Primary Outcome Measures:
- Mean change from baseline in pelvic pain as assessed by daily diary [ Time Frame: Final month ] [ Designated as safety issue: No ]
- Mean change from baseline in dysmenorrhea as assessed by daily diary [ Time Frame: Final month ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- Change from baseline in pelvic pain and dysmenorrhea scores from the daily diary. [ Time Frame: Months 1,2,3 and Months 1-3 ] [ Designated as safety issue: No ]
- Change from baseline in dyspareunia and the combined pelvic pain/dysmenorrhea scores from the daily diary. [ Time Frame: Months 1,2,3 and Months 1-3 and the Final Month ] [ Designated as safety issue: No ]
- Change from baseline in the percentage of days with mild or greater combined pelvic pain/dysmenorrhea and moderate or greater combined pelvic pain/dysmenorrhea based on the daily diary. [ Time Frame: Months 1,2,3 and Months 1-3 and Final Month ] [ Designated as safety issue: No ]
- Change from baseline for pelvic pain, dysmenorrhea, dyspareunia, pelvic tenderness and induration scores assessed by the modified Biberoglu and Behrman pain scale. [ Time Frame: Months 1,2,3 and Final Visit ] [ Designated as safety issue: No ]
- Change from baseline in pelvic pain and dysmenorrhea assessed via the Visual Analog Scale. [ Time Frame: Months 1,2,3 and Final Visit ] [ Designated as safety issue: No ]
- Percent of subjects with "Yes" response to Global Efficacy question. [ Time Frame: Months 1,2,3 and Final Visit ] [ Designated as safety issue: No ]
- Change from baseline in analgesic use scores. [ Time Frame: Months 1,2,3, Months 1-3 and Final Visit ] [ Designated as safety issue: No ]
- Percent of subjects who achieve amenorrhea. [ Time Frame: Throughout the treatment period ] [ Designated as safety issue: No ]
- Change from baseline in Endometriosis Health Profile-30 (EHP-30) scores. [ Time Frame: Month 3 ] [ Designated as safety issue: No ]
- Change from baseline in Short Form-36 scores. [ Time Frame: Month 3 ] [ Designated as safety issue: No ]
- Change from baseline in both monthly bleeding scores and percentage of days with bleeding or spotting. [ Time Frame: Months 1-3 ] [ Designated as safety issue: No ]
- Change from Screening menses in bleeding intensity. [ Time Frame: First post-treatment menses ] [ Designated as safety issue: No ]
- Change from baseline in hemoglobin and hematocrit. [ Time Frame: Months 1,2,3 and Final Visit ] [ Designated as safety issue: No ]
Endometriosis, the presence of endometrial tissue outside the uterus, is a progressive, estrogen-dependent disease that occurs in menstruating women of reproductive age. Although all major endometriosis therapies are effective for the treatment of pain, no single treatment is superior to others in terms of efficacy. The major drawbacks of the current medical therapies are severe side effects such as hot flushes and osteoporosis. The objective of this study is to determine if a dose-response relationship exists between asoprisnil and endometriosis-associated pelvic pain and dysmenorrhea or to establish the lowest effective dose of asoprisnil in the treatment of pelvic pain and dysmenorrhea associated with endometriosis. Women with surgically confirmed endometriosis will be administered asoprisnil 0.5, 1.5, and 5 mg tablets or a placebo once daily for 3 months and efficacy will be assessed by improvement in pelvic pain, dysmenorrhea, dyspareunia, bleeding, analgesic use, global efficacy, and quality of life questionnaires. Safety will be based on assessments of the endometrium, lipid profiles, adverse events, and changes from baseline laboratory values and vital signs.