The assessment of safety will be based on primarily on the frequency of adverse events, laboratory abnormalities, and serious adverse events suspected by the investigators to be related to study treatments. The AE collection period extends from the time of first study drug administration drug until study completion. The intensity of each AE will be characterized and classified into 1 of the 3 generic categories (mild, moderate, or severe). The number and percentage of patients with adverse events will be tabulated by treatment group, body system and preferred term. The periods for adverse event tabulation will be from dose administration up to next dose administration if a further dose is given, and from dose administration to EOS for the last dose administration of a patient.

Biomarker data from serum bone formation biomarkers: procollagen type I N-terminal propeptide, procollagen type I C-terminal propeptide, osteocalcin, and bone-specific alkaline phosphatase, and from serum bone resporption mbiomarkers: C-telopeptides of type I collagen cross-links, and N-telopeptides of type I collagen cross-links will be reported as concentration results, measured using a specific assay with a working range defined by the Lower limit of quantification and Upper limit of quantification. It will be considered a sign for efficacy, if any of the above show significant (2-sided, alpha=0.05) increase versus baseline in the BPS804 group on day 43.

Bone mineral density will be assessed by dual-energy X-ray absorptiometry of the lumbar spine. Analysis will include four vertebral levels from L1 to L4. Individual vertebral levels may be excluded due to artifact. Bone mineral density Z-scores will be used as these are a comparison of a patient's BMD to that of a patient of the same age, sex, and ethnicity. The comparison of change from baseline with the matching change in the reference group will be done by 2-sample t-tests (1-sided). It will be considered a sign for efficacy, if any of the above show significant (2-sided, alpha=0.05) increase versus baseline in the BPS804 group on day 141.