Treatment of Autonomous Hyperparathyroidism in Post Renal Transplant Recipients

- Received a kidney transplant ≥ 9 weeks at time of Screening and ≤ 24 months before first dose - May be the first kidney transplant or a repeat kidney transplant. - Subjects with a functional, stable kidney transplant, defined as MDRD estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m² (chromic kidney disease stage 3 or better) at Screening. - Men or women ≥ 18 years at the start of Screening (ie, time of informed consent). - Corrected total serum calcium > 10.5 mg/dL (2.63 mmol/L), defined as the mean of 2 values in Screening period. - iPTH > 100 pg/mL (10.6 pmol/L), during the Screening period (obtained at either Screen 1 or Screen 2).

- Received cinacalcet therapy post-transplant for more than 14 days cumulatively post-transplant. If cinacalcet therapy was received for a total of 14 days or less post-transplant, there must be a 4-week washout before subject is eligible for screening (Note: This does not exclude pre-transplant use of cinacalcet). - Anticipated parathyroidectomy within 6 to12 months after Randomization. - Ongoing therapy with bisphosphonates or use within 6 months prior to Screening. - Ongoing use of 1,25-dihydroxyvitamin D3 (including other active vitamin D metabolites or analogues) or use within 30 days prior to Screening. - Ongoing use of calcium supplements or use within 30 days prior to Screening. - Ongoing use of phosphate binders (calcium or non-calcium containing) or use within 30 days prior to Screening. - Ongoing use of a thiazide diuretic. - Subjects with a history of seizures who had a seizure within the 3 months prior to Randomization, which required adjustments to the seizure medication. - Acute Kidney Injury (AKI) or renal biopsy within 6 weeks prior to Screening, unless it is an institutional protocol-driven biopsy.