This study is testing a new medicine called **OG-6219**. It is for women aged 18 to 49 who have pain from endometriosis, a health condition where tissue like the lining inside the uterus grows outside the uterus. This study will check how well OG-6219 works and if it is safe. The study will compare three different doses of OG-6219 to a placebo, which is a pill with no medicine in it. This study lasts for about 16 weeks, with a follow-up visit at the end to check on safety. Women who join will be chosen randomly to get either the OG-6219 or the placebo. Some women will also have extra blood tests during the study.

• Study lasts about 16 weeks with a follow-up visit.
• Participants must have been diagnosed with endometriosis by surgery.
• You can't join if you are pregnant, plan to become pregnant, or are breastfeeding.