PD-L1 as a biomarker in NSCLC: challenges and future directions

The Food and Drug Administration (FDA) approval of immune checkpoint inhibitors has dramatically changed treatment paradigms for patients with advanced-stage or metastatic non-small cell lung cancer (NSCLC). Despite significant improvements in survival, the majority of NSCLC patients fail to respond to checkpoint inhibitors, notably antibodies targeting programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1), and uncertainties remain regarding how best to use these therapies in clinical practice. Given the risk of immune-related and other adverse effects associated with treatment, there is a need to identify biomarkers to predict which patients will and will not benefit.