Metapristone
Metapristone
Chemical compound
Metapristone (developmental code name RU-42633; also known as desmethylmifepristone) is the major metabolite of mifepristone (RU-486, RU-38486) and a selective progesterone receptor modulator (SPRM) which itself was never marketed.[1][2][3][4] It is formed from mifepristone in the liver by the enzyme CYP3A4 via monodemethylation, and circulates at concentrations higher than those of mifepristone.[1][5] The metabolite retains partial but considerable affinity for the progesterone receptor (PR) and the glucocorticoid receptor (GR) (RBA = 21% and 61% of that of mifepristone for the human forms of these receptors, respectively).[6][1] On the basis of actions that are apparently independent of its hormonal activity, metapristone is being researched as a potential cancer metastatic chemopreventive agent.[2][3][4]