Immune checkpoint inhibitor-associated myositis and myasthenia gravis overlap: Understanding the diversity in a case series.

Immune checkpoint inhibitors (ICI) have improved survival across tumor types however they cause immune-related toxicities through removal of the inhibition of auto-reactive T cells. In this case review, we present 4 patients with metastatic cancer who developed de-novo neuromuscular side effects of myositis with overlapping seropositive myasthenia gravis after ICI treatment. Declaration: This study was performed in accordance to the ethical standards set by the SingHealth Institutional Review Board, with consent taken from living patients and waiver of consent from deceased patients (CIRB Ref 2019/2485). Supporting data were collected from our institution's digital medical records system.