Potent inhibition of G-749 against patient blasts harboring FLT3-ITD or FLT3-D835Y. (A) AML patient blasts expressing FLT3-WT (patient 3), FLT3-ITD (patients 11 and 12), FLT3-D835Y (patients 13 and 14), or FLT3-ITD/D835Y (patient 16) were incubated for 72 hours with the indicated concentrations of G-749, AC220, or PKC412, and their viability was then determined. For each FLT3 inhibitor, the percentage over DMSO control was presented as a mean value, with error bars representing ±SD. (B) Inhibition of the FLT3 signal pathway. The blasts harboring FLT3-ITD (patients 11 and 12) or FLT3-D835Y (patients 13 and 14) were incubated with 100 nM of FLT3 inhibitors for 2 hours (in the case of patient 12, with 250 nM), and then the phosphorylation levels of FLT3, STAT5, AKT, and ERK1/2 were analyzed. Each total protein was used as a loading control.