Ulipristal acetate for Japanese women with symptomatic uterine fibroids: A double‐blind, randomized, phase II dose‐finding study

PURPOSE: A multicenter, randomized, double‐blind, placebo‐controlled trial was conducted to evaluate the efficacy, safety, and appropriate dose of ulipristal acetate (UPA) in Japanese women with symptomatic uterine fibroids (UFs). METHODS: A total of 121 premenopausal women with UFs were enrolled to receive either placebo, UPA‐2.5 mg, UPA‐5 mg, UPA‐10 mg, or leuprorelin acetate (LEU), a reference drug, for 12 weeks. The primary end point was the rate of patients having achieved amenorrhea for 35 days at Week 12. RESULTS: The rates for amenorrhea were 4.5%, 60.0%, 72.7%, 88.0%, and 76.2% in the placebo, UPA‐2.5 mg, UPA‐5 mg, UPA‐10 mg, and LEU groups, respectively. The median times to amenorrhea were 20.0, 5.0, 5.0, and 23.0 days for treatment with UPA‐2.5 mg, UPA‐5 mg, UPA‐10 mg, and LEU, respectively. A significant dose‐response of UPA for the rate of amenorrhea was observed. The overall incidence rates of adverse events were 45.8% in the placebo group, 56.5%‐80.0% in the UPA groups, and 100.0% in the LEU group. There were no notable safety issues with UPA. CONCLUSIONS: Ulipristal acetate was effective and well tolerated in Japanese women with UFs. The recommended dose of UPA is considered to be 10 mg.