Pharmacokinetic evaluation of ulipristal acetate for uterine leiomyoma treatment.

INTRODUCTION: Progesterone (P), and its receptors (PRs), play a key role in uterine leiomyoma growth. Selective progesterone receptor modulators exert mixed antagonist and agonist effects on the PRs. Mifepristone, a PR-antagonist, reduces leiomyoma volume and related symptoms. Ulipristal acetate (UPA) exerts a potent antiprogestin activity, with less antiglucocorticoid activity compared to mifepristone. This property provides potential advantages for long-term use. AREAS COVERED: This paper focuses on the effect of UPA on leiomyoma's growth and related symptoms in women. The authors also evaluate UPA's efficacy in reducing leiomyoma's size and menorrhagia in Phase II/III trials. EXPERT OPINION: In the authors' opinion, UPA (5 mg/day) over 3 months can be used to plan the surgery in women with symptomatic leiomyomas. The tolerability and the safety of treatment over a period longer than 3 months have to be evaluated. The results of the follow-up treatment suggest that further studies could successfully evaluate the efficacy and the tolerability of intermittent 3-month courses of treatment.