Study to Evaluate the Efficacy and Safety of PBK_L2201 in Postmenopausal Women With Osteoporosis

Inclusion Criteria: * Be a healthy ambulatory postmenopausal woman from 50 to 85 years of age (inclusive) with osteoporosis. * Be postmenopausal for at least 5 years. Postmenopausal status was established by a history of amenorrhea for at least 5 years and by an elevated serum follicle-stimulating hormone (FSH) value of ≥30 IU/L. * Be to have a bone mineral density (BMD) T score ≤ -2.5 and \> -5.0 at the lumbar spine or hip (femoral neck) by dual energy x-ray absorptiometry (DXA) and radiological evidence of 2 or more mild or one or more moderate lumbar or thoracic vertebral fractures, or history of low-trauma femoral, radius, humerus, sacral, pelvic, or ankle fracture within the past 5 years. Postmenopausal women older than 65 who meet the above fracture criteria but have a T score ≤ -2.0 and \> -5.0 may be enrolled. Women older than 65 who do not meet the fracture criteria may also be enrolled if their T score is ≤ -3.0 and \> -5.0 Exclusion Criteria: * History of more than 4 spine fractures, mild or moderate, or any severe fractures. * Presence of abnormalities of the lumbar spine that would prohibit assessment of spinal bone mineral density, defined as having at least 2 radiologically evaluable vertebrae within L1-L4. * Unevaluable hip Bone mineral density (BMD) or patients who had undergone bilateral hip replacement (unilateral hip replacement was acceptable).