Study to Evaluate Cinacalcet HCl in Pediatric Subjects With Chronic Kidney Disease

Inclusion Criteria:

- Subject's parent, or legally acceptable guardian, must sign an Independent Ethics
Committee (IEC) or Institutional Review Board (IRB) approved Informed Consent Form.

- Subjects 28 days to < 6 years of age with CKD and sHPT as diagnosed by principal
investigators, undergoing hemodialysis or peritoneal dialysis at the time of
screening (subjects 6 months or older should have been receiving dialysis for ≥ 1
months) and who have not received any cinacalcet HCl therapy for at least 2 weeks
prior to dosing on Day 1

- Free of any disease or condition (other than those diseases or conditions related to
their renal disease that, in the opinion of the investigator, would impact the
subject's safety or the integrity of the study data).

- Must weigh ≥ 6 kg at screening and at Day-1.

- Must be at least 30 weeks of gestational age.

- Physical examination must be acceptable to the investigator at screening and at Day
-1.

- Hemoglobin ≥ 8 g/dL at screening and at Day -1.

- Serum calcium within age-appropriate normal ranges per NKF-K/DOQI guidelines at
screening and at Day -1

- Normal or clinically acceptable ECG (12-lead reporting RR, PR, QRS, and QTc
intervals) at screening and at Day -1.

- Clinical laboratory tests that are acceptable to the investigator at screening and at
Day -1.

Exclusion Criteria

- Current or historic malignancy.

- Cardiac ventricular arrhythmias within 28 days prior to screening.

- A gastrointestinal disorder or surgery that could affect the absorption of drugs (eg,
pyloric stenosis or any gut-shortening surgical procedure prior to screening).

- A new onset of seizure or worsening of a pre-existing seizure disorder within 2
months prior to IP administration.

- Major surgery (defined as any surgical procedure that involves general anesthesia or
respiratory assistance) within 28 days prior to screening.

- Hepatic impairment indicated by elevated levels of hepatic transaminase or bilirubin
(aspartate aminotransferase (AST) ≥ 1.5 x upper limit of normal (ULN) OR alanine
aminotransferase (ALT) ≥ 1.5 x ULN OR total bilirubin ≥ 1 x ULN per institutional
laboratory range) at screening or Day-1.

- History of prolongation of the QT interval (eg, congenital long QT interval, second
or third degree heart block or other conditions which prolong the QT interval)

- Corrected QT Interval (QTc) > 500 ms during screening, using Bazett's formula

- QTc ≥ 450 and ≤ 500 ms during screening, using Bazett's formula, unless written
permission to enroll is provided by the investigator after consultation with a
pediatric cardiologist

- Known hypersensitivity to cinacalcet HCl or any of the excipients in cinacalcet HCl.

- Use of grapefruit juice, herbal medications or potent CYP 3A4 inhibitors (eg,
erythromycin, clarithromycin, ketokonazole, itraconazole) within the 14 days prior to
enrollment and during the study.

- Concurrent or within 28 days prior to enrollment use of medications that are
predominantly metabolized by the enzyme CYP2D6 and have a narrow therapeutic index
(eg, flecainide, vinblastine, thioridazine, tricyclic antidepressants such as
desipramine and imipramine, and beta-blockers such as metoprolol or carvedilol).

- Concurrent or within 28 days prior to enrollment use of medications that prolong QT
interval (eg, sotalol, amiodarone, erythromycin, or clarithromycin). Please refer to
the complete QT prolongation medication list at
http://www.crediblemeds.org/pdftemp/pdf/CompositeList.pdf

- Currently receiving treatment in another investigational device or drug study, or
less than 90 days since ending treatment on another investigational device or drug
study(s).

- Other investigational procedures while participating in this study are excluded.