Clinical Issue of Myasthenia Gravis Related to Immune Checkpoint Inhibitors

Immune-related adverse events (irAEs) are pivotal in the management of immune checkpoint inhibitors (ICIs) across various human neoplasms. While common irAEs are manageable by oncologists, the detailed features of rare complications related to ICI therapy remain elusive. Among these, immune-related myasthenia gravis (irMG) stands out as a life-threatening disease.

Research articles published in English between 2017 and 2023 were identified using the PubMed database. Forty-six relevant research studies were examined to collate information for this review. The incidence of ICI-induced MG was found to be less than 1.0%, with approximately 20-30% of irMG patients presenting with overlap syndrome involving myocarditis and myositis. The detection of acetylcholine receptor antibodies (AChR-Ab) and elevated creatinine kinase (CK) levels proved useful in identifying 50-70% and 60-80% of cases, respectively. However, the utility of muscle-specific kinase antibodies (MuSK-Ab) in detecting irMG was limited due to a low positivity rate (0-5.3%). Ptosis emerged as the most common initial symptom of irMG, with an approximate positivity rate of 80%. Recommended treatment for irMG involves high-dose steroids in conjunction with plasmapheresis or immunoglobulins to mitigate the increased mortality associated with irMG. Early initiation of immunosuppressive therapy is imperative to prevent the worsening of irMG. Furthermore, facilitating a fulfilling social life post-hospitalization is crucial. This review sheds light on the clinical aspects and management strategies pertaining to irMG.