In vivo effect of BC8 on GO-induced cytotoxicity in mice bearing human AML xenografts. (A) Tumor volumes. Athymic mice bearing HL-60 xenografts were randomized and either left untreated (●) or injected intraperitoneally with BC8 (10 μg, ■) on a 5 days on/2 days off schedule for 5 cycles, GO (5 μg, ▴) on days +1, +5, +9, +22, +26, and +30, or BC8 (10 μg) combined with GO (5 μg) (▾) administered on an identical schedule as in the individual treatment group. Tumors were measured in 3 dimensions with calipers 3 times per week. Tumor volumes of dead mice were maintained in the curve until the last mouse of the corresponding group was killed. Results are shown as mean plus or minus SEM. CR denotes complete resolution of measurable tumor. *P < .05 compared with treatment with BC8 alone. (B) Survival. Groups of 10 mice bearing HL-60 tumor xenografts were either left untreated (●) or injected intraperitoneally with BC8 (10 μg, ■), GO (5 μg, ▴), or a combined therapy of BC8 (10 μg) and GO (5 μg) (▾) as described for panel A, and analyzed for survival as a function of time. Proportions of surviving animals in each treatment group are shown. Mice were killed if the tumors caused discomfort, impaired ambulation, or weight loss of more than 30% of starting weight. Four of 10 animals survived after combined therapy with BC8 and GO, whereas none of the animals treated with either BC8 or GO survived (P = .008; Fisher exact test); similarly, all untreated animals died.