In vitro cytotoxic effects of lestaurtinib and PKC412 in combination with cytarabine. (A) Dot plot showing the range of individual patient combination indices (CIs) obtained following analysis of MTS in vitro cytotoxicity assay fixed-ratio drug combination data using the method of Chou and Talalay. Median and quartiles are shown for each drug combination. P values refer to the significance of a postulated synergistic population effect for each drug combination and were obtained using the V² test to assess the distribution of the study population relative to an equally sized hypothetical population with a median CI of 1. (B) Dot plots showing the range of individual patient CIs obtained following in vitro treatment with lestaurtinib/AraC and PKC412/AraC. Patients are grouped according to FLT3 mutation status, and P values again refer to V² test used to assess for significance of synergistic effects.