This is a 2 year study to examine the effects of a new experimental medication on postmenopausal osteoporosis. This study will enroll approximately 375 postmenopausal women, and randomly assign them to 4 different doses of the test drug or to placebo. Measurements performed during the study include: bone mineral density scans, spine x-rays, laboratory blood and urine tests, height measurements and optional bone biopsy (at the end of 2 years).

Ages Eligible for Study:  45 Years   -   85 Years,  Genders Eligible for Study:  Female

Criteria

Inclusion Criteria:

• Postmenopausal for 5 or more years.
• Bone mineral density (BMD) T-score at the hip or spine of -2.0 or less.
• In a state of general health allowing for successful completion of the trial.
• Agreement to not use any medications to treat osteoporosis during the study.

Exclusion Criteria:

• History of prior osteoporotic fracture (unless declined treatment with or was ineligible for osteoporosis therapy).
• Past treatment with osteoporosis medications, steroids, hormone replacement, as well as various other medications that affect bone may be exclusionary. (Different exclusion criteria apply to each bone active drug. For example, any prior use of intravenous (IV) bisphosphonates is not permitted. By contrast, prior use of hormone replacement for several years is permitted if it has not occurred within the past 6 months. Please ask the study doctor for details).