A Study Comparing Amorphous Calcium Carbonate (ACC) Versus Crystalline Calcium CCS) in Hypoparathyroidism Patients

Primary objective:

Phase I Proof of concept: treatment with smaller doses of elemental calcium from ACC compared to CCS can maintain target serum calcium (corrected for albumin) values (7.0-10.0 mg/dL).

Phase II To test the hypothesis that treatment with smaller doses of elemental calcium from ACC compared to CCS can maintain target serum calcium (corrected for albumin) values (7.0-10.0 mg/dL).

Secondary objectives:

Phase I

• ACC dose selection - to confirm the conversion factor of ACC from CCS
• To determine the effect of food on ACC absorption

Phase II

• To test the hypothesis that treatment with smaller doses of elemental calcium from ACC compared to CCS will not cause an increase in hypercalciuria in patients with hypoparathyroidism
• To test the hypothesis that smaller doses of elemental calcium from ACC can reduce the side effects related with high calcium consumption.

Amorphical has a strong basis to believe that the ACC product is better absorbed compared to the commercially available CCS products and therefore, can maintain desirable target albumin corrected calcium values in serum (CA) with smaller doses of elemental calcium from ACC. As results, the burden of taking high doses of calcium supplementation along with the side effects of the standard therapy (gastrointestinal discomfort and hypercalciuria) will be reduced.

Testing serum CA and urine calcium values in subjects with hypoparathyroidism may provide a straightforward method to test this hypothesis.

The study is designed to be conducted with extra precaution in order to avoid disturbing the fragile balance between CA levels in serum and calcium levels urine. The crossover design of phase II of the study allows a more accurate and reliable comparison of results attributable to the specific treatment within the same individual. In addition, the subjects will continue consuming all their routine medication throughout the trial. The subjects in the control arm will consume their routine calcium supplement doses thus, will be treated with a standard of care.