nomegestrol acetate + estradiol vaginal ring

This investigational drug is a sustained-release vaginal ring formulation combining **nomegestrol acetate (NOMAC)**, a highly selective synthetic progestin, and **17β-estradiol (E2)**, a natural estrogen. Developed by Organon and Co (and previously by Merck & Co. and Schering-Plough), the combination was specifically evaluated for the treatment of **primary dysmenorrhea**. The mechanism of action involves the suppression of the hypothalamic-pituitary-ovarian axis, which inhibits ovulation and reduces the production of prostaglandins in the endometrium, thereby alleviating menstrual pain. While the combination of nomegestrol acetate and estradiol is marketed as an oral contraceptive (brand name Zoely), this specific vaginal ring formulation for primary dysmenorrhea reached Phase 2b clinical trials but did not complete development and was not brought to market.

Other names

nomegestrol acetate/estradiol vaginal ringNOMAC/E2 vaginal ring