AbbVie in cooperation with Neurocrine Biosciences Inc. announced positive top-line results from the first of two ongoing Phase 3 clinical trials, designed to evaluate the efficacy and safety of elagolix in premenopausal women with endometriosis. Results from the trial show that after six months of treatment, both doses of elagolix (150 mg once daily and 200 mg twice daily) met the study's co-primary endpoints. Endometriosis is associated with a multitude of symptoms, some of the most common of which include pain related to menstruation as well as chronic pelvic pain throughout the menstrual cycle, and is a cause of infertility.

The World Endometriosis Research Foundation estimates that endometriosis affects one in ten women during their reproductive years, representing approximately 176 million women worldwide. The observed safety profile of elagolix in this Phase 3 trial was consistent with observations from prior studies. Among the most common adverse events (AEs) were hot flush, headache, nausea and fatigue.

While most AEs were similar across treatment groups, some, such as hot flush and bone mineral density (BMD) loss were dose-dependent. Overall discontinuation rates were similar across treatment groups and discontinuations specifically due to AEs were 5.9%, 6.4%, and 9.7% for placebo, 150 mg once daily and 200 mg twice daily, respectively. The top-line results are from a six-month, group-level analysis.

Patients in the trial will continue on in either post-treatment follow-up or a blinded six-month extension study. AbbVie intends to present detailed results from this trial at a future medical conference. The Phase 3 trial (M12-665) is a 24-week, randomized, double-blind, placebo-controlled study designed to evaluate the safety and efficacy of elagolix in 872 women, age 18 to 49, with moderate-to-severe endometriosis-associated pain.

It is being conducted at approximately 160 sites in the United States, Puerto Rico and Canada. A second Phase 3, randomized, multinational, double-blind, placebo-controlled trial (M12-671) evaluating elagolix in patients with moderate-to-severe endometriosis-related pain is ongoing and results are expected in late 2015.