TABLE II.

PD-L1 testing method and prevalence of PD-L1 positivity in the included studies

Reference	PD-L1 assay		Target cell population	PD-L1 expression (%)
	Developer	Antibody clone for IHC		Threshold	Positive	Negative
Anti–PD-1 trials
Sharma et al., 201623	Dako	28-8	TCs	≥1	37	63
Balar et al., 201724	Agilent	22C3	TCs and ICs	≥10	30	70
				≥1	83	17
Plimack et al., 201710	Dako	22C3	TCs and ICs	≥1	84	16
Sharma et al., 201725	Dako	28-8	TCs	≥1	46	54
				≥5	31	69
Anti–PD-L1 trials
Balar et al., 201722	Ventana	SPI-142	ICs	≥1	67	33
				≥5	27	73
Perez-Gracia et al., 201726	Ventana	SP-142	ICs	≥1	67	33
				≥5	32	68
Powles et al., 201727	Ventana	SP-263	ICs or TCs	≥25	55	45
Pal et al., 201828	Ventana	SP-142	ICs	≥5	52	48
Patel et al., 201829	Dako	73-10	TCs	≥5	45	55
Petrylak et al., 201830	Ventana	SPI-142	ICs	≥5	53	7

IHC = immunohistochemistry; TCs = tumour cells; ICs = immune cells.