トルリパリブとアキチニブ併用療法による致命的な心筋炎の症例報告

Cardiac immune-related adverse events (irAEs) are rare but potentially life-threatening complications of immune checkpoint inhibitor (ICI) therapy, with myocarditis associated with particularly high mortality even under aggressive treatment.

A 65-year-old male with advanced clear cell renal cell carcinoma and liver metastasis presented with progressive wheezing and fatigue following 4 cycles of combination therapy with toripalimab and axitinib, symptoms that failed to respond to conventional supportive measures.

Grade 4 ICI-associated myocarditis was confirmed through a combination of clinical manifestations, characteristic echocardiographic abnormalities, elevated cardiac biomarkers, and the exclusion of infectious causes via comprehensive serological evaluation.

The patient received multimodal immunosuppressive and supportive therapy, including high-dose methylprednisolone, intravenous immunoglobulin (IVIG), venoarterial extracorporeal membrane oxygenation (VA-ECMO), and therapeutic plasma exchange. Concurrently, broad-spectrum antibiotics were administered based on continuous microbial surveillance.

Although transient hemodynamic stabilization was achieved, the patient subsequently developed severe nosocomial infections and progressive multiorgan failure, leading to death on day 24 of hospitalization.

This case underscores the necessity for early recognition and intensive monitoring in managing high-grade ICI-associated myocarditis. It further highlights the critical role of infection prevention strategies, particularly the implementation of microbial surveillance-guided antibiotic prophylaxis, in patients undergoing combination immunotherapy regimens.

We report a 65-year-old male with advanced renal cell carcinoma who developed ICI-associated myocarditis following 4 cycles of combination immunotherapy. The patient presented with progressive dyspnea and fatigue, necessitating hospitalization. Comprehensive diagnostic evaluation confirmed grade 4 myocarditis based on clinical features, elevated cardiac biomarkers, echocardiographic abnormalities, and exclusion of infectious causes. Treatment consisted of multimodal immunosuppressive and life-support therapies, including high-dose methylprednisolone, intravenous IVIG, therapeutic plasma exchange, VA-ECMO, and empiric broad-spectrum antibiotics guided by microbial surveillance. Despite transient hemodynamic stabilization, the patient ultimately progressed to multiorgan failure and died on day 24 of hospitalization. This case underscores the life-threatening nature of ICI-associated myocarditis and highlights the critical need for early recognition, aggressive supportive management, and proactive anti-infective prophylaxis in patients receiving combination immunotherapy.