OTX015 is a potent inhibitor of BRD2, BRD3, and BRD4 (EC₅₀s = 10-19 nM). It displays antiproliferative effects at a sub-micromolar range in vitro in a wide range of solid tumor types and leukemias, downregulating c-Myc expression and inducing cell cycle arrest and apoptosis. At 100 mg/kg, OTX015 has been shown to inhibit the growth of Ty82 BRD-NUT midline carcinoma tumors in nude mice by 79%.