Background:

IC50: 0.03 and 11.0 μM for CBP/EP300 and BRD4, respectively.

CPI-637 is a CBP/EP300 bromodomain inhibitor.

It has been reported that among bromodomain-containing proteins implicated in various disease pathways, cyclic-AMP response element binding protein (CBP) and adenoviral E1A binding protein of 300 kDa (EP300), which is a highly homologous pair of bromodomain-containing transcriptional coactivators, are of great interest as potential drug targets due to their reported involvement in a variety of disease states.

In vitro: Previous study found that CPI-637 was potent against EP300, and its opposite enantiomer showed a over 200-fold loss in potency. Moreover, the biochemical potency of CPI-637 translated well into cells with CBP BRET EC50 of 0.3 μM, and CPI-637 demonstrated a more than 700-fold selectivity over the BET family of bromodomains. In addition, CPI-637 was also highly selective against other bromodomains, showing substantial biochemical activity only against BRD9. Furthermore, it was found that CPI-637 was able to inhibit the expression of MYC with an EC50 of 0.60 μM in a cellular assay,. [1].

In vivo: So far, there is no animal in vivo data reported.

Clinical trial: Up to now, CPI-637 is still in the preclinical development stage.

Reference:
[1] Taylor, A.  M. et al. Fragment-Based Discovery of a Selective and Cell-Active Benzodiazepinone CBP/EP300 Bromodomain Inhibitor (CPI-637). ACS medicinal chemistry letters 7, 531-536, doi:10.1021/acsmedchemlett.6b00075 (2016).