• Yutaka Osuga, Kazuaki Enya, Kentarou Kudou, Masataka Tanimoto, and Hiroshi Hoshiai.
• Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan; and Takeda Pharmaceutical Company Limited, and Kindai University, Osaka, Japan.
• Obstet Gynecol. 2019 Mar 1; 133 (3): 423-433.

ObjectiveTo investigate the noninferiority of relugolix compared with leuprorelin acetate in reducing heavy menstrual bleeding associated with uterine leiomyomas.MethodsIn a double-blind, double-dummy trial, premenopausal women with uterine leiomyomas and heavy menstrual bleeding defined as a pictorial blood loss assessment chart score of at least 120 were randomized in a 1:1 ratio to relugolix (40 mg, oral, once daily) or leuprorelin acetate (1.88 mg or 3.75 mg, monthly injection) for 24 weeks. The primary endpoint was the proportion of patients with a total pictorial blood loss assessment chart score of less than 10 for weeks 6-12. Secondary endpoints included myoma and uterine volumes, and hemoglobin levels. A sample size of 144 patients per group (n=288) was estimated to provide at least 90% power to demonstrate noninferiority (prespecified noninferiority margin -15%; one-sided 0.025 level of significance).ResultsFrom March 2016 to September 2017, 281 patients were randomized (relugolix, n=139, leuprorelin n=142). Demographic and baseline characteristics were well balanced; mean pictorial blood loss assessment chart score was 254.3 in the relugolix group and 263.7 in the leuprorelin group. The proportion of patients with total pictorial blood loss assessment chart score of less than 10 for weeks 6-12 was 82.2% in the relugolix group and 83.1% in the leuprorelin group, demonstrating noninferiority of relugolix compared with leuprorelin (relugolix-leuprorelin difference -0.9%; 95% CI: -10.10 to 8.35; prespecified noninferiority margin -15%; P=.001). Reductions in myoma and uterine volumes and increases in hemoglobin levels were comparable in the two groups. Relugolix was associated with an earlier effect on menstrual bleeding than leuprorelin (pictorial blood loss assessment chart score of less than 10, 64.2% vs 31.7% [relugolix-leuprorelin difference 32.5%; 95% CI: 20.95-44.13%] for weeks 2-6 and pictorial blood loss assessment chart score of 0, 52.6% vs 21.8% [30.7%; 95% CI: 19.45-42.00%] for weeks 2-6) and faster recovery of menses after treatment discontinuation (relugolix median [Q1, Q3], 37 days [32.0, 46.0]; leuprorelin median, 65 days [54.0, 77.0]). Adverse events and bone mineral density loss were similar between relugolix and leuprorelin treatment groups.ConclusionIn women with uterine leiomyomas, once-daily treatment with relugolix, an oral gonadotropin-releasing hormone antagonist, demonstrated noninferiority to monthly leuprorelin for improvement of heavy menstrual bleeding at 6-12 weeks of treatment, had a more rapid effect on menstrual bleeding, and was generally well tolerated.Clinical Trial RegistrationClinicalTrials.gov, NCT02655237; JAPIC Clinical Trial Information, JapicCTI-163128.Funding SourceTakeda Pharmaceutical Company Limited and an affiliate of NovaQuest Capital Management LLC.

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