This is a randomised, double-blind, multicentre study to evaluate the efficacy, safety, PK, PD, and immunogenicity of SB16 compared to Prolia® in postmenopausal women with osteoporosis.

Subjects will be randomised in a 1:1 ratio to receive either SB16 or Prolia®. At Month 12, subjects in Prolia® treatment group will be randomised again in a 1:1 ratio to either continue on Prolia® treatment or be transitioned to SB16 treatment. Investigational product (60 mg in 1 mL of SB16 or Prolia®) will be given subcutaneously every 6 months up to Month 12, and the last assessment will be done at Month 18.

Inclusion Criteria:

• Postmenopausal women who are 55 to 80 years of age at Screening
• Ambulatory and visually unimpaired to participate in the study at Screening, in the opinion of the Investigator
• Absolute BMD consistent with T-score at the total hip or lumbar spine of -4 and -2.5 at Screening
• At least three evaluable vertebrae within L1 to L4, one evaluable femoral neck, and one evaluable hip joint for BMD measurement at Screening
• Biologic naïve at Screening
• Body weight of 50 kg and 90 kg at Screening

Exclusion Criteria:

• One severe or more than two moderate vertebral fractures on spinal X-ray according to Genant classification at Screening
• History of hip fracture or bilateral hip replacement at Screening
• Uncorrected vitamin D deficiency at Screening
• Hypercalcemia or hypocalcaemia at Screening
• Inadequate haematological function at Screening
• Inadequate renal or hepatic function at Screening
• Known allergic reactions, hypersensitivity, or intolerance to denosumab or to any ingredients of the IP, including latex allergy or hereditary problems of fructose intolerance at Screening
• May not tolerate long-term calcium or vitamin D supplementation or subject with malabsorption of calcium or vitamin D supplements, in the opinion of the Investigator, at Screening
• Use of any of the medications that can affect BMD
• Use of any non-biologic IP that is not indicated for osteoporosis from another study or use of an investigational device at Screening
• Non-osteoporosis medical conditions that can affect BMD at Screening
• Any clinically significant disease or disorder or laboratory abnormality which, in the opinion of the Investigator, would prevent the subject from completing the study or the interpretation of the study results at Screening and Randomisation