IVIG is being used either as monotherapy or as combination therapy especially for necrotizing myopathies, and there is an ongoing randomized controlled trial in dermatomyositis (DM).