Treatment of refractory polymyositis and dermatomyositis

Abstract

Polymyositis (PM) and dermatomyositis (DM) are autoimmune inflammatory diseases that primarily target muscle. Although similar, PM and DM have different pathophysiologic mechanisms. Current therapy for PM and DM does not take into account these pathophysiologic differences. Recent work has started to define outcome measures to apply to future therapeutic trials, which will allow better comparison of treatment outcomes. For patients who are unresponsive to standard therapy with high dose prednisone supplemented by methotrexate and/or azathioprine it is not clear what represents the next best choice for therapy. Although there are few controlled studies in the area, there is reason to be optimistic for use of intravenous methylprednisolone pulses, intravenous gammaglobulin, cyclosporine A, tacrolimus, mycophenolate mofetil, and rituximab for nonresponding patients. Better understanding of the underlying pathophysiology of PM and DM, as well as carefully performed multicenter clinical trials is going to be necessary to make better recommendations in the future.

Increased serum levels of B cell activating factor (BAFF) in subsets of patients with idiopathic inflammatory myopathies

“…More recently, plasma cells were reported in muscle tissue of polymyositis and patients with IBM 5. A further support for a pathogenic role of B cells in myositis is the beneficial effect of B cell depletion therapy with rituximab in resistant cases of patients with dermatomyositis and polymyositis as described in one open pilot study and several case reports 6 – 13…”

Evaluation of muscles affected by myositis using magnetic resonance elastography

“…Polymyositis (PM), dermatomyositis (DM), and juvenile dermatomyositis (JDM) represent a group of autoimmune inflammatory disorders of the muscle, collectively known as idiopathic inflammatory myopathies (IIMs) 1. Although they differ in pathology, common findings include lymphocytic infiltration, edema within the muscle, and myofiber necrosis on muscle biopsy.…”

The use of cyclosporine in dermatology: Part I

“…Cyclosporine can be used in cases unresponsive to this standard regimen. 106,107 There is no agreement as to the optimum regimen or combination of immunosuppressive agents to treat dermatomyositis. 108 Cyclosporine has been proposed as a second-line agent for both adult and juvenile forms of the disease in those unresponsive to other immunosuppressants, such as methotrexate or azathioprine.…”