103PComparison of continuous measures across diagnostic PD-L1 assays using image analysis
T. Wiestler, M. Widmaier, J. Walker, C. Barker, M. Scott, F. Sekhavati, A. Budco, K. Schneider, K. Steele, M.C. Rebelatto , Annals of Oncology , DOI: 10.1093/annonc/mdx363.019
Background: Tumour programmed cell death ligand-1 (PD-L1) expression is a key biomarker in identifying patients who may have an enhanced response to non-small cell lung cancer treatment using anti-PD-1 (e.g. nivolumab and pembrolizumab) or anti-PD-L1 (e.g. atezolizumab and durvalumab). Each treatment is currently used in conjunction with an individual PD-L1 diagnostic immunohistochemistry (IHC) assay and it is unclear whether immunolabelling parameters determined by pathologists are comparable across assays. We extended previous studies (Ratcliffe et al Clin Cancer Res 2017; Ratcliffe et al ASCO-SITC 2017 [abstr 7]) by performing image analysis (IA) with a customised PD-L1 scoring solution to permit a quantitative comparison of the 4 PD-L1 IHC assays.
Methods: We developed an IA scoring algorithm that enabled us to quantify the percentage of positive tumour cells on a whole slide...