Metapristone
Metapristone is the major metabolite of mifepristone and a selective progesterone receptor modulator which itself was never marketed. It is formed from mifepristone in the liver by the enzyme CYP3A4 via monodemethylation, and circulates at concentrations higher than those of mifepristone. The metabolite retains partial but considerable affinity for the progesterone receptor and the glucocorticoid receptor . On the basis of actions that are apparently independent of its hormonal activity, metapristone is being researched as a potential cancer metastatic chemopreventive agent.
