Pharmacokinetic drug evaluation of ulipristal acetate for the treatment of uterine fibroids.

INTRODUCTION: Uterine fibroids are the most common form of benign gynecological tumors in women of reproductive ages. Although surgery is the main option to treat them, alternative pharmacological approaches are being investigated to control their symptoms. Among them, ulipristal acetate (UPA) has been the first selective progesterone-receptor modulator (SPRM) approved for the pre-operative and long-term treatment of uterine fibroids. Areas covered: The aim of this article is to review the literature on the pharmacodynamics, pharmacokinetics (PK), clinical efficacy and safety of UPA for the treatment of uterine fibroids. Expert opinion: UPA has both agonistic and antagonistic activity on progesterone receptor. Results from PK studies have shown that it has good oral bioavailability, and that it is extensively metabolized in the liver by cytochrome (CYP) 3A4. The PEARL I-II showed that the preoperative treatment with UPA decreases uterine bleeding, uterine volume and fibroid size in women with symptomatic uterine leiomyomas. The PEARL III and IV trials demonstrated the efficacy and safety of long-term intermittent treatment with UPA for the control of fibroid-related symptoms.