Elagolix Treatment for Endometriosis-Associated Pain: Results from a Phase 2, Randomized, Double-Blind, Placebo-Controlled Study

This Phase 2 study evaluated the safety and efficacy of elagolix for treating endometriosis-associated pain. A total of 155 women with laparoscopically confirmed endometriosis were randomized to placebo, elagolix 150 mg, or elagolix 250 mg once daily for 12 weeks. Placebo patients were rerandomized to elagolix and elagolix patients continued their dosing assignment for 12 additional weeks; the primary efficacy measure was changed from baseline in the monthly mean numerical rating scale for pain at week 12. Monthly mean (standard error of the mean) reductions were greater with elagolix versus placebo (-1.19 +/- 0.18, -1.25 +/- 0.18, and -0.88 +/- 0.18 for elagolix 150 mg, 250 mg, and placebo, respectively); differences were not statistically significant. Monthly mean dysmenorrhea and nonmenstrual pelvic pain scores were reduced with elagolix, with significant differences for dysmenorrhea at weeks 8 and 12 versus placebo (P < .05). Minimal bone mineral density changes were observed with elagolix treatment. In women with endometriosis-associated pain, elagolix demonstrated an acceptable efficacy and safety profile in this Phase 2 study.