Objective

In this post hoc analysis, we evaluated the impact of elagolix on dysmenorrhea and nonmenstrual pelvic pain across menstrual period (bleeding days) and nonmenstrual (nonbleeding) days.

Methods

Data from two randomized, 6-month, placebo-controlled trials (Elaris Endometriosis (EM)-I and EM-II) of elagolix (150 mg once daily (QD) and 200 mg twice daily (BID)) in premenopausal women with moderate to severe endometriosis-associated pain (N = 1686) were pooled. Women recorded the presence of menstrual period and severity of dysmenorrhea or nonmenstrual pelvic pain in a daily electronic diary.

Results

At baseline, women in the placebo group and both elagolix treatment groups reported moderate or severe dysmenorrhea, on average, 81% of their menstrual period days and moderate/severe nonmenstrual pelvic pain, on average, 56% of their nonmenstrual (nonbleeding) days. Compared with placebo at month 6, elagolix-treated women had a significantly lower mean (standard deviation (SD)) percentage of menstrual period days with moderate or severe dysmenorrhea (elagolix 150 mg QD = 52.4 (38.9), p = 0.002; elagolix 200 mg BID = 38.5 (43.6), p < 0.001, placebo = 61.3 (33.7)) and a significantly lower mean (SD) percentage of nonmenstrual (nonbleeding) days with moderate or severe nonmenstrual pelvic pain (elagolix 150 mg QD = 31.1 (35.8), p < 0.001; elagolix 200 mg BID = 19.7 (29.9), p < 0.001; placebo = 35.6 (33.9)).

Conclusion

Following 6 months of elagolix treatment, women who still menstruated had a lower proportion of menstrual period days with moderate or severe dysmenorrhea compared with placebo, demonstrating pain reduction despite continued menses. Additionally, pain did not shift from dysmenorrhea to nonmenstrual pelvic pain, as the percentage of days with moderate or severe nonmenstrual pelvic pain was also reduced for elagolix-treated women compared with placebo.

Trial registration

The Elaris EM-I study is registered with the US National Library of Medicine, www.ClinicalTrials.gov, NCT01620528. The Elaris EM-II study is registered with the US National Library of Medicine, www.ClinicalTrials.gov, NCT01931670. Both studies are registered with the EU Clinical Trial Register, www.clinicaltrialsregister.ed, 2011-004295-11.

Objective

The aim of this study was to estimate the efficacy of elagolix, an oral gonadotropin-releasing hormone (GnRH) antagonist, for the treatment of endometriosis-associated pelvic pain.

Methods

This was a phase II, randomized, placebo-controlled parallel group study conducted at 37 US centers, consisting of an 8-week double-blind period followed by a 16-week open-label period. Patients were 137 women aged 18 to 49, with laparoscopically confirmed endometriosis and moderate to severe nonmenstrual pelvic pain and dysmenorrhea, who were administered elagolix 150 mg daily or placebo. The primary outcomes of the study were the daily assessment of dysmenorrhea, nonmenstrual pelvic pain and dyspareunia using a modified Biberoglu-Behrman scale.

Results

During the double-blind period, there were significantly greater mean reductions from baseline to week 8 in dysmenorrhea (-1.13 ± 0.11 vs. -0.37 ± 0.11, p<0.0001), nonmenstrual pelvic pain (-0.47 ± 0.07 vs. -0.19 ± 0.07, p = 0.0066), and dyspareunia scores (-0.61 ± 0.10 vs. -0.23 ± 0.10, p = 0.0070) in the elagolix group compared with placebo. Continued improvements were observed during the open-label treatment regardless of initial treatment allocation. Elagolix treatment was also associated with significant improvements in quality-of-life measures during the double-blind and open-label periods. The most common adverse events occurring with elagolix were nausea, headache and hot flush, each in 9.9% of patients.

Conclusion

Elagolix effectively reduced endometriosis-associated pelvic pain over a 24-week period and was well-tolerated.

Endometriosis is a chronic, estrogen-dependent condition that causes dysmenorrhea and pelvic pain. Elagolix, an oral, nonpeptide, gonadotropin-releasing hormone (GnRH) antagonist, produced partial to nearly full estrogen suppression in previous studies.We performed two similar, double-blind, randomized, 6-month phase 3 trials (Elaris Endometriosis I and II [EM-I and EM-II]) to evaluate the effects of two doses of elagolix - 150 mg once daily (lower-dose group) and 200 mg twice daily (higher-dose group) - as compared with placebo in women with surgically diagnosed endometriosis and moderate or severe endometriosis-associated pain. The two primary efficacy end points were the proportion of women who had a clinical response with respect to dysmenorrhea and the proportion who had a clinical response with respect to nonmenstrual pelvic pain at 3 months. Each of these end points was measured as a clinically meaningful reduction in the pain score and a decreased or stable use of rescue analgesic agents, as recorded in a daily electronic diary.A total of 872 women underwent randomization in Elaris EM-I and 817 in Elaris EM-II; of these women, 653 (74.9%) and 632 (77.4%), respectively, completed the intervention. At 3 months, a significantly greater proportion of women who received each elagolix dose met the clinical response criteria for the two primary end points than did those who received placebo. In Elaris EM-I, the percentage of women who had a clinical response with respect to dysmenorrhea was 46.4% in the lower-dose elagolix group and 75.8% in the higher-dose elagolix group, as compared with 19.6% in the placebo group; in Elaris EM-II, the corresponding percentages were 43.4% and 72.4%, as compared with 22.7% (P<0.001 for all comparisons). In Elaris EM-I, the percentage of women who had a clinical response with respect to nonmenstrual pelvic pain was 50.4% in the lower-dose elagolix group and 54.5% in the higher-dose elagolix group, as compared with 36.5% in the placebo group (P<0.001 for all comparisons); in Elaris EM-II, the corresponding percentages were 49.8% and 57.8%, as compared with 36.5% (P=0.003 and P<0.001, respectively). The responses with respect to dysmenorrhea and nonmenstrual pelvic pain were sustained at 6 months. Women who received elagolix had higher rates of hot flushes (mostly mild or moderate), higher levels of serum lipids, and greater decreases from baseline in bone mineral density than did those who received placebo; there were no adverse endometrial findings.Both higher and lower doses of elagolix were effective in improving dysmenorrhea and nonmenstrual pelvic pain during a 6-month period in women with endometriosis-associated pain. The two doses of elagolix were associated with hypoestrogenic adverse effects. (Funded by AbbVie; Elaris EM-I and EM-II ClinicalTrials.gov numbers, NCT01620528 and NCT01931670 .).