BET bromodomain inhibitor; blocks recruitment of BET to chromatin. Induces apoptosis and G0/G1 cell cycle arrest in MLL-fusion leukemic cell lines in vitro (IC50 values are 15, 26, 120 and 192 nM for NOMO1, MV4;11, MOLM13 and RS4;11 cell lines respectively); reduces BCL2 expression in NOMO1 cells. Improves survival in two rodent models of MLL-fusion leukemia in vivo. Enhances differentiation of human iPSC into megakaryocytes. Purity 98%. MW (observed): 488.37