Life-threatening cytokine release syndrome after atezolizumab–bevacizumab combination therapy in advanced lung cancer successfully treated with tocilizumab: a case report

Cytokine release syndrome (CRS) is a rare but potentially life-threatening adverse event associated with immune checkpoint inhibitors. We reported a 63-year-old woman who was successfully treated with tocilizumab for grade 4 CRS, which developed after combination chemotherapy-immunotherapy for stage IVA epidermal growth factor receptor -mutated metastatic non-small cell lung cancer. CRS developed during the 10th course of atezolizumab plus bevacizumab and was characterized by fever, rash, hypotension requiring vasopressors, hypoxemia, acute kidney injury, thrombopenia, and coagulation disorder. Suspecting CRS, massive fluid infusion, vasopressor administration, and antimicrobial therapy were initiated. In addition, high-dose intravenous methylprednisolone therapy and weekly tocilizumab for a total of three doses were administered. The patient was admitted to the intensive care unit and managed with non-invasive positive pressure ventilation. Subsequently, severe coagulation disorders developed, leading to cerebral and intramuscular hemorrhage. Transfusion therapy with red blood cells, platelet concentrate, and fresh frozen plasma was administered, along with factor XIII replacement. On the 34th day of hospitalization, her general condition improved, and she was discharged home. CRS caused by atezolizumab is extremely rare, and this case illustrated the importance of early recognition and timely immunosuppressive therapy for life-threatening CRS.