Rotate your device to portrait mode.
D-1/PD-L1 directed antibodies are emerging as effective therapeutics in multiple oncology settings. Multiple diagnostic PD-L1 tests are being used to understand how PD-L1 expression predicts response to these therapies. It is vital to compare these assays to understand the risk if assays are used interchangeably. Tumor cell (TC) PD-L1 expression by the Ventana SP263 and the Dako 28-8 and 22C3 assays has proven concordant at multiple clinically relevant cut offs.(Ratcliffe et al AACR 2016 [LB-094]); (Ratcliffe et al ESMO 2016 [955PD]). The current study builds on the previous study by inclusion of immune cell (IC) scoring and the Ventana SP142 assay.
493 tumor biopsy samples from NSCLC patients stained with the Ventana SP263 and Dako 22C3 and 28-8 were scored for IC PD-L1 expression, calculated as % of infiltrating IC expressing PD-L1 at any intensity. A subset of 200 tumor blocks from this cohort were sectioned and stained with SP142 and serial sections restained with SP263 to ensure an appropriate comparison. Concordance between IC and TC between these 2 assays is reported.
There was strong agreement in IC scoring with the Ventana SP263 and Dako 22C3 and 28-8 assays. The SP142 assay showed lower concordance for IC and reduced TC PD-L1 staining/concordance vs SP263 (Table).
This study shows analytical similarity between the Ventana SP263, Dako 28-8 or 22C3 assays when measuring TC or IC PD-L1 expression, and high concordance between patient classification at matching TC or IC cut offs. This strengthens the evidence that these 3 assays could be used interchangeably. The Ventana SP142 assay shows clear analytical differences for both IC and TC staining, suggesting it is not appropriate to interchange with the other assays.
© 2017 by American Society of Clinical Oncology