Vilaprisan in women with uterine fibroids: the randomized phase 2b ASTEROID 1 study

OBJECTIVES: To assess the safety and efficacy of four vilaprisan doses (0.5-4.0 mg) in women with uterine fibroids. DESIGN: Randomized, double-blind, placebo-controlled, multicenter trial. SETTING: Ninety-eight centers in 12 countries. PATIENT(S): Women aged 18-50 years with uterine fibroids and heavy menstrual bleeding were randomized equally to oral vilaprisan at 0.5, 1.0, 2.0, or 4.0 mg or placebo once daily. INTERVENTION(S): Treatment for 12 weeks, 24-week follow-up. MAIN OUTCOME MEASURE(S): Primary end point was absence of scheduled or unscheduled bleeding/spotting. Key secondary efficacy end points included volume of menstrual blood loss and change in fibroid volume. RESULT(S): A total of 309 patients were randomized, and 300 received treatment. Complete absence of bleeding/spotting was observed in 30%, 56%, 54%, and 60% of patients in the vilaprisan 0.5, 1.0, 2.0, and 4.0 mg groups, respectively, versus 1.7% with placebo. After 12 weeks, >83% of women achieved amenorrhea (<2 mL/28 days) with ≥1.0 mg vilaprisan versus 9% with placebo. Heavy menstrual bleeding stopped (but returned at a lower volume after treatment cessation) with ≥1.0 mg vilaprisan treatment. Reductions in fibroid volume of up to 41% were observed. Most patients receiving vilaprisan reported improvements in symptom severity. No safety concerns were identified in general safety, endometrial safety (by biopsy), laboratory values, and ultrasound examinations. CONCLUSION(S): ASTEROID 1 supports the efficacy of vilaprisan for the treatment of heavy menstrual bleeding associated with uterine fibroids. Daily oral treatment with vilaprisan 0.5-4.0 mg was well tolerated, and vilaprisan 2.0 mg once daily has been selected for further investigation. CLINICAL TRIAL REGISTRATION NUMBER: NCT02131662.