Endometriosis is a condition causing painful periods, affecting about 6-10% of women who can have babies. This study checks how well a drug named elagolix, combined with birth control pills (COC), helps women with endometriosis pain. A placebo is a pill that looks like real medicine but doesn't contain any active drug. Participants are randomly placed in one of three groups: one group gets elagolix, another group gets a placebo, and the third receives a combination. Women with endometriosis pain who still have periods can join. About 800 women will be part of the study in the United States, including Puerto Rico. For three months, they will take either elagolix or placebo with COC. After three months, all will take elagolix with COC for up to 18 months.
- The study lasts up to 18 months with regular clinic visits for check-ups.
- Participants may experience higher treatment burden compared to usual care.
- There is a 1 in 3 chance of receiving a placebo in the first 3 months.
Regular health assessments, blood tests, and questionnaires will monitor the drug's effects and safety.