Biomarkers for Response to Immune Checkpoint Blockade

Immune checkpoint blockade (ICB) has significant clinical activity in diverse cancer classes and can induce durable remissions in even ret advanced disease. However, only a minority of cancer patients treated wit ICH have long-term benefits, and ICI-3 treatment is associated with significant, potentially life-threatening, autoimmune side effects. 'Illere is a great need to develop biomarkers of response to guide patient selection to 1111Ximiy,e the chance of benefit prevent unnecessary toxicity, and current biomarkers do not have optimal positive or negative predictive value. A Variety of potential biomarkers are currently being developed, including those based on assessment of checkpoint protein expression, evaluation of tumorintrinsic features including- mutation burden and viral infection, evaluation of features of the tumortumorlllllllnllenllcroenvirolllllent including nature of immune cell infiltration, and features of the host such as composition of the gut microbiome. Better understanding of the underlying fundamental mechanisms of immune response and resistance to ICY,, along with the use of complementary assays that interrogate distinct features of the tumor, the tumor inicroenvironment, and host immune system, will allotn more precise use of these therapies to optimize patient outcomes.