Outcomes in checkpoint inhibitor induced neuromuscular immune related adverse events: A case series

Immune-checkpoint inhibitors, a mainstay of treatment of solid tumors, rarely lead to activation of the host immune system against another target, causing autoimmune inflammation of other end organs known as immune-related adverse events (ir-AEs). When ir-AEs are directed at the neuromuscular system, clinical consequences include myositis and myasthenic syndromes. In this article, we describe three cases presenting with neuromuscular ir-AEs. Two patients had lung adenocarcinoma and were treated with pembrolizumab. One patient had gastroesophageal junction adenocarcinoma treated with nivolumab. Each were found to be seropositive for an autoantibody implicated in myasthenia gravis. All patients came off immunotherapy, halted cancer-directed treatments, and transitioned to comfort care following ir-AE onset. We emphasize that while most described neuromuscular ir-AE cases improve with treatment, in a subset of patients, neuromuscular ir-AEs lead to termination of cancer-directed care and transition to comfort care. To our knowledge, this study is the first in the literature to look specifically at a group of patients who withdrew attempts at curative therapy following neuromuscular ir-AE diagnosis. Better understanding of neuromuscular ir-AE treatment and identification of patients at higher risk for neuromuscular ir-AEs are needed.