CPI-169 (racemate）

Biological Activity

CPI-169 racemate is the racemate form of CPI-169, which is a novel and potent EZH2 inhibitor with IC50 <1 nM(inhibition of the catalytic activity of PRC2); decreases cellular levels of H3K27me3 with an EC50 of 70 nM, and triggers cell cycle arrest and apoptosis in a variety of cell lines. IC50 value: < 1 nM (catalytic activity of PRC2); 70 nM (Cellular EC50) in vitro: CPI-169, a representative compound from that effort, inhibits the catalytic activity of PRC2 with an IC50 of < 1nM, decreases cellular levels of H3K27me3 with an EC50 of 70 nM, and triggers cell cycle arrest and apoptosis in a variety of cell lines. Importantly, compound treatment triggers a sequence of downstream functional consequences of EZH2 inhibition whereby apoptosis is not induced before ten days of continuous target engagement . in vivo: Administered subcutaneously at 200 mpk twice daily (BID), CPI-169 is well tolerated in mice with no observed toxic effect or body weight loss. In the present study we show that CPI-169 treatment led to tumor growth inhibition (TGI) of an EZH2 mutant KARPAS-422 DLBCL xenograft. The TGI is proportional to the dose administered and to the reduction of the pharmacodynamic marker H3K27me3. The highest dose, 200 mpk, BID led to complete tumor regression. Since CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) is the standard treatment of advanced DLBCL, we were interested in combining a suboptimal dose of CPI-169 (100 mpk, BID) with a single dose of CHOP in the KARPAS-422 model. After a week of combinatorial treatment the tumors rapidly regressed and became unpalpable. Four weeks after the last dose only a single mouse presented a palpable tumor.

Published experimental findings depend on the model and assay conditions. They do not guarantee equivalent performance in every application. For laboratory research use only.