Immunotherapy Related Adverse Events Predict Treatment Response

Immunotherapy blocks immunoinhibitory pathways and allows for reversal of immunosuppression caused by malignant tumors. Immunotherapy can cause immune-related adverse events (IrAE) including rash, pneumonitis, colitis endocrinopathy, nephritis, adrenal insufficiency, hepatitis, and uveitis. Limited data exist to predict which patients will have the greatest response to therapy and if there is a correlation between IrAE and immunotherapy effectiveness. The aim of this study was to determine the relationship between IrAE and immunotherapy efficacy. A retrospective medical records review was collected of patients with metastatic cancer who received immunotherapy. Data included demographics, Eastern Cooperative Oncology Group Performance Status, imaging, time on treatment, best response, disease progression, and presence or absence of IrAE while on treatment. Treatment response was analyzed using the Response Evaluation Criteria in Solid Tumors guideline, version 1.1. Overall survival probabilities were calculated by the Kaplan-Meier survival method. 456 patients were included for analysis, 175 (38.4%) had an IrAE while on immunotherapy. The development of IrAE correlated with response rate for complete response, partial response, and overall response rate. A significant increase in overall survival was also seen. The presence of IrAE may be a potential predictive indicator for treatment response to immune checkpoint inhibitors.