Expert Commentary

Can a drug FDA approved for endometriosis become a mainstay for nonsurgical treatment of HMB in women with fibroids?

Author and Disclosure Information

Elagolix is a GnRH antagonist that is approved in a 2-dose schedule for treatment of endometriosis. It is given orally and, as expected and clearly shown by the investigators in two identical, double-blind, randomized, placebo-controlled phase 3 trials, significantly reduces heavy menstrual bleeding (HMB) in women with fibroids. Because previous studies showed an increase in vasomotor symptoms and some negative impact on bone metabolism with elagolix, these studies, in addition to a placebo arm, included one arm with elagolix alone and one arm with “add-back therapy” that utilized estradiol and norethindrone acetate. The add-back therapy attenuated the hypoestrogenic effects of elagolix.



Schlaff WD, Ackerman RT, Al-Hendy A, et al. Elagolix for heavy menstrual bleeding in women with uterine fibroids. N Engl J Med. 2020;382:328-340.

Expert Commentary

Any women’s health care provider is extremely aware of how common uterine fibroids (leiomyomas) are in reproductive-aged women. Bleeding associated with such fibroids is a common source of medical morbidity and reduced quality of life for many patients. The mainstay treatment approach for such patients has been surgical, which over time has become minimally invasive. Finding a nonsurgical treatment for patients with fibroid-associated HMB is of huge importance. The recent failure of the selective progesterone receptor modulator ulipristal acetate to be approved by the US Food and Drug Administration (FDA) was a significant setback to finding an excellent option for medical management. A gonadotropin-releasing hormone (GnRH) antagonist like elagolix could become an incredibly important “arrow in the quiver” of women’s health clinicians.

Details about elagolix

As mentioned, elagolix was FDA approved in 2-dose regimens for the treatment of dysmenorrhea, nonmenstrual pelvic pain, and dyspareunia associated with endometriosis. One would expect that such a GnRH antagonist would reduce or eliminate HMB in patients with fibroids, although formal study had never been undertaken. Previous studies of elagolix had shown the most common adverse reaction to be vasomotor symptoms—hot flashes and night sweats. In addition, the drug shows a dose-dependent decrease in bone mineral density (BMD), although its effect on long-term bone health and future fracture risk is unknown.1

Study specifics. The current study by Schlaff and colleagues was performed including 3 arms: a placebo arm, an elagolix 300 mg twice daily arm, and a third arm that received elagolix 300 mg twice daily and hormonal “add-back” therapy in the form of estradiol 1 mg and norethindrone acetate 0.5 mg daily. The authors actually report on two phase 3 six-month trials that were identical, double-blind, and randomized in nature. Both trials involved approximately 400 women. About 70% of the study participants overall were black, and the average age was approximately 42 years (range, 18 to 51). At baseline, BMD scores were mostly in the normal range. HMB for inclusion was defined as a volume of more than 80 mL per month.

The primary end point was menstrual blood loss volume less than 80 mL in the final month and at least a 50% reduction in menstrual blood loss from baseline to the final month. In the placebo group, only 9% and 10%, respectively, met these criteria.

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