In Vitro: Ulipristal acetate (0.1-5 μM; 96 hours) stimulates autophagy in leiomyoma cells. Ulipristal-induced expression changes of the autophagic markers LC3 and p62/SQSTM1. Ulipristal up-regulates Atg7 protein in leiomyoma cells. Ulipristal acetate blocks activin A modulation of fibronectin and vascular endothelial growth factor A (VEGF-A) mRNA expression in cultured myometrial and leiomyoma cells.
In Vivo: Ulipristal and CDB-4124 have significant antiprogestational activity in vivo. 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. 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.