An Extension Study to Evaluate the Efficacy and Safety of Elagolix in Premenopausal Women With Heavy Menstrual Bleeding Associated With Uterine Fibroids

Inclusion Criteria:

• Participant has completed the 6-Month Treatment Period of their respective PivotalStudy (either Study M12-815 or Study M12-817).
• Participant did not meet removal criteria in bone mineral density (BMD) decrease inthe spine, total hip and femoral neck at Month 6 of the Treatment Period of theirrespective Pivotal Study
• Participant has negative urine and/or serum pregnancy test(s) results wereconsistently negative during the Treatment Period of their respective Pivotal Studyand prior to first dose in this study.
• Participant's endometrial biopsy from the Month 6 Visit of their respective PivotalStudy shows no clinically significant endometrial pathology.

Exclusion Criteria:

• Participant met criteria for removal from therapy in her respective Pivotal Study.
• Participant is planning a pregnancy within the next 18 months.
• Participant has current suicidal markers as noted at the Month 6 visit of herrespective pivotal study.
• Participant has any new medical conditions that may be unsuitable for participation.
• Participant is using any systemic corticosteroids for over 14 days or is likely torequire treatment with systemic corticosteroids during the course of the study.Over-the-counter and prescription topical, inhaled, intranasal or injectable (foroccasional use) corticosteroids are allowed.