AbbVie, a global biopharmaceutical company in cooperation with Neurocrine Biosciences, has announced detailed results from a phase 2b clinical trial evaluating the efficacy and safety of elagolix alone or in combination with add-back therapy (estradiol/norethindrone acetate) compared to placebo.  The data demonstrated that elagolix, with and without add-back therapy, met the primary efficacy endpoint of reduced heavy menstrual bleeding as compared to placebo (p<0.001). These results were shared for the first time in an oral presentation at the third Congress of the Society of Endometriosis and Uterine Disorders (SEUD) in Singapore.

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. African American women are more likely to experience fibroids and do so at a younger age. Fibroids can be asymptomatic, but in some women, fibroids can cause symptoms such as heavy menstrual bleeding, painful periods, vaginal bleeding at times other than menstruation, and anemia.

"A majority of premenopausal women will be diagnosed with uterine fibroids and it is the leading indication for hysterectomy in the United States," said James A. Simon, MD, clinical professor of obstetrics and gynecology, George Washington University, and medical director, Women's Health & Research Consultants in Washington, D.C. "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."

The study's primary endpoint assessed the change in menstrual blood loss from baseline to month six utilizing the alkaline hematin method, a standard measurement for menstrual blood loss. The effects of elagolix on heavy menstrual bleeding were rapid as evidenced by a significant reduction in the number of heavy bleeding days based on assessment at month six compared to placebo.  Women treated with elagolix had significant increases in hemoglobin concentration from baseline to month six compared to placebo. Uninterrupted treatment with elagolix was associated with decreased symptom severity and improved quality of life as assessed by the Uterine Fibroid Symptom and QoL (UFS-QoL) questionnaire.

"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, M.D., vice president, development and chief medical officer, AbbVie. "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 phase 2b uterine fibroids study (M12-813) was a 24-week, multicenter, double-blind, randomized, placebo-controlled, parallel group clinical trial that evaluated elagolix in women with heavy uterine bleeding associated with uterine fibroids. It was conducted in 567 premenopausal women, age 18 to 51, at 100 sites in the United States, Canada, Puerto Rico, Chile and the United Kingdom.  The two cohort design study evaluated the safety and efficacy of two elagolix treatment regimens (300mg BID and 600mg QD) alone and in combination with two different strengths of add-back therapy (estradiol/norethindrone acetate). The data presented were results from the 300mg cohort.  Results from the 600mg cohort were similar and will be reported in a future publication.

The most common adverse events reported were hot flush, headache and insomnia, which occurred more frequently in the elagolix treatment groups compared to placebo. Add-back therapy reduced the incidence of hot flushes in a dose-dependent manner. All elagolix treatment groups had a decrease in mean endometrial thickness from baseline to month six compared to placebo and there were no adverse endometrial findings from the endometrial biopsies at baseline or month six. 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.

The phase 3 elagolix uterine fibroids program includes two replicate, pivotal, six-month efficacy and safety studies followed by a six-month safety and efficacy extension study. The primary endpoint in phase 3 studies will assess the reduction in heavy menstrual bleeding compared to placebo as measured by the alkaline hematin method.