Efficacy and safety of vilaprisan in women with uterine fibroids: data from the ASTEROID 3 randomized controlled trial

Objective

Vilaprisan is a highly potent selective progesterone receptor modulator shown to reduce heavy menstrual bleeding, induce amenorrhea, and diminish uterine fibroid volume in phase 2 studies. The objective of ASTEROID 3 was to demonstrate the superiority of vilaprisan compared with placebo in the treatment of heavy menstrual bleeding in women with uterine fibroids.

Design

Randomized, double-blind, placebo-controlled, multicenter phase 3 study.

Setting

Hospitals and medical centers.

Patient(s)

Women with ≥1 uterine fibroid of ≥3 cm and heavy menstrual bleeding of >80 mL/cycle.

Intervention(s)

Women were randomly assigned to 1 of 4 treatment arms, which were planned to comprise 2 treatment periods of 12 weeks, each with vilaprisan (2 mg/d) or placebo that were continuous or separated by a break of one bleed.

Main Outcome Measure(s)

Amenorrhea (primary end point; <2 mL in the last 28 days of treatment) and heavy menstrual bleeding response (key secondary end point; <80 mL/cycle and >50% reduction in bleeding from baseline) were measured with the alkaline hematin method. Change in volume of the 3 largest fibroids from baseline to end of treatment was assessed by ultrasound. Safety was monitored throughout the study.

Result(s)

Overall, 75 women completed the first 12 weeks of treatment. Statistically significant and clinically meaningful differences were observed between the vilaprisan- and placebo-treated groups in both the full analysis and per-protocol sets. In the per-protocol set (n = 36 and n = 12 for the vilaprisan and placebo groups, respectively), amenorrhea was observed more frequently in women treated with vilaprisan than in those who received placebo (83.3% vs. 0%, P<.0001), with a median time to onset of 3 days in the vilaprisan group. Similarly, more vilaprisan- than placebo-treated women achieved a response in heavy menstrual bleeding (91.7% vs. 25.0%, P<.0001). Serious adverse events were reported for 22 (27.8%) of 79 women and were evenly distributed among the 4 groups receiving vilaprisan and/or placebo. None of these events led to study discontinuation or were related to the liver, and no new safety findings were identified compared with the earlier phase 2 ASTEROID studies.

Conclusion(s)

Vilaprisan is efficacious and well tolerated over 12 weeks in the treatment of heavy menstrual bleeding associated with uterine fibroids. Further investigations of the long-term efficacy and safety of vilaprisan are warranted.

Clinical Trial Registration Number

NCT03400943 (ClinicalTrials.gov).