A Study of Amorphous Calcium Carbonate in Postmenopausal Women

This is an open-label study to evaluate the effect of DensityTM, amorphous calcium carbonate (ACC), in postmenopausal women, compared to FREEDOM substudy. Subjects with a BMD T-score between -4.0 to -2.5 will be invited to enroll into this study. After signed ICF, eligible subject who meet NHI reimbursement criteria for use of denosumab will be assigned to A arm, and subject who does not meet NHI reimbursement criteria for use of denosumab, or who is no willing to receive denosumab treatment during study period, even meet NHI reimbursement criteria will be assigned to B arm. A total of 205 subjects will be enrolled into this study, in which 142 subjects in A arm and 63 subjects in B arm. In A arm, subject will receive 5 DensityTM tablets (equal to 1000 mg calcium element) daily with injections of 60 mg of ProliaTM (denosumab) every 6 months at study site, while in B arm, eligible subject will receive 5 DensityTM tablets (equal to 1000 mg calcium element) daily only. DensityTM tablets will be administered as follows: 5 tablets will be taken after meal. In addition, all subjects with a baseline 25-hydroxyvitamin D level of 12 to 20 ng/ml will be given 800 IU of vitamin D3 daily, while those with a baseline level above 20 ng/ml received 400 IU of vitamin D3, both administered after meal. The study will consist of 7 clinical visits. Subjects will come to the clinics at Visit 1 (screening visit, Month -1), Visit 2 (regimen start, Day 0 in Month 0), and Visit 3 to 7 (follow-up visits, Month 1, 6, 12, 18, 24). BMD assessment and blood drawing will be performed before study medication administration and at Month 1, 6, 12, and 24.