Nonsteroidal progesterone receptor modulators: structure activity relationships

Progesterone, acting primarily via the progesterone receptor (PR), plays an essential role in the regulation of female reproduction. Steroidal progestins (i.e., PR agonists) are commonly used in women's health, such as in contraception and hormone therapy and for the treatment of gynecological disorders. Recent studies in women and in nonhuman primates also indicate that PR antagonists may have potential applications in contraception and for the treatment of reproductive disorders such as fibroids and endometriosis. Currently, all clinically available PR agonists and antagonists are steroidal compounds. They often cause various side effects due to their functional interactions with other steroid receptors or because of effects associated with their steroidal metabolites. In an effort to identify more receptor-selective and structurally diverse compounds that may render clinical advantages over steroidal PR ligands, numerous receptor-selective novel nonsteroidal PR agonists and antagonists have been discovered. This review focuses on the structure activity relationships and the biological profile of the nonsteroidal PR modulators discovered in the last decade.