Informing Patient Selection for Elagolix Treatment of Heavy Menstrual Bleeding Associated With Fibroids [23B]

INTRODUCTION: Evaluate the efficacy of elagolix (300 mg BID) with add-back therapy (1 mg estradiol/0.5 mg norethindrone acetate [E2/NETA]) in various subgroups of women with heavy menstrual bleeding (HMB) associated with uterine fibroids (UF). METHODS: Data were pooled from two investigational, IRB approved, 6-month, phase 3 studies, Elaris UF-1 and UF-2, that evaluated premenopausal women (18–51 years) with HMB [>80 mL menstrual blood loss (MBL)/cycle; alkaline hematin methodology] and ultrasound-confirmed UF diagnosis. Subgroups analyzed include age, BMI, ethnicity, race, fibroid location based on FIGO classification, uterine and primary fibroid volume, and pregnancy history. Primary endpoint was the proportion of women with <80 mL MBL during the final month of treatment and ≥50% MBL reduction from BL to the final month of treatment. Secondary and other efficacy endpoints included mean change in MBL from baseline to final treatment month and amenorrhea. Adverse events (AEs) were monitored. RESULTS: In all subgroups of women who received elagolix+E2/NETA the proportion of responders to the primary endpoint, mean change in MBL from baseline to final treatment month, and proportion of women who achieved amenorrhea were statistically significant compared to placebo, consistent with the overall study population for the primary endpoint (72.2% vs 9.3%, P<.001), mean change in MBL (-172.5 mL vs -0.8 mL, P<.001), and amenorrhea (50.4% vs 4.5%, P<.001). Each subgroup AEs were consistent with the overall study population. CONCLUSION: Elagolix with add-back therapy was effective in reducing HMB associated with UF regardless of age, BMI, ethnicity, race, fibroid location based on FIGO classification, uterine and primary fibroid volume, and pregnancy history.