Immune checkpoint inhibitor–induced Triple M syndrome : Myasthenia gravis, myositis and myocarditis

Abstract

Although immune checkpoint inhibitor (ICI) has provided a revolutionary treatment option for many types of cancers, it can induce immune–mediated adverse events (irAEs) due to excessive autoimmune responses. ICI–induced myasthenia gravis (MG), myositis, and myocarditis can also occur concurrently as an overlap syndrome, which is called Triple M syndrome, and known as rare but one of the most severe and life–threatening irAEs. Thymoma can also be associated triple M syndrome, and ICI–induced and thymoma–associated Triple M syndrome may share a common immunopathogenesis. Some patients with Triple M syndrome are refractory to a comprehensive treatment including corticosteroids, intravenous immunoglobulin, plasmapheresis. When the conventional immunotherapies are insufficient to control severe irAE, biologics represent potential therapeutic options. However, the molecular targeted therapies haven't been established. The establishment of treatment based on the molecular mechanism is highly desirable.