A potent and specific Aurora kinase B inhibitor. It is 1000-fold more selective for aurora kinase B than for aurora kinase A ( Ki values of 1300 nM and 0.36 nM for aurora kinase A and B, respectively). At concentrations as low as 0.01 µM, AZD 1152 produced a significant (p<0.05) decrease in the ability of NB4 cells to proliferate by 48 hours.