AML xenograft responses to a “4+1” regimen of AraC and DNR in immunodeficient mice. (A) Engraftment levels of AML-1 xenograft cells in the bone marrow (BM) of NOD/SCID mice in response to AraC/DNR dose combinations. 100% represents 50 mg/kg of AraC and 1.25 mg/kg of DNR; 50% (25 mg/kg AraC, 0.63 mg/kg DNR) and 25% (12.5 mg/kg AraC, 0.32 mg/kg DNR) doses were also tested. The mice received three different doses of the AraC/DNR regimen for 2 weeks over days 14–25 after transplantation, and the mice were sacrificed on day 28. Each point represents data from a single mouse; four mice per group. Horizontal bars represent median values. (B) Engraftment levels in blood and respective event-free survival curves for four different AML xenografts treated for 2–3 weeks with AraC (25 mg/kg) and DNR (0.63 mg/kg) in NOD/SCID (AML-17), and NSG (AML-5, 16, and 18) mice. LGD = leukemia growth delay, Horizontal bars underneath the graphs represent time of treatment, each line represents results from an individual mouse (6–15 mice per group). *P<0.05; ***P<0.001; and ****P<0.0001.