EP prolongs survival in mouse models of leukemia. (A) Ten million HL60 cells were transplanted into the tail veins of NSG mice (n = 10) 4 hours after sublethal irradiation. Mice were divided into 2 groups, one receiving untreated drinking water, and the other receiving 1 mg/mL of EP in the drinking water starting at day +3. BM aspirates were performed on day +21 and FACS analysis was performed assessing donor cell chimerism (CD15⁺Ly5.1⁻; i). Kaplan Meier survival curve of HL60-transplanted mice (ii) treated with 1 mg/mL or 3.0 mg/mL EP in the drinking water versus mice with untreated drinking water. *P < .05; **P < .01. (B) One million URE cells were transplanted into the tail veins of NSG mice 4 hours after sublethal irradiation. Mice were divided into 3 groups, with one group receiving untreated drinking water (n = 7), one group receiving 0.4 mg/mL of EP in the drinking water (n = 5), and the other receiving 1 mg/mL of EP in the drinking water (n = 4) starting at day +3. Kaplan-Meier survival curve of URE transplanted mice treated with 0.4 or 1.0 mg/mL of EP in the drinking water versus mice with untreated drinking water is shown. **P < .01. (C) HL60 cells were treated with or without 20nM cytarabine (i), with or without 24 ng/mL of doxorubicin (ii) ± 5 μg/mL of EP for 72 hours. Cell viability was measured by cell counts with trypan blue exclusion. Data represent the means ± SD of viable cells performed in triplicate. **P < .01; ***P < .001.