Safety & Tolerability of Cinacalcet in Pediatric Patients With Chronic Kidney Disease and Secondary Hyperparathyroidism

Inclusion criteria: * Subjects between the ages of 28 days to \< 6 years of age at enrollment (Czech Republic minimum age is ≥ 2 years of age at enrollment) * Screening plasma iPTH level \> 300 pg/mL (31.8 pmol/L) from the central laboratory, and not have received any cinacalcet therapy for at least 30 days prior to start of dosing * Screening corrected calcium from the central laboratory: * ≥ 9.4 mg/dL (2.35 mmol/L) if age 28 days to \< 2 years * ≥ 8.8 (2.2 mmol/L) if age ≥ 2 to \< 6 years * Serum phosphorus from the central laboratory: * ≥ 5.0 mg/dL (1.25 mmol/L) if age 28 days to \< 1 year * ≥ 4.5 mg/dL (1.13 mmol/L) if age ≥ 1 to \< 6 years * SHPT not due to vitamin D deficiency, per investigator assessment * Dry weight ≥ 7 kg at the time of screening Exclusion criterion: * History of congenital long QT syndrome, second or third degree heart block, ventricular tachyarrhythmias or other conditions associated with prolonged QT interval * Corrected QT interval (QTc) \> 500 ms, using Bazett's formula * QTc ≥ 450 to ≤ 500 ms, using Bazett's formula, unless written permission to enroll is provided by the investigator after consultation with a pediatric cardiologist * Use of grapefruit juice, herbal medications, or potent CYP 3A4 inhibitors (e.g., erythromycin, clarithromycin, ketoconazole, itraconazole) * Use of concomitant medications that may prolong the QTc interval (e.g., ondansetron, albuterol)