Spatial Biomarkers and Immunotherapy Response

Delivering on the promise of precision medicine in oncology depends on the predictive performance of biomarker tests. Immuno-oncology treatments can be lifesaving – but only for a fraction of patients. Put simply, the predictive biomarkers available today don’t always accurately identify the patients who will respond, leading to higher incidences of adverse events and treatment resistance. Conventional immunohistochemistry (IHC) techniques assessing PD-L1 expression and, to a lesser degree, microsatellite instability status are currently the only clinically validated predictive biomarkers for checkpoint inhibitors. However, most experts agree that neither assay is sufficient; some lead to false positives or false negatives, whereas others address only a small fraction of the patient population. There is much room for improvement.