Long-Term Safety Study of Elagolix in Combination With Estradiol/Norethindrone Acetate for the Management of Heavy Menstrual Bleeding Associated With Uterine Fibroids in Premenopausal Women

Inclusion Criteria:

• Participant is a premenopausal female at the time of Screening.

• Participant has a diagnosis of uterine fibroids documented by a Pelvic Ultrasound [Transabdominal ultrasound (TAU) and transvaginal ultrasound (TVU)].

• Participant has Heavy Menstrual Bleeding (HMB) associated with uterine fibroids asevidenced by Menstrual Blood Loss (MBL) > 80 mL during each of two screening mensesas measured by the alkaline hematin method.

• Participant has negative urine and/or serum pregnancy test during Washout (ifapplicable) and/or Screening and just prior to first dose.

• Participant has an adequate endometrial biopsy performed during Screening, theresults of which show no clinical significant endometrial pathology.

Exclusion Criteria:

• Participant has screening pelvic ultrasound or Saline Infusion Sonohysterography (SIS) results that show a clinically significant gynecological disorder.

• Participant has history of osteoporosis or other metabolic bone disease.

• Participant has clinically significant abnormalities in clinical chemistry,hematology, or urinalysis.

• Participant has a history of major depression or post-traumatic stress disorder (PTSD) episode within 2 years of screening, OR a history of other major psychiatricdisorder at any time (e.g., schizophrenia, bipolar disorder).

• Participant is using any systemic corticosteroids for over 14 days within 3 monthsprior to Screening or is likely to require treatment with systemic corticosteroidsduring the course of the study. Over the counter and prescription topical, inhaled,intranasal or intra-articular injectable (for occasional use) corticosteroids areallowed.