HDAC-IN-63 (Compound 63) is a dual FLT3/HDAC inhibitor with IC50 values of 0.844 nM for FLT3 and 30.0 nM for HDAC1. It effectively suppresses MV4-11 cell proliferation (IC50 of 92 nM), induces apoptosis, and arrests the cell cycle in MV4-11 cells. This compound is applied in acute myeloid leukemia (AML) research [1].