A Study to Investigate Efficacy and Safety of OG-6219 BID in 3 Dose Levels Compared With Placebo in Participants Aged 18 to 49 With Moderate to Severe Endometriosis-related Pain

Prior treatment

• Chronic pelvic and/or non-pelvic pain not caused by endometriosis that requires chronic analgesic or other chronic therapy
• Undiagnosed (unexplained), abnormal vaginal bleeding not associated with endometriosis within the past 6 months before screening.
• Used any medication that is either a sensitive substrate, moderate, or strong inhibitor or inducer of CYP3A4 within 30 days or 10 half-lives (whichever is longer) prior to the planned first day of dosing.

Other illness

• Surgical history of hysterectomy and/or bilateral oophorectomy
• Has an active sexually transmitted infection (STI) (eg, gonorrhea, chlamydia, or trichomonas).
• History of malignancy (except for basal cell or squamous cell skin cancer) before signing informed consent.
• Has a medical condition associated with hemolytic anemia
• Known human immunodeficiency virus infection, and/or acute or active, recurrent/relapsing, or chronic infection (eg, hepatitis A, B, or C virus)

Lab values

• History of family history of hereditary abnormal hemoglobin or an enzyme deficiency that can result in methemoglobinemia.
• Has a clinically significant abnormal ECG or QT interval prolongation

Other

• Presence of high-risk human papillomavirus (HPV).
• Intends to become pregnant or breast feed during study participation or has a known or suspected pregnancy.

• Pre-menopausal females of age 18 to 49 years old (inclusive) at the time of signing Informed Consent (V1).
• Surgically (laparoscopy or laparotomy) diagnosed with endometriosis
• Moderate to severe endometriosis-related pelvic pain
• Regular menstrual cycles
• Is not expected to undergo a planned gynecological surgery or other surgical procedures for treatment of endometriosis during study participation.
• Normal breast exam at V1. In participants of ≥40 years mammography or contrast-enhanced breast MRI performed within the last 12 months prior to Screening (V1) without clinically significant abnormal findings.
• Agree not to participate in another interventional study while participating in the present study.
• Able and willing to adhere to study procedures, including
• agree to use 2 forms of non-hormonal contraception throughout the study
• Must be willing and able to provide signed informed consent before any study-related activities
• Has demonstrated compliance with ≥75% of eDiary entries
• Has a negative pregnancy test