OTX015 is a novel, highly potent, selective and cell permeable inhibitor of the bromodomain and extra terminal (BET) family proteins BRD2, BRD3 and BRD4 with IC50 of 10-19 nM. It inhibits the growth of a variety of human cancer cell lines with IC50 ranging from 60 to 200 nM. OTX015 results in rapid down-regulation