Clinical Trials

Inclusion Criteria:

1. History of hypoparathyroidism
2. Requirement for supplemental oral calcium treatment ≥ 1000 mg per day.
3. Requirement for active vitamin D therapy at a dose of ≥ 0.25 mcg per day . (i.e., ≥ 0.25 mcg calcitriol or equivalent per day).
4. Serum calcium levels within the laboratory normal range based on clinical chemistry lab results at Screening (central and/or local lab) and Treatment Period 1, Day -2 (central and/or local lab) or, if outside the normal range, considered as not significant by the Investigator.
5. Urinary calcium excretion ≥200 mg (5mmol)/24h, based on a 24-hour collection prior to check-in to the CRC at Treatment Period 1, Day -2 (central and/or local lab).
6. Serum magnesium level within the laboratory normal range at the screening examination or, if outside the normal range, considered as not significant by the Investigator.
7. Serum thyroid function tests within normal laboratory limits at screening, or if outside of the normal range, considered as not clinically significant by the Investigator.
8. Serum 25(OH) D level between the lower limit of normal and 1.5 fold the laboratory upper limit of normal at the first screening visit or, if outside the normal range, considered as not significant by the Investigator.
9. Serum creatinine < 1.5 mg/dL (<133 micromol/L) AND creatinine clearance > 60 mL/ minute(>1.002mL/s).

Exclusion Criteria:

1. Participation in any other investigational drug study within the last 3 months
2. Use of any of the following prior to study drug administration:
   1. 14 days: thiazide diuretics
   2. 30 days: loop diuretics, lithium, , systemic corticosteroid
   3. 3 months: calcitonin, cinacalcet hydrochloride, rhPTH(1-84) or N-terminal PTH or PTH-related peptide fragments or analogs
   4. Females only; changes in hormone replacement therapy within 3 months
   5. 6 months: fluoride tablets, oral bisphosphonates, methotrexate growth hormone, digoxin; raloxifene or similar selective estrogen receptor modulators
   6. 12 months: intravenous bisphosphonates, drug or alcohol abuse
3. History of a clinically significant disorder involving the cardiovascular, respiratory, renal, gastrointestinal, immunologic, hematologic, endocrine (with exception of the condition under study), or neurologic system(s) or psychiatric disease as determined by the Investigator.
4. Known history of hypoparathyroidism resulting from an activating mutation in the calcium sensing receptor (CaSR) gene or impaired responsiveness to PTH (pseudohypoparathyroidism).