RESUMEN
BACKGROUND/AIM: Cemiplimab in patients with non-small cell lung cancer (NSCLC) with PD-L1 (programmed death ligand type 1) expression ≥50% showed a significant improved overall survival (OS) with increasing expression of PD-L1. To our knowledge there exist no similar data published for pembrolizumab regarding the increased OS in relation to the PD-L1 expression. Therefore, the objective of our study was to determine whether improvement in OS reflects increased expression levels of PD-L1 (≥50%) in patients with NSCLC. PATIENTS AND METHODS: Retrospective data from 9 Czech and 1 Polish comprehensive oncology Centers were used. All patients with stage IV NSCLC and PD-L1 expression ≥50% treated with pembrolizumab in daily practice were included. The groups of patients according to the expression of PD-L1 were determined as follows: PD-L1 50-59%, 60-69%, 70-79%, 80-89% and 90-100%. The log-rank test and the Cox regression model were used to compare survival between study groups. RESULTS: A total of 617 patients were included in the study. We did not observe a statistically significant difference in OS between groups of patients with different levels of PD-L1 expression in the pooled comparison (p=0.445). Furthermore, we did not observe a statistically significant difference even when comparing OS in patients with PD-L1expression of 50-59% (reference) with the group of other patients according to the level of expression of PD-L1 in the Cox regression model including the effect covariates. CONCLUSION: PD-L1 expression showed no significant effect on OS in patients with NSCLC with PD-L1≥50% treated with pembrolizumab.