This is a 3-arm, multicenter, double-blind, randomized, placebo-controlled study to evaluate the efficacy of DR-2001 in endometriosis-related symptoms, primarily nonmenstrual pelvic pain, over a 12-week treatment period.

This multicenter, double-blind, randomized, placebo-controlled study is designed to evaluate the ability of DR-2001 to produce beneficial changes in endometriosis-related symptoms, primarily nonmenstrual pelvic pain, over a 12-week treatment period. The overall study duration for each patient will be about 20 weeks.

Patients who meet all study entrance criteria will be randomly assigned to one of three treatment groups.

The change in endometriosis-related clinical symptoms will be assessed in two ways: through a combined physician/patient assessment and also with a patient self-assessment. Patients will undergo a gynecologic exam at each study visit.

Inclusion Criteria:

• Surgically sterilized (patient or partner), willing to use condoms throughout the study, or otherwise not at risk for pregnancy
• Diagnosis of endometriosis within the last 5 years
• Moderate or severe nonmenstrual pelvic pain
• Premenopausal
• Not pregnant or breastfeeding
• Regular (24-35 day) menstrual cycles for at least 2 months

Exclusion Criteria:

• Undiagnosed abnormal genital bleeding
• Any contraindication to the use of hormonal therapy
• Prior surgery for endometriosis
• GnRH analog therapy within 5 months
• Use of estrogens and/or progestins within 2 months
• Pain symptoms unrelated to endometriosis
• Any contraindication to the use of vaginal delivery systems