Ulipristal acetate - safety and pharmacokinetics following multiple doses of 10-50mg per day

What is known and Objective: Ulipristal acetate (UPA) is a novel selective progesterone receptor modulator for benign gynaecological conditions such as uterine myoma. The safety and pharmacokinetics of multiple-dose UPA and its N-mono-demethylated metabolite, PGL4002, were investigated in women. Methods: The double-blind, placebo-controlled study randomized 32 healthy women of reproductive age to receive 10 consecutive daily doses of placebo, 10, 20 or 50 mg UPA. Safety assessments included vital signs, physical examination, ECG, clinical laboratory tests and reporting of adverse events. Blood samples for pharmacokinetic analysis were collected on Days 1 and 10 at intervals until 168 h after multiple dosing. Results: UPA was well tolerated at all doses. Mild or moderate adverse events occurred with similar frequency in UPA and placebo groups. UPA median t(max) was 075 and 089h, and mean plasma half-life was between 38 and 49h. C-max values (Day 1) were 422, 1309 and 3548ng/mL for the UPA 10, 20 and 50mg treatment groups, respectively. Corresponding C-max values for Day 10 were 637, 1698 and 4549ng/mL. AUC(SS) values on Day 10 were 2166, 6028 and 16557ngh/mL after 10, 20 and 50mg UPA, respectively. For the principal metabolite PGL4002, t(max) and plasma elimination half-life values were similar to those of UPA. PGL4002 AUC(SS) Day 10 values were 847, 2036 and 4521ngh/mL for 10, 20 and 50mg groups, respectively. What is new and Conclusion: Daily administration of UPA at therapeutic and supratherapeutic doses was well tolerated by women of reproductive age. UPA exposure increases with dose. Exposure to PGL4002 is approximately one-third that of UPA.