Current Treatment of Myasthenia Gravis

Abstract

Myasthenia gravis (MG) is the most extensively studied antibody-mediated disease in humans. Substantial progress has been made in the treatment of MG in the last century, resulting in a change of its natural course from a disease with poor prognosis with a high mortality rate in the early 20th century to a treatable condition with a large proportion of patients attaining very good disease control. This review summarizes the current treatment options for MG, including non-immunosuppressive and immunosuppressive treatments, as well as thymectomy and targeted immunomodulatory drugs.

Keywords: azathioprine; beta adrenergic; corticosteroids; cyclophosphamide; cyclosporine; eculizumab; efgartigimod; intravenous immunoglobulin; methotrexate; myasthenia gravis; plasma exchange; prednisone; pyridostigmine; stem cell transplant; tacrolimus; terbutaline.

Figure 1

Azathioprine metabolism. Deficiency of thiopurine methyltransferase results in increased 6-thioguanine levels, which may result in myelosuppression. On the other hand, increased activity of thiopurine methyltransferase will lead to increased levels of 6-methylmercaptopurine, which predisposes to hepatotoxicity (hypermethylation). Allopurinol can result in severe leukopenia if administered with the usual dose of azathioprine as it inhibits xanthine oxidase.

Figure 2

Overall treatment strategy of myasthenia gravis. MuSK: muscle specific tyrosine kinase; Ab: antibody; AChR: acetylcholine receptor; IVIG: intravenous immunoglobulin; PLEX: Plasma exchange.