Elagolix meets primary endpoint for uterine fibroids in phase 2b trial

A phase 2b clinical trial has shown that elagolix, with and without the add-back therapy of estradiol/norethindrone acetate, met the primary efficacy endpoint of reducing heavy menstrual bleeding in women with uterine fibroids, according to a press release from AbbVie.

According to AbbVie, elagolix is an investigational, oral gonadotropin-releasing hormone (GnRH) receptor antagonist that blocks endogenous GnRH signaling by binding competitively to GnRH receptors.

“Current nonsurgical treatments indicated for uterine fibroids are limited, and women suffering from heavy menstrual bleeding associated with uterine fibroids need more options,” Rob Scott, MD, vice president of development and chief medical officer at Abbvie, said in the release. “The positive results from this clinical trial represent a significant milestone in the development of elagolix.”

The two-cohort design study evaluated the safety and efficacy of two elagolix treatment regimens — 300 mg twice a day and 600 mg per day — alone and in combination with two different strengths of estradiol/norethindrone acetate in 567 women aged 18 to 51 years who were premenopausal and experiencing heavy uterine bleeding as a result of uterine fibroids.

The release stated that the elagolix’s effects on heavy menstrual bleeding were rapid, and included a significant reduction in the number of heavy bleeding days and significant increases in hemoglobin concentration based on evaluation at the 6-month mark when compared to placebo. The company also stated that uninterrupted treatment with elagolix was connected to fewer severe symptoms and improved quality of life, as evaluated by the Uterine Fibroid Symptom and QoL questionnaire.

According to AbbVie, the most common adverse events were insomnia, headache and hot flush, which occurred more frequently in the elagolix treatment groups than the placebo group. In addition, the estradiol/norethindrone acetate therapy reduced the occurrence of hot flushes in a dose-dependent manner. All elagolix treatment groups had a decrease in mean endometrial thickness from baseline to month 6 compared with placebo and there were no adverse endometrial findings from the endometrial biopsies at baseline or at the 6-month mark. Also, reduction in bone mineral density associated with elagolix alone was attenuated when elagolix was co-administered with add-back therapy, with marginal effects on efficacy.

According to the release, the results for the 300-mg cohort and the 600-mg cohort were similar, and that results from the latter group will be reported in the future.

“... Elagolix was well-tolerated and has the potential to be an important treatment option for women suffering from heavy menstrual bleeding associated with uterine fibroids,” James A. Simon, MD, medical director at Women’s Health and Research Consultants, said in the release.

Phase 3 trials involving elagolix for the management of uterine fibroids are ongoing, according to Abbvie.

Disclosure: Scott works for Abbvie. Healio Family Medicine was unable to confirm Simon’s relevant financial disclosures prior to publication.