Extension Study of Cinacalcet for Treatment of Secondary Hyperparathyroidism (SHPT) in Pediatric Patients With Chronic Kidney Disease on Dialysis

This extension study was designed to characterize the long-term safety and tolerability of cinacalcet in pediatric patients from Amgen Studies 20130356 (NCT02138838) and 20110100 (NCT01439867) who either had completed the parent study or were ongoing at the time an administrative decision was made to end the parent study. After enrolling into this study participants were administered cinacalcet for 28 weeks or until the time of renal transplant or parathyroidectomy, whichever occurred first. The treatment period was followed by a 4-week safety follow-up period.

Inclusion criteria

All subjects:

• Subject's legally acceptable representative has provided informed consent when the subject is legally too young to provide informed consent and the subject has provided written assent based on local regulations and/or guidelines prior to any Study 20140159 activities/procedures being initiated.
• Dialysate calcium concentration ≥ 2.5 mEq/L at day 1

All subjects with > 14 days between the last study visit in Study 20130356 or Study 20110100 and screening for Study 20140159:

• Subjects on anti-convulsant medication must be on a stable dose

All subjects from 20130356:

• Completed treatment through week 20 in the 20130356 study or on study at the time of Study 20130356 termination
• Dry weight ≥ 12.5 kg at day 1 of Study 20140159

Subjects Randomized to the 20130356 Standard of Care Arm Only:

• intact parathyroid hormone (iPTH) value ≥ 300 pg/mL (within 7 days of day 1 in Study 20140159)
• Corrected calcium value ≥ 8.8 mg/dL within 7 days of day 1 in Study 20140159

All Subjects from 20110100:

• Completed week 26 End of Study visit in the, 20110100 study or on study at the time of Study 20110100 termination
• Dry weight ≥ 7 kg at day 1 of Study 20140159

Exclusion criteria

General (studies 20130356 and 20110100):

• Currently receiving treatment in another investigational device or drug study, or less than 30 days since ending treatment on another investigational device or drug study(s), other than Amgen Studies 20130356 or 20110100.
• Other investigational procedures while participating in this study are excluded.
• Malignancy except non-melanoma skin cancers, cervical or breast ductal carcinoma in situ within the last 5 years.
• Subject has known sensitivity to any of the products to be administered during dosing.
• Subject likely to not be available to complete all protocol-required study visits or procedures, and/or to comply with all required study procedures (eg, electronic patient diary [ediary]) to the best of the subject and investigator's knowledge
• History or evidence of any other clinically significant disorder, condition or disease (with the exception of those outlined above) that, in the opinion of the investigator or Amgen physician, if consulted, would pose a risk to subject safety or interfere with the study evaluation, procedures, or completion.
• Subject previously has entered this study.
• If sexually active, subject is not willing to use acceptable contraception during treatment and for at least 9 days after the end of treatment.
• Subject is pregnant or breast feeding, or planning to become pregnant during the study or within 9 days after the end of treatment
• History of congenital long QT syndrome, second or third degree heart block, ventricular tachyarrythmias, or other conditions associated with prolonged QT interval
• A new onset of seizures or worsening of pre-existing seizure disorder

All Subjects with > 14 days between the last study visit in Study 20130356 or Study 20110100 and the screening visit in Study 20140159 will have the following exclusion criteria applied during screening and day 1:

• Unstable chronic heart failure defined as worsening pulmonary edema or other signs and symptoms as per investigator assessment during screening
• Received therapy with commercial cinacalcet after the last study visit in Study 20130356 or Study 20110100 before day 1 of Study 20140159
• Scheduled date for kidney transplantation from a known living donor that makes completion of the study unlikely
• Either new or recurrent cardiac ventricular arrhythmias requiring a change in treatment within 10 days prior to screening visit or day 1 of Study 20140159 screening
• Hepatic impairment indicated by elevated levels of hepatic transaminase or bilirubin (aspartate aminotransferase [AST] ≥ 1.5 × upper limit of normal [ULN] OR alanine aminotransferase [ALT] ≥ 1.5 × ULN OR total bilirubin ≥ 1 × ULN per institutional laboratory range) during screening

All Subjects - Day 1 Study Visit:

• Subject has an ongoing adverse event from Studies 20130356 or 20110100 that is considered related to investigational product and is ≥ Common Terminology Criteria for Adverse Events (CTCAE) (v 4.0) grade 3, and/or considered clinically significant in the opinion of the investigator
• Central laboratory values were not obtained/are not available at day 1 in Study 20140159
• 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, CYP3A4 inhibitors (eg, erythromycin, clarithromycin, ketoconazole, itraconazole), or CYP2D6 substrates (eg, flecainide, propafenone, metoprolol, desipramine, nortriptyline, clomipramine)
• Use of concomitant medications that may prolong the QTc interval (eg, ondansetron, albuterol)