asoprisnil

Asoprisnil is a synthetic, steroidal selective progesterone receptor modulator (SPRM) with mixed agonist–antagonist activity at the progesterone receptor. It was developed for the treatment of uterine fibroids and other progesterone-sensitive conditions. Asoprisnil binds to the progesterone receptor with higher affinity than natural progesterone and exerts tissue-selective effects by acting as both an agonist and antagonist depending on cellular context. In clinical studies, it effectively reduced menstrual bleeding and decreased fibroid volume without inducing significant hypoestrogenic symptoms. Mechanistically, it suppresses collagen synthesis in leiomyomas (fibroids), induces apoptosis in these cells while sparing normal myometrium, decreases antiapoptotic Bcl-2 expression, increases caspase-3 activity, reduces vascular endothelial growth factor (VEGF), and lowers proliferating cell nuclear antigen (PCNA) levels. However, its development was discontinued after phase III trials due to concerns about endometrial safety—specifically abnormal endometrial changes observed during long-term use[1][5][6][7].

Other names

asoprisnilum