DDO-2213 is a potent, orally active inhibitor of the WDR5-MLL1 interaction, demonstrating an IC50 of 29 nM and a Kd of 72.9 nM against WDR5. It selectively inhibits MLL (mixed lineage leukemia) histone methyltransferase activity, and suppresses the proliferation of cells harboring MLL translocations, positioning it as a valuable tool for MLL fusion leukemia research [1].