Progesterone receptor antagonist (PRAs) and progesterone receptor selective modulators (SPRMs): Applications in gynaecology and obstetrics

Abstract

Biochemical, pharmacological and clinical studies have led to synthesizing progesterone receptor antagonists (PRAs) and selective progesterone receptor modulators (SPRMs) during the last two decades. The progesterone receptor (PR) shares its structure with that of other steroid receptors which undergo a conformational change after being stimulated and consequently activate genetic transcription in specific tissues. This process depends (particularly in the PA) on the balance between previously identified co-activators and co-repressors. Mifepristone has been catalogued as being PRA whilst asoprisnil is the classical SPRM agonist-antagonist. Multiple experimental and clinical trials have shown the real usefulness of PRAs and SPRMs in everyday clinical scenarios such as uterine myomatosis, endometriosis, termination of pregnancy and contraception. Nevertheless, there is no ideal SPRM and studies supporting the safety and efficacy of mifepristone and asoprisnil are still lacking. This article was aimed at reviewing the pharmacodynamic and clinic uses of these medications in obstetrics and gynaecology.