Elagolix Reduces Fatigue in Patients With Moderate-to-Severe Endometriosis Pain [34G]

INTRODUCTION: Endometriosis-associated symptoms like menstrual and non-menstrual pelvic pain can be associated with fatigue. This study evaluated the impact of elagolix, an oral gonadotrophin-releasing hormone antagonist, on fatigue among endometriosis patients. METHODS: We conducted a phase III double-blind randomized placebo-controlled trial that enrolled premenopausal women with surgically-confirmed endometriosis diagnosis and moderate to severe endometriosis-related pain. A total of 872 patients were randomly assigned to placebo, elagolix 150 mg once daily (QD) or elagolix 200 mg twice daily (BID) for 6 months. Fatigue was assessed using Patient Reported Outcome Measurement Information System (PROMIS) Fatigue short form 6a at baseline, months 1, 3 and 6. Raw scores were converted to T- scores that are standardized based on a mean of 50 and a standard deviation (SD) of 10 for the general population (lower scores indicates less fatigue). Changes from baseline T-scores were compared between elagolix treatments and placebo using 1-way analysis of covariance using baseline scores as a covariate. RESULTS: At baseline, mean T-scores were more than one SD worse than population average [Least squared (LS) Means: 62.37, 64.16 and 63.93] for placebo, elagolix 150 mg QD and elagolix 200 mg BID, respectively. At month 3, elagolix 150 mg QD and elagolix 200 mg BID had greater improvements from baseline T-scores [LS mean change: -6.26 and -8.84 respectively; all p<0.05] compared to placebo [LS mean change:-4.61]. Improvements observed at month 3 persisted at month 6 (Each elagolix vs. placebo comparisons had p<0.01). CONCLUSION: Elagolix reduces fatigue in endometriosis patients with moderate to severe pain.