A Study to Determine the Effects of NPSP795 on the Calcium-sensing Receptor in Subjects With Autosomal Dominant Hypocalcemia as Measured by PTH Levels and Blood Calcium Concentrations
A Study to Determine the Effects of NPSP795 on the Calcium-sensing Receptor in Subjects With Autosomal Dominant Hypocalcemia as Measured by PTH Levels and Blood Calcium Concentrations
This is an open-label study looking at the effects of NPSP795 (a selective calcium receptor
 antagonist) on activating mutations of the Calcium-sensing receptor in patients with
 Autosomal Dominant Hypocalcemia. Patients with ADH have low blood calcium levels and an
 inappropriately increased renal calcium excretion, decreased renal phosphate excretion, and
 hyperphosphatemia. PTH and blood calcium levels will be tested during and after the IV
 infusion of NPSP795. Concentrations of NPSP795 and length of time of IV infusion will vary
 depending on measured levels of ionized calcium.
Inclusion Criteria:

 -  Subjects with a heterozygous activating mutation of the CaSR gene (ADH); if not
 previously confirmed, genetic testing will be performed at the screening visit

 -  At least 18 years of age

 -  Body mass index (BMI) ≥ 18.5 to < 39 kg/m2

 Exclusion Criteria:

 -  Diseases or conditions that might compromise any major body system or interfere with
 the pharmacokinetics of NPSP795

 -  History of treatment with PTH 1-84 or 1-34 within the previous 6 months

 -  History of hypocalcemia requiring frequent IV calcium infusions

 -  History of hypocalcemic seizure within the past 3 months

 -  Blood 25-hydroxy vitamin D level < 25 ng/mL. If subjects have a blood 25-hydroxy
 vitamin D level < 25 ng/mL at the outpatient screening visit, they will be prescribed
 vitamin D replacement. Once the 25-hydroxy vitamin D level is > 25 ng/mL, the subject
 will be eligible to continue on to the treatment phase of the study

 -  Estimated glomerular filtration rate (GFR) < 25 mL/minute, and/or abnormal hepatic,
 hematologic, and/or clotting function

 -  12 lead resting electrocardiogram (ECG) with clinically significant abnormalities

 -  Concomitant medications with the potential to interfere with NPSP795 metabolism

 -  History of thyroid or parathyroid surgery