Association analysis of the combination of tumor burden and PD-L1 expression and response to PD-1/L1 inhibitors in Chinese cancer patients.

e13520Background: PD-1/L1 inhibitors have demonstrated their remarkable clinical efficacy in multiple tumors. PD-L1 expression and tumor mutation burden (TMB) are the most studied biomarkers for immune check point inhibitors in western cohort. However, sufficient evidences are still lacking in Chinese cancer patients (pts). Methods: Totally 32 advanced cancer pts including 19 NSCLC, 11 intrahepatic cholangiocarcinoma, 1 hepatocellular carcinoma and 1 gastric cancer who received anti-PD-1/PD-L1 treatment as multi-line therapies were recruited. Genomic alterations were assayed by deep sequencing panel assay targeting the whole exons of 450 cancer genes and selected introns in 39 genes. TMB was acquired by NGS algorithm. Tumor tissues from selected patients were analyzed for PD-L1 expression by IHC. Results: The median age of the 32 pts was 53.5 years (range: 35-69) including 23 males and 9 females. These patients were administrated for FDA approved PD-1/L1 inhibitors with or without chemo or antiangiogenesi...