A Phase 3B Study to Evaluate Bone Mineral Density With Long-Term Use of Relugolix Combination Tablet in Women With Uterine Fibroids or Endometriosis

A prospective, single-arm, open-label, Phase 3B study to assess the effect of continuous 48 months (4 years) of treatment with relugolix combination tablet (relugolix 40 mg/estradiol \[E2\] 1 mg/norethindrone acetate \[NETA\] 0.5 mg) on bone mineral density in premenopausal women with heavy menstrual bleeding associated with uterine leiomyomas (fibroids) and premenopausal women with moderate to severe pain associated with endometriosis. Approximately 1000 women (500 with heavy menstrual bleeding associated with uterine fibroids and 500 with moderate to severe pain associated with endometriosis) will receive relugolix combination tablet, during which time BMD will be assessed by dual-energy X-ray absorptiometry every 6 months. A subset of participants will be eligible to enter this study following completion of 1 year of treatment with relugolix combination therapy in MVT-601-050 (NCT04756037; SERENE) and will complete 3 years of treatment under this protocol. Upon completion of 48 months (4 years) of treatment or after early termination of treatment, participants will enter a 1-year post-treatment follow-up period during which time bone mineral density will be assessed at Month 6 and Month 12 following treatment cessation.