Decreased Rescue Analgesic Use with Elagolix Treatment in Women with Endometriosis-Associated Pain [35G]

INTRODUCTION: Rescue analgesic use was evaluated in two phase 3 studies, wherein 6-months (M) of elagolix (an oral, non-peptide GnRH antagonist) treatment was associated with improved dysmenorrhea and nonmenstrual pelvic pain compared to placebo in women with endometriosis-associated pain. METHODS: Elaris EM-I (N=871) and Elaris EM-II (N=815) were randomized, double-blind, 6M, placebo-controlled phase 3 studies evaluating two elagolix doses (150mg once daily [QD] or 200mg twice daily [BID]) in women with moderate/severe endometriosis-associated pain. Women could use either naproxen and/or a single opioid as rescue analgesic (opioid varied by country). Daily pill counts were recorded in an electronic-diary. RESULTS: At baseline, the mean daily rescue analgesic pill count ranged 0.7-0.9 across studies/doses. The mean percent decrease from baseline in average daily rescue analgesic pill count (any analgesic) was significantly greater compared to placebo for elagolix 200mg BID at M3 in Elaris EM-I and M6 in both studies (M6-least-squares mean percent change; Elaris EM-I:placebo=-24.7%, 150mg QD=-40.3%, P=0.121, 200mg BID=-59.9%, P<0.001; Elaris EM-II:placebo=-23.1%, 150mg QD=-26.9%, P=0.810, 200mg BID=-75.3%, P<0.001). At M6 in each study, rescue analgesic use, based on percent change from baseline in average daily pill count, was significantly reduced compared to placebo for naproxen and opioid pill count in the 200mg BID dose group. CONCLUSION: It was previously shown that elagolix treatment (150mg QD and 200mg BID) decreased pain in women with moderate/severe endometriosis-associated pain at M3 and M6. The current analysis shows that women treated with elagolix 200mg BID had the greatest decrease in rescue analgesic use compared to placebo at M6.