Abstract 77P
Background
Previous studies have investigated the potential clinical relevance of soluble forms of programmed cell death-1 (sPD-1) and programmed cell death-ligand 1 (sPD-L1) in various immunotherapy-treated solid tumors, including non-small cell lung cancer (NSCLC), with controversial results. We herein aimed to further clarify the prognostic and predictive value of baseline and post-treatment levels of sPD-1 and sPD-L1 in patients with advanced NSCLC treated with immune checkpoint inhibitors (ICIs).
Methods
55 patients with advanced NSCLC eligible to receive immunotherapy (as monotherapy or in combination with chemotherapy) were prospectively enrolled. A group of sex- and age-matched healthy controls (n=16) was also recruited, for determination of the optimal cut-off value of the examined biomarkers. Serum sPD-1 and sPD-L1 levels were measured in peripheral blood samples using ELISA, both at baseline and at the time of treatment response evaluation, and were correlated with prognosis (PFS, OS), treatment response and the remaining clinicopathological features of patients.
Results
Mean age of patients was 66.5 years (SD=8.0 years); 65,5% of patients received chemotherapy and pembrolizumab combination while the remaining patients received pembrolizumab monotherapy. Levels of sPD-1 after treatment were found to be significantly increased as compared to baseline (p<0,001). A minimal increase of mean sPD-L1 levels after treatment was also observed, albeit without reaching statistical significance. Univariate Cox regression analysis showed that increased pre-treatment values of sPD-1 (HR=10.96; p=0.037) and sPD-L1 (HR=1.68; p=0.040) were significantly associated with reduced OS. However, only sPD-L1 retained its prognostic significance in multivariate analysis (HR=2.10; p=0.014).
Conclusions
Increased pre-treatment values of sPD-L1 may independently predict a worse OS in advanced-stage NSCLC patients treated with ICIs.
Legal entity responsible for the study
National & Kapodistrian University of Athens.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.