PLX647 was tested against a panel of 400 kinases at a concentration of 1 μM, 35-fold above its FMS enzymatic IC50 and 60-fold above its KIT enzymatic IC50. In addition to FMS and
KIT, the activities of only nine kinases were inhibited by more than 50%. PLX647 potently inhibits the growth of FLT3–ITD-expressing MV4-11 cells (IC50 = 0.11 μM) but not OCI-AML5 (IC50 = 1.6 μM),
which express wild-type FLT3.