AbbVie’s investigational drug elagolix (ABT-620) decreased heavy menstrual bleeding and improved quality of life in women with uterine fibroids — a condition in which a part of the uterus muscle wall starts growing abnormally.

Symptoms resemble those of endometriosis, and the drug — which is currently undergoing Phase 3 clinical trials for uterine fibroids — has already completed Phase 3 trials for endometriosis. If Phase 3 trials are successful, elagolix may become approved for endometriosis in 2018.

The Phase 2 clinical trial (NCT01441635) explored elagolix as the sole treatment — or in combination with estradiol/norethindrone acetate — comparing it to placebo in women with heavy menstrual bleeding associated with uterine fibroids. It showed that elagolix reduced menstrual bleeding both on its own and in combination with the add-back treatment.

Although many women have uterine fibroids without symptoms, they experience excessive menstrual bleeding and pain, eventually developing anemia. Uterine fibroids are the most common type of abnormal growth in a woman’s pelvis and can affect about 20-80 percent of women by age 50, according to Chicago-based AbbVie. Black women are more likely to experience fibroids, and do so at a younger age.

“A majority of premenopausal women will be diagnosed with uterine fibroids and it is the leading indication for hysterectomy in the United States,” James A. Simon, MD, clinical professor of obstetrics and gynecology at George Washington University, said in a press release.

AbbVie presented the trial results at the Third Congress of the Society of Endometriosis and Uterine Disorders (SEUD), held recently in Singapore.

“The results presented today demonstrate that 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,” said Simon, who is also medical director of Women’s Health & Research Consultants in Washington, D.C.

Elagolix rapidly reduced blood loss during menstrual bleeding, leading to better blood hemoglobin levels after six months of treatment. A questionnaire found that uninterrupted treatment with elagolix reduced the severity of symptoms and improved quality of life.

The study tested two doses of the drug — 300 mg and 600 mg. Only data from the group that received 300 mg were presented at the meeting. AbbVie will present data from the 600 mg group later.

“Current non-surgical treatments indicated for uterine fibroids are limited, and women suffering from heavy menstrual bleeding associated with uterine fibroids need more options,” said Rob Scott, MD, AbbVie’s chief medical officer. “The positive results from this clinical trial represent a significant milestone in the development of elagolix, support AbbVie’s ongoing Phase 3 uterine fibroids research and demonstrate our continued commitment to address complex and serious diseases.”

The most common side effects linked to elagolix were hot flushes, headache and insomnia. The use of add-back treatment lowered the rate of hot flushes.

Data also showed that elagolix reduced the thickness of the endometrium in all patients regardless of add-back treatment. Researchers also did not detect any adverse changes when examining endometriosis tissue samples.

Elagolix alone did lower the bone mineral density among participants, but this effect was reduced when the drug was given in combination with estradiol/norethindrone acetate.

Elagolix is developed in partnership with Neurocrine Biosciences. The drug acts as a gonadotropin-releasing hormone antagonist, taken as a pill. By blocking gonadotropin-releasing hormone, Elagolix changes the signaling of other hormones, that in turn lower the production of the female sex hormones estradiol and progesterone.

In October 2016, AbbVie reported positive data from two Phase 3 clinical trials of elagolix for endometriosis, showing that the treatment improved patients’ impressions of pain as well as their quality of life. The treatment is expected to be cheaper than surgical interventions for endometriosis.