Ulipristal (acetate) is a novel selective progesterone receptor modulator (SPRM) for the treatment of benign gynecological conditions such as uterine myoma.
Ulipristal acetate blocks activin A modulation of fibronectin and vascular endothelial growth factor A (VEGF-A) mRNA expression in cultured myometrial and leiomyoma cells[2]. Ulipristal acetate decreases the DNA fragmentation at the 100-ng/mL dose and continuing up to the 10,000-ng/mL dose compared to those spermatozoa in the control group[3].
Ulipristal and CDB-4124 have significant antiprogestational activity in vivo[1]. Ulipristal acetate decreases incidences of fibroadenomas and adenocarcinomas in the mammary gland in all treated groups. Ulipristal acetate exposure [AUC(0-24h)] at the highest dose in rats is 67 times human therapeutic exposure at 10 mg/day. In mice, no tumor of any type increases at Ulipristal acetate exposures up to 313 times of therapeutic exposure. Ulipristal acetate-related findings in mice are limited to organ weight changes in the liver, pituitary, thyroid/parathyroid glands, and epididymis as well as minimal panlobular hepatocellular hypertrophy in male and female mice receiving 130 mg/kg/day[4]. Ulipristal acetate (1 mg/kg and 5 mg/kg) increases the frequency with which pathologists assessed the endometrium as being thickened compared to controls in a dose-dependent manner. There is a slight decrease in secretory differentiation with increasing dose of Ulipristal acetate, with small decreases in frequency of sub- and supra-nuclear vacuolation[5].
References:
[1]. Attardi BJ, et al. In vitro antiprogestational/antiglucocorticoid activity and progestin and glucocorticoid receptor binding of the putative metabolites and synthetic derivatives of CDB-2914, CDB-4124, and mifepristone. J Steroid Biochem Mol Biol. 2004 Ma
[2]. Ciarmela P, et al. Ulipristal acetate modulates the expression and functions of activin a in leiomyoma cells. Reprod Sci. 2014 Sep;21(9):1120-5.
[3]. Munuce MJ, et al. Effects of ulipristal acetate on sperm DNA fragmentation during in vitro incubation. Eur J Contracept Reprod Health Care. 2013 Oct;18(5):355-63.
[4]. Pohl O, et al. Carcinogenicity and chronic rodent toxicity of the selective progesterone receptor modulator ulipristal acetate. Curr Drug Saf. 2013 Apr;8(2):77-97.
[5]. Pohl O, et al. A 39-week oral toxicity study of ulipristal acetate in cynomolgus monkeys. Regul Toxicol Pharmacol. 2013 Jun;66(1):6-12.