The purpose of the study is to evaluate the effect of treatment with romosozumab for 6 months compared with placebo on the percent changes in bone mineral density (BMD) at the lumbar spine, at the total hip and femoral neck in postmenopausal Chinese women with osteoporosis.

Inclusion Criteria:

• Subject is considered reliable and capable of adhering to the protocol, visit schedule, and medication intake according to the judgment of the investigator

• Subject is an ambulatory postmenopausal Chinese women, 55 to 90 years of age (inclusive) at the time of Screening. Postmenopause is defined as no spontaneous vaginal bleeding or spotting for 12 or more consecutive months prior to Screening

• Subject has a bone mineral density (BMD) T-score ≤-2.50 at the lumbar spine, total hip, or femoral neck, as assessed by the central imaging vendor at the time of Screening based on DXA scans, and using data for Caucasian women from the National Health and Nutritional Examination Survey (NHANES, 1998)

• Subject must have at least 1 of following independent risk factors for fracture:

  • History of fragility fracture (except hip fracture, a severe vertebral fracture or more than 2 moderate vertebral fractures)
  • Parental history of hip fracture
  • Low body weight (body mass index ≤19kg/m2)
  • Elderly (age ≥ 65 years)
  • Current smoker

• Subject has at least 2 vertebrae in the L1 to L4 region and at least 1 hip that are evaluable by dual-energy x-ray absorptiometry (DXA), as assessed by the central imaging vendor

Exclusion Criteria:

• Subject has a BMD T-score of ≤-3.50 at the total hip or femoral neck, as assessed by the central imaging vendor at the time of Screening based on DXA scans, and using data for Caucasian women from NHANES 1998

• Subject has a known history of hip fracture

• Subject has any severe (SQ3) or more than 2 moderate (SQ2) vertebral fractures, as assessed by the central imaging vendor based on the lateral spine x-ray at Screening

• Subject has a history of myocardial infarction (MI)

• Subject has a history of stroke

• Subject has a vitamin D insufficiency, defined as 25 (OH) vitamin D levels <20 ng/mL, as assessed by the central laboratory at Screening. Vitamin D repletion will be permitted and the subject may be retested once within the Screening Period

• Subject has used oral bisphosphonates:

  • Any doses received within 3 months prior to randomization
  • More than 1 month of cumulative use between 3 and 12 months prior to randomization
  • More than 3 years of cumulative use, unless the last dose was received ≥5 years prior to randomization

• Subject has used intravenous (iv) bisphosphonates:

  • zoledronic acid

    • Any doses received within 3 years prior to randomization
    • More than 1 dose received within 5 years prior to randomization

  • iv ibandronate, iv pamidronate, or iv alendronate (ALN)

    • Any doses received within 12 months prior to randomization
    • More than 3 years of cumulative use, unless the last dose was received ≥5 years prior to randomization

• Subject has used denosumab or any cathepsin K inhibitor:

  ● Any doses received within 18 months prior to randomization

• Subject has used tibolone, cinacalcet, or calcitonin:

  • Any doses received within 3 months prior to randomization

• Subject has used teriparatide (TPTD) or any parathyroid hormone (PTH) derivative:

  • Any doses received within 3 months prior to randomization
  • More than 1 month of cumulative use between 3 and 12 months prior to randomization

• Subject has used systemic oral or transdermal estrogen or selective estrogen receptor modulators (SERMs):

  ● More than 1 month of cumulative use within 6 months prior to randomization

• Subject has used strontium ranelate or fluoride:

  ● More than 1 month of cumulative use within 5 years prior to randomization

• Subject has used hormonal ablation therapy:

  ● More than 1 month of cumulative use within 6 months prior to randomization

• Subject has used systemic glucocorticosteroids:

  ● ≥5mg prednisone equivalent per day for more than 14 days within 3 months prior to randomization

• Subject has a history of osteonecrosis of the jaw (ONJ) or atypical femoral fracture (AFF)

• Subject has evidence of any of the following:

  1. Current, uncontrolled hyper- or hypothyroidism. Uncontrolled hyperthyroidism is defined as thyroid-stimulating hormone (TSH) and thyroxine (T4) outside of the normal range. Uncontrolled hypothyroidism is defined as TSH >10
  2. Current, uncontrolled hyperparathyroidism or history of hypoparathyroidism. Uncontrolled hyperparathyroidism is defined as PTH outside the normal range in subjects with concurrent hypercalcemia or PTH values >20 % above upper limit of normal (ULN) in normocalcemic subjects
  3. Current hypercalcemia or hypocalcemia, defined as albumin-adjusted serum calcium outside the normal range, as assessed by the central laboratory at the time of Screening. Albumin-adjusted serum calcium levels may be retested once in case of an elevated albumin-adjusted serum calcium level within 1.1xULN of the laboratory's reference ranges
  4. Subject has ≥3xULN of any of the following: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), or >ULN total bilirubin (≥1.5xULN total bilirubin if known Gilbert's syndrome). If subject has elevations only in total bilirubin that are >ULN and <1.5xULN, fractionate bilirubin to identify possible undiagnosed Gilbert's syndrome (ie, direct bilirubin <35 %)

Data from this trial may be requested by qualified researchers six months after product approval in the US and/or Europe, or global development is discontinued, and 18 months after trial completion. Investigators may request access to anonymized individual patient-level data and redacted trial documents which may include: analysis-ready datasets, study protocol, annotated case report form, statistical analysis plan, dataset specifications, and clinical study report. Prior to use of the data, proposals need to be approved by an independent review panel at www.Vivli.org and a signed data sharing agreement will need to be executed. All documents are available in English only, for a prespecified time, typically 12 months, on a password protected portal. This plan may change if the risk of re-identifying trial participants is determined to be too high after the trial is completed; in this case and to protect participants, individual patient-level data would not be made available.

Data from this trial may be requested by qualified researchers six months after product approval in the US and/or Europe or global development is discontinued, and 18 months after trial completion.

Qualified researchers may request access to anonymized IPD and redacted study documents which may include: raw datasets, analysis-ready datasets, study protocol, blank case report form, annotated case report form, statistical analysis plan, dataset specifications, and clinical study report. Prior to use of the data, proposals need to be approved by an independent review panel at www.Vivli.org and a signed data sharing agreement will need to be executed. All documents are available in English only, for a pre-specified time, typically 12 months, on a password protected portal.