The objective of this study is to determine the long-term safety of asoprisnil 10 mg when administered to postmenopausal women with Premarin® 0.625 mg

The objective of this study is to determine the long-term safety of asoprisnil 10 mg (2-5mg tablets) when taken with Premarin® 0.625 mg, by postmenopausal women, for 6 months after an initial 12 weeks in Study M00-198. Pharmacodynamic effects to be assessed include uterine bleeding pattern, endometrial biopsy results, and endometrial thickness. Safety assessments will include clinical laboratory results, physical examination with vital signs, pelvic and breast examinations, ultrasound results, and adverse events.

Inclusion Criteria:

• Successful completion of study M00-198
• Continued good general health
• Negative urine pregnancy test

Exclusion Criteria:

• History of known or suspected cancer other than basal cell carcinoma in last 5 years
• History of reproductive endocrine disorder
• Submucous or other symptomatic fibroid which would confound efficacy
• Ovarian mass
• Ongoing treatment with an excluded medication
• Stenosis of the cervix
• Any abnormal lab result the study-doctor considers significant.