BCT-100 arginine depletion reduces the number of viable AML blasts in vitro and in vivo. (A) Plasma from control and BCT-100 treated NOG mice were collected after 14 days. The concentration of arginine was determined by ELISA. BCT-100 significantly lowers the plasma arginine concentration in vivo (P < .0244). (B) NOG mice were injected with HL-60 AML blasts. BCT-100 (5 mg/kg) or cytarabine (25 mg/kg) was given i.p. injections twice a week. Bone marrow was sampled from the femurs after 5 weeks to assess hCD45⁺ cells by flow cytometry. BCT-100 leads to significantly lower AML engraftment (P = .029), equivalent to cytarabine treatment. Data are representative of 2 independent experiments. (C) Untreated and BCT-100 NOG mice engrafted with HL-60 AML showed no significant difference in body weight in response to treatment.