Prevalence of PDL1 Amplification and Preliminary Response to Immune Checkpoint Blockade in Solid Tumors

Abstract

Checkpoint blockade with anti–programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) and anti–cytotoxic T-lymphocyte–associated protein 4 (CTLA4) antibodies has revolutionized the treatment of solid and hematologic malignant tumors. However, immune checkpoint inhibitors are only effective in a subset of patients. Biomarkers for determining response to PD-1/PD-L1 blockade include PD-L1 expression,^1,2 microsatellite instability (MSI),³ and a high tumor mutational burden (TMB).^4-6