Uterine fibroids affect up to two-thirds of all women.1 The current medical treatment options for uterine fibroids include on- and off-label use of oral contraceptives, hormonal intrauterine devices, gonadotropin-releasing hormone (GnRH) receptor agonists, and progestins. Data on the oral GnRH antagonist elagolix, US Food and Drug Administration–approved to treat endometriosis, were presented at the 2019 Annual Clinical and Scientific Meeting of the American College of Obstetricians and Gynecologists.
In the Eularis I trial, a total of 412 women with heavy menstrual bleeding (>80 mL/cycle of menstrual blood loss) were included in the double-blind, randomized, placebo-controlled, 6-month, phase 3 study. Women were premenopausal, ranged in age from 18 to 51 years, and were assigned in a 1:1:2 ratio to placebo, elagolix 300 mg twice daily, or elagolix 300 mg twice daily in combination with 1 mg estradiol/0.5 mg norethindrone acetate once-daily add-back therapy. A total of 328 women completed treatment.
At 6 months, 84.1%, 68.5%, and 8.7% of women taking elagolix alone, elagolix plus estradiol/norethindrone acetate, and placebo experienced a bleeding reduction that was 50% or greater from baseline.
Half of women who were treated with elagolix plus hormonal add-back therapy experienced adverse events, compared with 80% of women who took elagolix alone and 38% of women taking placebo. At study conclusion, the change from baseline for lumbar spine bone mass density was not significantly different from placebo for elagolix plus hormonal add-back therapy, but it was significantly different for elagolix alone compared with placebo.2
A second study of safety and efficacy, which also was a double-blind, randomized, placebo-controlled, 6-month, phase 3 study, found that 76% of women randomly assigned to elagolix plus estradiol/norethindrone acetate experienced a bleeding reduction that was 50% or greater from baseline.3
Both EULARIS studies were funded by AbbVie, Inc.