Description
H3B-6545 is an oral, selective estrogen receptor covalent antagonist ( SERCA ) for the research of metastatic ER-positive, HER2-negative breast cancerIn VitroH3B-6545 is a highly selective small molecule that potently antagonizes wild-type and mutant ERα in biochemical and cell based assays. In vitro comparisons with standard of care and other experimental agents confirm increased cell potency of H3B-6545 under continuous as well as washout treatment conditions. H3B-6545, a member of a novel class of ERα antagonists refer to as selective ER covalent antagonist (SERCA), which inactivates both wild-type and mutant ERα by targeting C530 and enforcing a unique antagonist conformation. H3B-6545 is a first-in-class selective ER covalent antagonist (SERCA). H3B-6545 inhibits ERα WT activity and growth of ERα WT -positive breast cancer lines. H3B-6545 potently inhibits ERα WT activity and suppresses proliferation of ERα WT -positive breast cancer lines. With GI 50 s of 0.3-0.4, 1.0, 0.5, 5.2, and 0.2 nM for MCF7, HCC1428, BT483, T47D and CAMA-1 cell lines. MCE has not independently confirmed the accuracy of these methods. They are for reference only.In VivoIn vivo, once daily oral dosing of H3B-6545 shows potent activity and superior efficacy to fulvestrant in the MCF-7 xenograft model with maximal antitumor activity at doses >10x below the maximum tolerated dose in mice. In addition, H3B-6545 shows superior antitumor activity to Tamoxifen and Fulvestrant in patient derived xenograft models of estrogen receptor positive breast cancer including models carrying ERα mutations in rat and monkeys, H3B-6545 is well tolerated across a broad dose range and at exposures that significantly exceed those required for efficacy in mouse xenograft models. MCE has not independently confirmed the accuracy of these methods. They are for reference only.IC50& Target:Estrogen receptor