Background:

IC50: 19 and 117 nM for BRD9 and BRD7, respectively.

BI-7273 is a BRD9 bromodomain inhibitor.

BRD9, a SWI/SNF subunit, is identified to have a key role in leukemia growth, and the BRD9 bromodomain (BD) has been shown to be critical for the proliferation of acute myeloid leukemia cells.

In vitro: BI-7273 was previously demonstrated to mimic genetic perturbation of BRD9. BI-7273 could also target BRD7 BD, a BD protein that was found in a subclass of SWI/SNF remodelling complexes sharing high sequence homology with BRD9. In addition, BI-7273 was able to form an additional positive interaction with the carbonyl of Asn100 in BRD9. Furthermore, BI-7273 showed no measurable activity against BET family BDs even up to a concentration of 100 μM in the biochemical Alpha assay [1].

In vivo: In order to explore the potential of BI-7273 as in-vivo chemical probe, female BomTac:NMRIFoxn1nu mice was orally administered two doses at 20 and 180 mg/ kg and the concentration of BI-7273 in plasma over time was measured. Results showed that dose-dependent but nonlinear AUC was observed for BI-7273, achieving exposure that was higher compared to the EC50 level determined for BI-7273 in proliferation assays with EOL-1 cells [1].

Clinical trial: Up to now, BI-7273 is still in the preclinical development stage.

Reference:
[1] Martin LJ et al.  Structure-Based Design of an in Vivo Active Selective BRD9 Inhibitor. J Med Chem.2016 May 26;59(10):4462-75.