Tumor Response to Immune-Oncology Therapy Despite High-Dose Steroid Intervention in a Patient With Papillary Renal Cell Carcinoma and Immune-Related Myasthenia Gravis

Immune-oncology (IO) therapies, particularly immune checkpoint inhibitors, have significantly altered the treatment landscape for various cancers, including renal cell carcinoma (RCC). Unfortunately, immune-related adverse events (irAEs) during therapy often necessitate corticosteroid intervention, which may theoretically impair the anti-tumor immune response. In this article, we describe a unique case in which a patient with advanced papillary RCC developed immune-related myasthenia gravis (MG) while on nivolumab (a PD-1 inhibitor) and cabozantinib. Even while giving corticosteroid treatment for myasthenia gravis, the patient exhibited a striking treatment response, with substantial tumor shrinkage and regression of regional lymphadenopathy. This case highlights that IO agents can remain efficacious even in the presence of significant immunosuppression, raising important mechanistic and clinical considerations for managing irAEs.