A Study to Assess the Safety and Efficacy of 3 Doses of ALX1-11 (50, 75, and 100µg) in the Treatment of Postmenopausal Osteoporosis

Inclusion Criteria: * Post-menopausal women aged 50-75 years at Visit 1 (at least 5 years post cessation of menses, or FSH\>20 IU/L, serum estradiol \<110 pmol/L) * Vertebral bone mineral density at least 2.5 S.D. below the mean of young normals. Patients must have at least 2 measurable contiguous vertebral bodies in the lumbar region, L1-L4. * Ability to self administer injections * Ability and willingness to give informed consent Exclusion Criteria: * Evidence of 5 or more vertebral fractures * Evidence of 2 or more vertebral fractures in the region L1-L4 * Presence of significant cardiac disease as determined by history, physical examination and laboratory screens e.g. cardiac dysrhythmias. * Presence of significant hepatic, renal, pulmonary, gastrointestinal, hematological, endocrine, immunologic, neurological or psychiatric disease as determined by history, physical examination and laboratory screens. Specifically excluded are diseases known to contribute to osteoporosis: hyperparathyroidism, hyperthyroidism, glucocorticoid excess, hyper or hypocalcemia, Paget's disease, osteogenesis imperfecta, osteomalacia and severe scoliosis. * Evidence of lumbar fusions, osteophytes or excessive degenerative disease which precludes reasonable DXA measurement. * History or presence of cancer within the previous 5 years except for superficial basal cell and squamous cell carcinomas of the skin. * Treatment with any of the following therapies: * Any form of Estrogen within previous 6 months * Prior use of Etidronate for more that 2 treatment cycles (2weeks/cycle) and/or any use within prior 6 months * Any other bisphosphonate * Parathyroid Hormone use within 6 months * Fluoride (\>10 mg/day) within 12 months * Any form of Calcitonin within previous 4 months * Thyroid hormone within previous 4 months unless TSH levels found to remain within normal range * Other therapies known to influence bone metabolism\* within previous 4 months * Any investigational compound within previous 3 months * Abnormal serum Ca++ level: patients having two (2) consecutive serum calcium above 2.66 mmol/L (10.6 mg/dl) will be excluded. * History of positive test for Hepatitis B or C, or urine drug screen. * History of alcohol or drug abuse: an excess of alcohol is defined as more than 4 or any combination of more than four (4) of the following per day: 120 mL wine, 360 mL beer or wine cooler or 30 mL whiskey. * Weight more than 25% above ideal body weight, (minimum 45 kg) as listed in the Metropolitan Life Insurance Tables (Appendix 3) * Deemed unsuitable, in the opinion of the investigator, for any other reason. (\*Chronic or continued use of medication that may affect bone calcium metabolism, e.g. thiazide diuretics, oral or injectable steroids, antimitotics (methotrexate), heparin, anticonvulsants and supplements of Vitamin D in excess of 1,000 IU per day and Vitamin A in excess of 10,000 IU per day)