Tyrphostin AG1296 is a potent and selective inhibitor of platelet-derived growth factor receptor (PDGFR), with an IC50 of 0.8 μM. Tyrphostin AG1296 inhibits signaling of human PDGF α- and β-receptors as well as of the related stem cell factor receptor (c-Kit). Tyrphostin AG1296 is also a potent inhibitor of FLT3, with an IC50 in the micromolar range.