Immunological Variables Associated to ICI Toxicity in Cancer Patients

Advances in treating patients with immunotherapy has dramatically changed cancer morbidity and mortality. Immune checkpoint inhibitors (ICI), alone or combined with other drugs, are currently used both as standard of care or in experimental settings for various cancers. Currently, ICI treatment induces objective clinical responses in 20-40% of patients, which varies by tumour type. A significant risk of immune-related adverse events (irAE) is also associated with ICI treatment, including the onset of autoimmune diseases. While the incidence of irAE is highly variable and influenced by many factors, phase I and II trials reported rates from 10% to 80% for any grade irAE while an irAE of grade 3 or higher was observed in 2.5% to 18% of subjects. Despite the fact that older adults represent the growing majority of patients diagnosed with cancer, the efficacy and toxicity of ICI in older patients, alone or in combination with other agents, remains controversial. Presently, the specific immune mechanism(s) driving irAE are unknown and biomarkers that predict their onset, particularly high-grade irAE, are urgently needed. The identification of predictive clinical, laboratory and immunological biomarkers (blood and tissue) for toxicity will more accurately identify and quantify patients who are at risk for ICI therapy. Then, this will possibly allow better irAE management.