Relugolix combination therapy in Black/African American women with symptomatic uterine fibroids: LIBERTY Long-Term Extension study

Background: In the LIBERTY Long-Term Extension study, once-daily relugolix combination therapy (40 mg relugolix, estradiol 1 mg, norethindrone acetate 0.5 mg) substantially improved uterine fibroid-associated heavy menstrual bleeding throughout the 52-week treatment period in the overall study population. Objective: Black or African American women typically experience a greater extent of disease and symptom burden of uterine fibroids vs other racial groups and have traditionally been underrepresented in clinical trials. This secondary analysis aimed to assess the efficacy and safety of relugolix combination therapy in the subgroup population of Black or African American women with uterine fibroids in the LIBERTY Long-Term Extension study. Study Design: Black or African American premenopausal women (aged 18–50 years) with uterine fibroids and heavy menstrual bleeding who completed the 24-week randomized, placebo-controlled, double-blind LIBERTY 1 (identifier: NCT03049735) or LIBERTY 2 (identifier: NCT03103087) trials were eligible to enroll in the 28-week LIBERTY Long-Term Extension study (identifier: NCT03412890), in which all women received once-daily, open-label relugolix combination therapy. The primary endpoint of this subanalysis was the proportion of Black or African American treatment responders: women who achieved a menstrual blood loss volume of <80 mL and at least a 50% reduction in menstrual blood loss volume from the pivotal study baseline to the last 35 days of treatment by pivotal study randomized treatment group. The secondary outcomes included rates of amenorrhea and changes in symptom burden and quality of life. Results: Overall, 241 of 477 women (50.5%) enrolled in the LIBERTY Long-Term Extension study self-identified as Black or African American. In Black or African American women receiving continuous relugolix combination therapy for up to 52 weeks, 58 of 70 women (82.9%; 95% confidence interval, 72.0%–90.8%) met the treatment responder criteria for reduction in heavy menstrual bleeding (primary endpoint). A substantial reduction in menstrual blood loss volume from the pivotal study baseline to week 52 was demonstrated (least squares mean percentage change: 85.0%); 64.3% of women achieved amenorrhea; 59.1% of women with anemia at the pivotal study baseline achieved a substantial improvement (>2 g/dL) in hemoglobin levels; and decreased symptom severity and distress because of uterine fibroid-associated symptoms and improvements in health-related quality of life through 52 weeks were demonstrated. The most frequently reported adverse events during the cumulative 52-week treatment period were hot flush (12.9%), headache (5.7%), and hypertension (5.7%). Bone mineral density was preserved through 52 weeks. Conclusion: Once-daily relugolix combination therapy improved uterine fibroid-associated heavy menstrual bleeding in most Black or African American women who participated in the LIBERTY Long-Term Extension study. The safety and efficacy profile of relugolix combination therapy in Black or African American women was consistent with previously published results from the overall study population through 52 weeks. Findings from this subanalysis will assist shared decision-making by helping providers and Black or African American women understand the efficacy and safety of relugolix combination therapy as a pharmacologic option for the management of uterine fibroid-associated symptoms.