Teriparatide (Forsteo) Treatment in Postmenopausal Women: Mechanism of Action

Inclusion Criteria

Subjects must:

• Have a bone mineral density T-score (at the lumbar spine or total hip) of less than or equal to -2.5
• Be female
• Be at least 5 years post menopausal (more than 5 years since their last menstrual period) but <85 years old.
• Be ambulatory
• Be able and willing to participate in the study and provide written informed consent
• Have a serum 25(OH)2 vitamin D3 >50 nmol/L (after vitamin D3 loading)

Exclusion Criteria

Patients will not be admitted to the study if they exhibit any of the following:

• Evidence of a clinically significant organic disease which could prevent the patient from completing the study
• A body mass index less than 18 or greater than 35
• Abuse of alcohol or use illicit drugs (information obtained from medical history) or who consumed more than 4 servings of any alcoholic beverage one day prior to the visit (i.e., subjects who might be binge drinkers)
• Any history of cancer within the past 5 years excluding skin cancer non melanomas
• Any history of ongoing conditions or diseases known to cause abnormalities of calcium metabolism or skeletal health including Paget's disease of bone
• Chronic renal disease (as defined by an estimated glomerular filtration rate of ≤ 30mL/min)
• Acute or chronic hepatic disease
• Malabsorption syndromes
• Hyperthyroidism as manifested by TSH outside the lower limit of the normal range
• Hyperparathyroidism
• Hypocalcemia or hypercalcemia
• Osteomalacia
• Cushing's syndrome
• Current use of glucocorticoid therapy
• A corrected serum calcium less than 2.2 mmol/L and a PTH above 100 ng/L (that persists after testing and treatment for vitamin D deficiency)
• A history of any known condition that would interfere with the assessment of DXA at either lumbar spine or femoral neck
• Markedly abnormal clinical laboratory parameters that are assessed as clinically significant by the investigator
• Any previous use of bisphosphonate
• Use any of the following medications within 12 months of starting study drug
• Any fluoride with the exception of use for oral hygiene
• Strontium Ranelate
• Other bone agents (e.g. SERM, isoflavones, HRT)
• Participation in another clinical trial involving active therapy 3 months prior to enrolment
• Less than 5 years since menopause
• Bilateral fractures in the measurement regions (hip, tibia and forearm)
• Recent fracture within the last 12 months
• Prior radiation therapy which may involve the skeleton
• Hypersensitivity to teriparatide or any of its excipients
• Unexplained elevations of alkaline phosphatase
• Any known contraindication to the use of teriparatide