BRD4-BD1 2-IN-1 is a highly effective inhibitor of BRD4, specifically targeting the BRD4 BD-1 and BRD4 BD-2 domains with IC 50 values of <100 nM each (US20150148375A1, compound 5) [1].
dBRD4-BD1 is a selective BRD4 bromodomain inhibitor. dBRD4-BD1 can selectively degrade BRD4 (DC50 = 280 nM). Notably, dBRD4-BD1 upregulates BRD2 3, a result not observed with degraders using pan-BET ligands. Designing BRD4 selectivity up front enables analysis of BRD4 biology without wider BET-inhibition and simplifies designing BRD4-selective heterobifunctional molecules, such as degraders with new E3 recruiting ligands or for additional probes beyond degraders.