In vitro study | The binding capacity of AZD9496 to the two subtypes of ERα and ERβ is equal, both in the pmol range. AZD9496 can directly target ER alpha and down regulate ER alpha in vitro. In in vitro and in vivo experiments, AZD9496 was able to antagonize and down-regulate the ER mutant. The binding, downregulation and antagonism IC50 of AZD9496 to ERα were 0.82, 0.14 and 0.28 nM, respectively. |
In vivo study | AZD9496 has high oral bioavailability in a variety of animals (63%, 91% and 74% in rats, mice and dogs, respectively), the blood volume and clearance rate were lower (clearance rate was higher in mice). The free concentration of AZD9496 in human plasma is 0.15%, which is 5 times that of fulvestrant. AZD9496 is a potent, oral inhibitor of breast tumor growth in vivo. In the ER + animal model of drug-resistant estrogen deprivation, AZD9496 was used in combination with the PI3K pathway, a CDK4/6 inhibitor, leading to tumor regression while causing a dose-dependent decrease in PR protein. AZD9496 is currently in Phase I clinical trial. |