Impact of demographic and clinical factors on elagolix plus add-back therapy effects on patient-reported nonbleeding symptoms in women with heavy menstrual bleeding and uterine fibroids: a post hoc analysis of data from two clinical trials

Objective: To investigate the efficacy of elagolix plus add-back therapy (estradiol [1 mg] and norethindrone acetate [0.5 mg] once daily) on patient-reported nonbleeding symptoms and menstrual bleeding associated with uterine fibroids (UFs) across different subpopulations.

Design: Post hoc analysis of two phase 3 clinical trials-Elaris UF-1 and UF-2.

Setting: A total of 76 (UF-1) and 77 (UF-2) US clinical sites.

Patients: Women (N = 591) with UFs and heavy menstrual bleeding.

Interventions: Elagolix (300 mg) twice daily with add-back therapy (the indicated dose for UF-associated heavy menstrual bleeding) vs. placebo for 6 months.

Main outcome measures: "Very much improved" or "much improved" change in nonbleeding symptoms (abdominal/pelvic pain, abdominal/pelvic pressure/cramping, back pain, and abdominal bloating) and menstrual bleeding measured using a Patient Global Impression of Change scale. Improvements were assessed in subpopulations stratified using baseline characteristics (age, race [self-reported], body mass index, and International Federation of Gynecology and Obstetrics fibroid classification).

Results: Across subpopulations, differences favored elagolix plus add-back therapy (vs. placebo) for most symptoms at month 1 and all symptoms at months 3 as well as 6. In patients with characteristics commonly associated with high disease burden (age >40 years, Black/African American), those treated with elagolix plus add-back therapy reported significantly greater improvements vs. placebo at months 1-6 (P<.05) for all nonbleeding and bleeding symptoms (P≤.05).

Conclusions: Premenopausal women with heavy menstrual bleeding and UFs receiving elagolix plus add-back therapy experienced significant improvements in nonbleeding as well as bleeding symptoms from months 1-6, regardless of baseline characteristics.

Clinical trial registration number: NCT02654054 and NCT02691494.