Treatment of myositis with etanercept (Enbrel^®), a recombinant human soluble fusion protein of TNF-α type II receptor and IgG1

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Department of Rheumatology and Institute of Physical Medicine, University Hospital Zurich and ¹Institute of Neuropathology, University Hospital Zurich, Zurich, Switzerland

Sir, Polymyositis is an inflammatory myopathy that is related to progressive, proximal, symmetrical muscle weakness, increased concentrations of serum muscle enzymes, an abnormal electromyogram and an abnormal muscle biopsy showing inflammation. Standard drug therapy includes high-dose corticosteroids and immunosuppressive drugs (methotrexate, azathioprine or even cyclophosphamide). Recent data are in favour of the early introduction of a cytotoxic or immune-modulating drug in addition to corticosteroid therapy. In patients with corticosteroid- and immunosuppressive-resistant myositis, management approaches include intravenous high-dose pulse methylprednisolone combined with immunosuppressive drugs, and combination therapy with methotrexate and azathioprine, cyclosporin and/or intravenous immunoglobulin (Ig). Lack of efficacy occurs in some cases. Recent advances in the understanding of the role of cytokines and complement in the pathogenesis of myositis have led to preliminary therapeutic trials of biological agents: etanercept, infliximab and anti-C5 monoclonal antibody [1].