Biomarkers for immune checkpoint inhibitors in advanced nonsmall cell lung cancer

Purpose of review Immune checkpoint inhibitors have been established as a new class of anticancer drugs for patients with advanced nonsmall cell lung cancer. Predictive biomarkers might help to select those patients who will derive the greatest benefit from these expensive drugs. This review summarizes the current status of predictive biomarkers for immune checkpoint inhibitors in advanced nonsmall cell lung cancer. Recent finding Programmed death ligand 1 (PD-L1) staining on tumor cells and immune cells has been studied as a predictive biomarker for immune checkpoint inhibitors. Higher PD-L1 levels appeared to be associated with greater benefit from these drugs in many studies, although such an association was absent in some studies. Tumor mutational load was associated with benefit from the combination of nivolumab plus ipilimumab. Immune checkpoint inhibitors combined with first-line chemotherapy improved survival compared to chemotherapy alone. These improvements were clinically relevant also in patients with PD-L1 expression in less than 1% of tumor cells. Summary PD-L1 expression on tumor and immune cells and tumor mutational load allow better selection of patients for treatment with immune checkpoint inhibitors as single agents. The role of PD-L1 for the selection of patients for chemoimmuntherapy remains to be seen.