OPTAMISE: Clinical Effectiveness of Teriparatide After Alendronate or Risedronate Therapy in Osteoporotic Postmenopausal Women

ELIGIBILITY CRITERIA include: * Post-menopausal women who have used risedronate or alendronate continuously for at least 24 mos prior to enrollment * Dosing regimens allowable are continuous (ie, uninterrupted) daily or weekly formulations of risedronate (5 mg once daily \[OD\] or 35 or 30 mg once a week \[OAW\]) or alendronate (10 mg OD or 70 mg OAW), for a minimum of 24 months prior to enrollment into study * Lumbar spine or total hip BMD T-score 1ess than or equal to -2.0 and \>/= 1 prevalent osteoporotic fracture, or lumbar spine or total hip BMD T-score less than or equal to -2.5 with or without and \>/= 1 prevalent osteoporotic fracture. The qualifying values must be documented prior to enrollment * Vitamin D (25-hydroxyvitamin D) between 16 ng/ml and 80 ng/ml * Urine NTX \<50 nmol/mmol creatinine (to assure treatment compliance and bone turnover is in the pre-menopausal range) EXCLUSION CRITERIA include: * Impaired renal function, demonstrated by creatinine clearance \< 30 ml/min * Any condition or disease that may interfere with the evaluation of at least 2 lumbar vertebrae (not necessarily contiguous), determined in a screening radiograph by a radiologist at the central facility (eg, confluent aortic calcifications, severe osteoarthritis, spinal fusion, lumbar spine fractures) * Depot injection vitamin D \>10,000 IU in the past 9 months prior to starting the investigational product * Treatment with antiresorptive agents other than risedronate, alendronate, and hormone replacement therapy within the last 36 months before study entry (ie, ibandronate, pamidronate, etidronate, raloxifene, clodronate, or zoledronate) * Use of combination alendronate and risedronate, either simultaneously or sequentially, within 60 months prior to enrollment, or use of any anti-resorptive agent in combination with risedronate or alendronate