In treated cancer cells (e.g., MV-4-11 leukemia, H929 multiple myeloma):

EZD-349 reversibly binds the ATP-binding pocket of CDK9 with an apparent . At 100 nM, it inhibits >90% of CDK9 kinase activity in cell-free assays. It shows no significant inhibition of CDK1 (IC50 >1.5 µM) or CDK2 (IC50 >2.0 µM).