重症筋無力症の最新治療

抄録

Myasthenia gravis (MG) is an autoimmune disease in which neuromuscular transmission is impaired by the action of autoantibodies against target antigens on the postsynaptic membrane. The clinical subtypes of adult–onset MG are broadly divided into ocular and generalized types, Treatment strategies differ between ocular (oMG) and generalized MG (gMG). The Japanese clinical guidelines recommend setting treatment strategies to achieve “MM-5mg” as an earlier, more achievable treatment goal that prioritizes patient quality of life. In gMG, early fast–acting treatment strategy recommended to improve MG symptoms as soon as possible and minimize the use of oral steroids. Furthermore, the administration of molecular target drugs centered on monoclonal antibody agents is considered in cases where current immunotherapy combinations fail to achieve treatment goals. This article focuses on the latest molecular target drugs including anti–complement drugs and neonatal Fc receptor (FcRn) inhibitors for gMG. Regarding anti–complement drugs, while issues remain a fatal adverse event and insufficient investigation into the proportion of non–responders, these agents hold the potential to be highly effective even for the most severe gMG cases. The anti–FcRn inhibitors, which are covered by insurance for MuSK antibody–positive MG and double seronegative MG in Japan, are easy to monitor due to their low incidence of serious adverse events. The introduction of subcutaneous formulations has reduced treatment time in outpatient settings and enabled home self–injection. In clinical practice, molecular target drugs are being introduced for gMG cases where patients wish to minimize impact on lifestyle factors such as employment, or to reduce oral steroids that had previously been difficult to sufficiently taper. There may be a tendency for the introduction of molecular target drugs to be accelerated because of healthcare constraints like immunoglobulin shortages and difficulties in performing plasma exchange.