(A and B) Primary AML patient samples were cultured in methylcellulose medium with the indicated concentrations of MRX-2843 or vehicle (DMSO). Colonies were stained and counted after 10 days. Each sample was plated in triplicate, and mean values and standard errors are shown. (C) Human cord blood collected from healthy donors was cultured in methylcellulose, and colonies were counted as above. Mean values and standard errors were derived from 3 independent experiments and are relative to vehicle-treated controls. **P < 0.01 and ***P < 0.001, by 1-way ANOVA. AML, acute myeloid leukemia; FLT3, FMS-like tyrosine kinase 3; ITD, internal tandem duplication.