The PLK1 inhibitor volasertib delays development of poor outcome human AML in a xenotransplantation mouse model. (A) Summary of the treatment protocols and time point analysis for NSG mice transplanted with 0.2 million HL-60 leukemic cells or 2 million 09H046 AML cells. Six days after transplantation, mice were treated with either volasertib (IV, 2 times a week for 4 weeks at 10 mg/kg) or cytarabine (intraperitoneally for 5 consecutive days at 50 mg/kg). Vehicle-treated mice received both phosphate-buffered saline (intraperitoneally) and 0.9% NaCl (IV). BM aspirations were performed at days 16 and 37 in 09H046-transplanted mice only. (B) Kaplan-Meier curves as determined for vehicle-, cytarabine-, and volasertib-treated mice transplanted with HL-60 cells. Log-rank test was used to evaluate the statistical significance. Representative flow cytometry profiles of BM cells at day 16 (C) and day 37 (E) in vehicle-, cytarabine-, and volasertib-treated mice transplanted with 09H046 AML cells. (D,F) report the percentage of human CD45⁺ cells in BM at days 16 and 37 in all treated mice transplanted with 09H046 AML cells. Medians are represented by a black line in dot plots. SSC-A, side scatter area.