DDO-2213 is an orally active and potent WDR5-MLL1 inhibitor, with an IC 50 of 29 nM and a K d value of 72.9 nM for the WDR5 protein. DDO-2213 selectively inhibits MLL (mixed lineage leukemia) histone methyltransferase activity and the proliferation of MLL translocation-harboring cells. DDO-2213 can be used for MLL fusion leukemia research.