PD-L1 assay characteristics and performance in NSCLC

Assay	Antibody	FDA-approved Indication in NSCLC	Cutoff Value	Performancea
22C3 IHC pharmDx	Monoclonal mouse anti-PD-L1, Clone 223	Approved as a companion diagnostic to select patients with advanced NSCLC for treatment with pembrolizumab first-line (TPS ≥ 50%) or after progression on a platinum containing chemotherapy regimen (TPS ≥ 1%)	• TPS < 1% PD-L1 negative• TPS 1–49% PD-L1 positive• TPS ≥ 50% High PD-L1 expression	Found to be closely aligned with 28–8 and SP263 IHC assays
28–8 IHC pharmDx	Monoclonal Rabbit anti-PD-L1, Clone 28–8	Approved as a complementary diagnostic to aid in non-squamous NSCLC patient selection for treatment with nivolumab	Qualitative test reported as a percentage of tumor cells exhibiting positive membrane staining	Found to be closely aligned with 22C3 and SP263 IHC assays
PD-L1 (SP142) Assay	Monoclonal Rabbit anti-PD-L1, Clone SP142	Approved as a complementary diagnostic to aid in NSCLC patient selection for treatment with atezolizumab	PD-L1 expression in ≥ 50% tumor cells or ≥ 10% immune-infiltrating cells is associated with enhanced survival	Consistently stained fewer PD-L1 tumor cells
PD-L1 (SP263) Assay	Monoclonal Rabbit anti-PD-L1, Clone SP263	CE mark only, not approved by the FDA for patients with NSCLC	The CE mark was granted and expanded based on demonstrated equivalency to the 28–8 and the 22C3 IHC assays	Found to be closely aligned with 22C3 and 28–8 IHC assays

Abbreviations IHC immunohistochemistry, NSCLC non-small cell lung cancer, PD-L1 programmed cell death ligand 1, TPS tumor proportion score

^aAs assessed in Phase I of the Blueprint PD-L1 IHC assay Comparison Project [56]