The purpose of this study is to determine whether BA058 is effective in building bone in postmenopausal women with osteoporosis.

This is a randomized, parallel-group, multi-center, dose-finding study to evaluate the effects of BA058 in the treatment of otherwise healthy postmenopausal women with osteoporosis.

Primary Inclusion Criteria:

• The patient has a bone mineral density T-score ≤ 2.5 at the lumbar spine or hip (femoral neck) by dual energy x-ray absorptiometry (DXA). Women with a bone mineral density T-score of 2.0 or lower and a prior low-trauma forearm, humerus, vertebral, sacral, pelvic, hip, femoral, or tibial fracture within the past 5 years, or who have an additional risk factor such as age 65 or greater or a strong maternal history of osteoporosis defined as a fracture related to osteoporosis or osteoporosis itself as determined by BMD criteria, are also study candidates.
• The patient is in good general health as determined by medical history and physical examination and is without evidence of clinically significant abnormality in the opinion of the Investigator.

Primary Exclusion Criteria:

• History of bone disorders (e.g., Paget's disease) other than postmenopausal osteoporosis.
• Prior treatment with approved or as yet unapproved bone-acting investigational agents.
• History of carcinoma, nephrolithiasis or urolithiasis within the past five years or osteosarcoma at any time.
• History of radiotherapy (radiation therapy).

For patients treated during the initial 6 months only, AEs were collected for 8 months (1 pre + 6 treatment + 1 post). For patients treated over the extended treatment period of 12 months, AEs were collected for 14 months (1 pre + 12 treatment + 1 post).

Method of routinely determining whether or not certain adverse events have occurred was by regular investigator assessment and regular laboratory testing.