Figure 4.

Binding modes of FLT3 inhibitors to FLT3 molecule. Schematic diagrams of FLT3 kinase inhibition are shown. FLT3 inhibitors are classified into Type I and Type II inhibitors according to the mode of binding to FLT3. The Type I inhibitors bind to only the ATP‐binding site, enabling binding to both active and inactive conformations of FLT3. In contrast, because the type II inhibitors are designed to favorably bind to the back pocket of the inactive conformation of FLT3 to increase the affinity for the ATP‐binding site, they can bind to only the inactive conformation. FF‐10101 is designed to form a covalent binding between the C695 residue of FLT3. This covalent bond formation of FF‐10101 maintains the ability to bind to both the active and inactive conformations of FLT3