Efficacy and safety of relugolix combination therapy in women with uterine fibroids and adenomyosis: subgroup analysis of LIBERTY 1 and LIBERTY 2

OBJECTIVE: To assess the effects of relugolix combination therapy in women with uterine fibroids (UFs) and concomitant ultrasound-diagnosed adenomyosis. DESIGN: This post hoc analysis used pooled data from completers of the pivotal LIBERTY studies. The subgroup of women with adenomyosis and UFs was compared with the overall study population on selected efficacy and safety endpoints. SUBJECTS: Premenopausal women (aged 18-50 years) with diagnosed UFs (confirmed by ultrasonography) and heavy menstrual bleeding (assessed by the alkaline hematin method). INTERVENTION: Once-daily relugolix combination therapy (40 mg relugolix, 1 mg estradiol, and 0.5 mg of norethindrone acetate) or placebo for 24 weeks, or delayed relugolix combination therapy (40 mg of relugolix monotherapy for 12 weeks, followed by relugolix combination therapy for 12 weeks). MAIN OUTCOME MEASURES: Endpoints included the percentage of women with concomitant adenomyosis, the proportion of treatment responders (achieved or maintained a menstrual blood loss <80 mL and ≥50% reduction in menstrual blood loss volume from baseline over the last 35 days of treatment), the proportion of women achieving or maintaining amenorrhea over the last 35 days of treatment, and the change from baseline to week 24 in uterine volume and adverse events. RESULTS: A total of 111 women (18.2%) had a baseline diagnosis of concomitant adenomyosis (37 in the relugolix combination therapy group, 45 in the delayed relugolix combination therapy group, 29 in the placebo group) and were included in this analysis. Of women with adenomyosis, 83.8% in the relugolix combination therapy group were treatment responders compared with 27.6% in the placebo group. Amenorrhea was achieved in 64.9% of women with adenomyosis treated with relugolix combination therapy and in 6.9% of women treated with placebo. The least square mean uterine volume of women with adenomyosis decreased by 22.2% and 5.8% in the relugolix combination therapy and placebo groups, respectively. Results for the above outcomes in the relugolix combination therapy population were similar to the delayed relugolix combination therapy group. CONCLUSION: Efficacy outcomes in women with adenomyosis and UFs were comparable with those in women from the overall LIBERTY study population. CLINICAL TRIAL IDENTIFICATION NUMBER: LIBERTY 1, 2016-003727-27 (EudraCT) and NCT03049735; LIBERTY 2, 2016-005113-50 (EudraCT) and NCT03103087.