Birabresib 是一种BRD2/3/4抑制剂，IC50值为 92 到 112 nM之间，具有潜在的抗肿瘤活性。

Birabresib is a synthetic, small molecule inhibitor of the BET (Bromodomain and Extra-Terminal) family of bromodomain-containing proteins 2, 3 and 4 with potential antineoplastic activity.

OTX015 inhibits the binding of BRD2, BRD3, and BRD4 to AcH4 with IC50 ranging from 92 to 112 nM, and inhibits the growth of a variety of human cancer cell lines with GI50 ranging from 60 to 200 nM. [1] OTX015 results in rapid down-regulation of c-MYC expression, and show the synergistic anti-proliferative effects in combination with ALK inhibitors in ALKpos ALCL cell lines. [2]

OTX015 (p.o.) significantly inhibits the growth of Ty82 BRD-NUT midline carcinoma tumors in nude mice by 79% at 100 mg/kg qd and 61% at 10 mg/kg bid, respectively. [1]

TR-FRET Assay[1]: To assess binding of OTX015 to BRD2, BRD3, and BRD4, BRD-expressing CHO cell lysate (from CHO cells transfected with expression plasmids for Flag-tagged BRD2, BRD3, or BRD4 or vector alone), europium-conjugated anti-Flag antibody, XL-665-conjugated streptavidin, and biotinylated OTX015 are incubated at room temperature for 0.2 to 2 h. Fluorescence is measured by TR-FRET using an EnVision 2103 Multilabel Reader and EC50 for binding is calculated by nonlinear regression using PRISM version 5.02.