Information Brilanestrant (GDC-0810, ARN-810） is a potentER-αbinder (ER-α, IC50 = 6.1 nM; ER-β, IC50 = 8.8 nM), a full transcriptional antagonist with no agonism and displays good potency and efficacy in ER-α degradation (EC50 = 0.7 nM) and MCF-7 breast cancer cell viability (IC50 = 2.5 nM) assays with good selectivity over other nuclear hormone receptors. Targets ERα (Cell-free); ERβ (Cell-free) 6.1 nM; 8.8 nM In vitro In cell-free radio-ligand competitive binding assays, GDC-0810 binds both ERα and ERβ with low nanomolar affinity. GDC-0810 has little to no inhibition against CYP1A2, CYP2D6, or CYP3A4 (IC50 > 20 μM), modest inhibitory effect on CYP2C9 and CYP2C19 (IC50 = 2.2 and 3.3 μM respectively), and potent inhibition of CYP2C8 (IC50 of 1 μM). While in binding assays, GDC-0810 displays little activity toward the androgen receptor (AR; IC50 > 4 μM) and GR (IC50 = 0.99 μM). GDC-0810-mediated ERα depletion is dependent on the 26S proteasome. GDC-0810 antagonizes ERα ligand binding domain mutants in vitro and in vivo. In cell-free E2 competitive binding assays that was used to determine the binding of GDC-0810 to ER.WT, ER.Y537S and ER.D538G ligand binding domains, GDC-0810 retains its ability to potently displace E2 from the ligand binding domain, albeit with a slightly increased IC50 (WT: 2.6 nM vs. ER.Y537S: 5.5 nM and ER.D538G: 5.4 nM). GDC-0810 can compete the PGC1α co-activator peptide off the mutated ligand binding domain, implying that GDC-0810 is capable of driving an \'active\' to \'inactive\' conformational shift of mutant ER, though with a ~five-seven fold reduction in biochemical potency compared to wild-type ER. In vivo The pharmacokinetic profile of GDC-0810 shows it is a low clearance molecule across species, with good bioavailability (40−60%). As would be expected for a lipophilic carboxylic acid, the compound is highly bound to plasma proteins (>99.5% across species) and has a low to moderate volume of distribution (Vss = 0.2−2.0 L/kg across species). GDC-0810 exhibits good bioavailability across species and displays robust activity in tamoxifen-sensitive and tamoxifen-resistant xenograft models of breast cancer. GDC-0810 displays mild estrogenic activity in uterine models in vitro and in vivo. Cell Research(from reference) Cell lines：MCF-7 cells Incubation Time：4 h