Onkológia 2/2017

Clinical significance of PD-L1 immune check-point measurement

PD-L1 ligand expressed on tumor cell is not only ligand for PD1 and cofactor of inhibition of immune-response cells but also diagnostic biomarker predictive for response and prognostic factor for progression free survival (PFS) overall response rate (ORR) and overall survival (OS). Validated diagnostic tests are used predominantly IHC diagnostic methods with different antibodies. Frequency of positivity creates stratified cohorts with different levels of positivity or negative one. Analysing phase II. studies in second line therapy of nonsmall cell lung cancer with nivolumab (CHECKMATE 017 a 057), pembrolizumab (KEYNOTE 001 a 010) and atezolizumab (POPLAR) results are superior in effectivity, PFS and OS in subgroup of patients with higher expression of PD-L1. Median OS in squamous histology using nivolumab in subgroup with PD-L1 >10% was 11 vs. 8,2 month in subgroup with PD-L1<10%, and in non-squamous histology 19,4 vs. 8 month. Using pembrolizumab in subgroup with high expression of PD-L1 mOS was 14,9 month and in study with atezolizumab mOS in subgroup with positivity PD-L1 was 15,5 month versus 9,7 month in subgroup with negative expression.

Keywords: measurement of PD1-L1 levels, nivolumab, pembrolizumab, atezolizumab