Mivebresib (ABBV-075) is a novel BET family bromodomain inhibitor. It binds bromodomains of BRD2/4/T with similar affinities (Ki of 1-2.2 nM) and highly selective for 18 bromodomain proteins tested (Kd > 1 μM; more than 600-fold selectivity vs. BRD4), but exhibits roughly 10-fold weaker potency towards BRD3 (Ki of 12.2 nM) and has moderate activity towards CREBBP (Kd = 87 μM; 54-fold selectivity vs. BRD4). Mivebresib(ABBV-075) efficiently triggers apoptosis in various tumor cell.