Table 1. Characteristics of primary AML specimens and effect of activating CD28 antibody on AMG 330-induced cytotoxicity.

Sample	Age (years)	Cytogenetic risk	Baseline phenotyping							Specific cytotoxicity
			AML blasts (%)	CD33 (MFI)	PD-L1 (MFI)	PD-L2 (MFI)	CD80 (MFI)	CD86 (MFI)	CD3+ cells (%)	Control	+CD28 antibody
1	63.0	Intermediate	94.0	1059	21	0	19	6	1.2	10.3	18.8
2	65.7	Intermediate	91.0	408	25	3	9	51	1.3	24.1	38.7
3	58.1	Adverse	97.1	4842	33	5	34	244	0.0	68.0	70.5
4	67.1	Intermediate	79.1	3138	19	-5	50	-1	7.5	5.1	15.8
5	71.5	Intermediate	89.3	2159	25	4	74	66	3.7	16.5	28.7
6	65.3	Intermediate	88.5	171	35	4	68	15	0.9	3.9	9.8
7	58.5	Not available	91.1	431	36	-2	81	50	1.0	0	0
8	78.0	Intermediate	95.1	54	9	0	-6	12	1.0	10.9	12.5
9	76.4	Intermediate	82.0	363	29	3	196	60	3.6	20.0	18.7
10	68.8	Intermediate	49.3	3316	55	7	114	213	12.5	3.8	7.0
11	73.4	Intermediate	63.2	24	26	-6	7	1	10.5	16.7	8.2
12	83.1	Not available	50.7	1171	26	-33	60	39	6.0	16.7	43.9

Drug-specific cytotoxicity is shown for AMG 330 at a concentration of 50 pg/ml in the presence of healthy donor T-cells at an E/T cell ratio of 1:1.

Abbreviations: AML, acute myeloid leukemia; MFI, median fluorescence intensity.