Partial Response to Nivolumab and Ipilimumab in a Patient With Malignant Pleural Mesothelioma and Pre‐Existing Myasthenia Gravis Without Severe Flares or Immune‐Related Adverse Events: A Case Report

Detailed clinical data on the combination immune checkpoint inhibitor (ICI) therapy in patients with myasthenia gravis (MG) remain limited. We report a case of malignant pleural mesothelioma with previously undiagnosed ocular MG. Owing to hepatic dysfunction, reduced doses of nivolumab and ipilimumab were administered before confirmation of anti-acetylcholine receptor (AChR) antibody positivity. MG was diagnosed based on subtle ocular symptoms and serological tests. Prophylactic intravenous immunoglobulin and an acetylcholinesterase inhibitor were administered; combination therapy was discontinued owing to the risk of MG flare, but a partial tumour response was achieved. With disease progression, nivolumab monotherapy was reintroduced, and early steroid pulse therapy was administered owing to elevated creatine kinase, again inducing a partial response. Serological screening for anti-AChR antibodies may help prevent severe MG flares and immune-related adverse events. With caution, dose-reduced and limited-exposure ICI combination therapy may be feasible in selected patients with MG under appropriate prophylactic management.