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)