BET BD2-IN-1 (compound 45) is a potent and selective inhibitor of BET BD2 ( IC 50 =1.6 nM). BET BD2-IN-1 inhibits the differentiation of Th17 cells by decreasing the activation of STAT3 and NF-κB. BET BD2-IN-1 is used in psoriasis and inflammatory bowel disease (IBD) research.