Selective inhibition of MLL-rearranged cell proliferation by EPZ-5676. (A) Inhibition of the proliferation of MV4-11 cells following 14-day treatment with the indicated concentrations of EPZ-5676 (n = 3, mean ± SD are shown). (B) Effect of treatment of MV4-11 cells with 1 μM EPZ-5676 on cell-cycle phase and apoptosis over time as measured by staining for DNA content and Annexin V. (C) EPZ-5676 selectively kills acute leukemia cell lines harboring MLL fusions. IC₅₀ values for inhibition of proliferation are plotted for each cell line following 14 days of exposure to increasing concentrations of EPZ-5676 (n = 2, mean value is shown, apart from MV4-11, where n = 3). Cell lines are grouped according to MLL status and horizontal lines represent the mean IC₅₀ value for each group. IC₅₀ values are also listed along with IC₉₀ values in supplemental Table 2.