INTRODUCTION: Adenomyosis and uterine fibroids (UFs) may coexist in women with heavy menstrual bleeding (HMB). Relugolix combination therapy (Relugolix-CT: relugolix 40 mg, estradiol 1 mg, norethindrone acetate 0.5 mg) is approved in the United States to treat HMB associated with UFs and moderate-to-severe pain associated with endometriosis. A post-hoc analysis of the pivotal, 24-week LIBERTY 1 and 2 studies evaluated the efficacy of Relugolix-CT versus placebo in the subgroup with ultrasound evidence of adenomyosis. METHODS: Baseline ultrasound images from women enrolled in the replicate, IRB-approved LIBERTY studies were evaluated for adenomyosis using predefined criteria. Primary endpoint: proportion of study completers with baseline adenomyosis who were HMB responders, defined as 50% or higher reduction in menstrual blood loss (MBL) volume from baseline and less than 80-mL MBL over the last 35 days. Pooled LIBERTY 1 and 2 results are presented. RESULTS: Of women who completed the LIBERTY studies, 111/610 (18.2%) had ultrasound evidence of adenomyosis at study entry. The prevalence of adenomyosis was similar between treatment groups (18.3% and 14.0% for Relugolix-CT and placebo, respectively). In this subgroup, 83.8% of women treated with Relugolix-CT were HMB responders versus 27.6% of women who received placebo; responders in the overall population were 72.3% and 16.8%, respectively. Additionally, 64.9% of women in this subgroup who received Relugolix-CT were amenorrheic over the last 35 days of treatment, versus 6.9% of women treated with placebo. CONCLUSION: Relugolix-CT effectively reduced HMB in women with UFs and adenomyosis through 24 weeks. Efficacy in this subgroup of women was generally similar to the overall study population. [ABSTRACT FROM AUTHOR]