Conditions: Endometriosis
Keywords: bone mineral density,endometriosis,pelvic pain
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 174
Healthy volunteers: no

Brief summary:
This study is designed to evaluate the safety and beneficial effects of elagolix (NBI-56418) compared to placebo and leuprorelin (an approved endometriosis therapy) over a three month period followed by an additional three months of treatment on elagolix.

Detailed description:
The study followed a parallel-group design in which participants were randomized (1:1:1:1) to one of the following treatment groups for the first 12 weeks of dosing: 150 mg elagolix once daily (q.d.); 250 mg elagolix q.d.; placebo; or leuprorelin acetate depot injection 3.75 mg (monthly). Blinding was achieved using a double-dummy design. Following 12 weeks of dosing, participants continued in the study for an additional 12 weeks; participants randomized to elagolix continued to receive their assigned dose and participants randomized to placebo or leuprorelin acetate were re-randomized to receive one of the two doses of elagolix (150 mg q.d. or 250 mg q.d.) for 12 weeks in a double-blind fashion. Six weeks after the last dose of the study drug at the end of Week 24, a follow-up visit was performed (end of Week 30).

There was no pre-specified primary efficacy end point as there was no single key efficacy outcome measure in this exploratory Phase 2 study. For purposes of results reported here, Change From Baseline in the Monthly Mean Numerical Rating Score (NRS) for Endometriosis Pain is designated as the primary outcome measure.

Arms:
arm 1: Participants received placebo tablets once a day and placebo intramuscular injection once a month for 12 weeks. At the end of 12 weeks participants were re-randomized to receive one of the two doses of elagolix (150 mg or 250 mg) for 12 weeks. arm 2: Participants received elagolix 150 mg tablets once a day and placebo intramuscular injection once a month for 12 weeks. At the end of 12 weeks participants continued to receive elagolix 150 mg for an additional 12 weeks. arm 3: Participants received elagolix 250 mg tablets once a day and placebo intramuscular injection once a month for 12 weeks. At the end of 12 weeks participants continued to receive elagolix 250 mg for an additional 12 weeks. arm 4: Participants received placebo tablets once a day and leuprorelin acetate 1-month depot 3.75 mg intramuscular injection once a month for 12 weeks. At the end of 12 weeks participants were re-randomized to receive one of the two doses of elagolix (150 mg or 250 mg) for 12 weeks.

Interventions: intervention 1: Leuprorelin Acetate Depot intervention 2: Elagolix intervention 3: Placebo to Elagolix intervention 4: Placebo to Leuprorelin Acetate
Intervention descriptions: intervention 1: Leuprorelin acetate depot injection 3.75 mg administered as an intramuscular injection intervention 2: Elagolix tablets administered orally intervention 3: Placebo tablet administered orally intervention 4: Saline solution administered as an intramuscular injection

Protocol document: