A Study to Evaluate the Safety and Effectiveness of Three Asoprisnil Doses in the Treatment of Women With Endometriosis

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 the safety and efficacy of asoprisnil 5, 10, and 25 mg tablets, compared to placebo, administered daily for 12 weeks to women with endometriosis, by assessing whether asoprisnil administration diminishes the pelvic pain, dysmenorrhea, dyspareunia, excessive bleeding, and analgesic use associated with this disease and lessens the subjects' perceived pain symptoms. Otherwise healthy women with surgically confirmed endometriosis will be enrolled.