Cinacalcet in Paediatric Secondary Hyperparathyroidism (SHPT) Due to Chronic Kidney Disease (CKD)

Twelve-month, Multicenter, Intra-subject Controlled (Retrospective-prospective), Open-label, Active-treatment Study to Evaluate the Efficacy, Safety, Tolerability and Pharmacokinetics (PK) of Cinacalcet Hydrochloride for the Treatment of Secondary Hyperparathyroidism (SHPT) in Paediatric Subjects With Chronic Kidney Disease (CKD) on Dialysis, Followed by 12-month Study Extension.

Twelve-month, multicenter, intra-subject controlled (retrospective-prospective), open-label, active-treatment study to evaluate the dose-response and pharmacokinetics (PK) of cinacalcet HCl for the treatment of Secondary Hyperparathyroidism (SHPT) in paediatric subjects with chronic kidney disease (CKD) on dialysis, followed by 12-month study extension.

This multicenter, intra-subject controlled, open-label, active-treatment study will assess in children affected by Secondary Hyperparathyroidism, aged 2-18 years on chronic dialysis not responsive to standard of care (SoC) therapy, the response after 6-month cinacalcet compared intra-subject to SoC alone at screening visit 6 months prior to cinacalcet start. Secondary objectives are to evaluate effects on growth over 18 months and PK profile. At baseline children have PTH levels>300 pg/mL, plasma P<6 mg/dL, and Ca 8.4-10.5 mg/dL, or Ca x P product>60 not responsive to SoC. Initial dosing of cinacalcet will be 0.5-0.75 mg/Kg per os OD to be adjusted up to a max of 180mg OD for target PTH values<180 pg/mL in absence of hypocalcemia. Thirty children will be enrolled at 12 centres participating in a national paediatric dialysis registry, corresponding to an α=0.05 and a power of 80% using the McNemar test, with an expected % of responders to cinacalcet or SoC of 40% or 5% respectively, with a drop-out rate of 15. Primary study endpoint (EP) will be the % of children who will have a reduction from baseline >25% in mean PTH levels during the 6-mo efficacy-assessment period. Among secondary EPs over 18 mos will be the % of patients with mean PTH levels<300 pg/mL; the % change in PTH, Ca, P values, and the Ca x P product; PK profile (or population profile by age) and its correlation with PTH and testosterone levels; auxological indices and growth velocity; % of children with treatment-emergent adverse events and lab abnormalities; retention on treatment and reasons of treatment withdrawal. The study will evaluate whether cinacalcet represents a safe and effective therapeutic option for SHPT children.

Inclusion Criteria:

• Parents'/guardian written informed consent, and child's assent
• Age > 2 and <18 years;
• A dry body weight (BW) >10.49 Kg in males and >9.95 Kg in females, respectively;
• Inpatient or outpatient status at the time of enrolment;
• Males or females. Female subjects sexually active must be neither pregnant nor breastfeeding, and must lack childbearing potential from screening visit to the end of the safety follow-up
• On stable hemodialysis (HD) or peritoneal dialysis (PD) for their CKD for at least one month before entering the 6-month pre-treatment period;
• Plasma iPTH levels > 300 pg/mL, AND
• Plasma Ca levels > 9.4 mg/dL (with normal serum albumin level), AND
• Plasma P levels <6.5 mg/dL in patients younger than 6 years, or <6.0mg/dL in older patients, OR
• Ca x P product > 60;
• Records' availability for the following parameters 6 months prior to study entry: demographic information, physical examination, height and dry weight, auxological/anthropometric indices, blood pressure values, Kt/V urea, plasma iPTH, calcium, phosphorus, and alkaline phosphatise levels, blood pH and bicarbonate, serum creatinine/urea, C reactive protein (CRP) levels, liver function tests, blood count, blood 25(OH) vitamin D3 level.

Exclusion Criteria:

• The following laboratory values: Hb<9.0 g/dL, WBC<2000/mm3 (2x109/L), platelets <150,000/mm3 (150x109/L) only in subjects who are otherwise eligible for PK/PD assessments; abnormal liver function, defined by a total bilirubin ≥2 times the upper limit of normal values, ASAT, ALAT, γ-GT levels ≥2 times the ULN values.
• Any other lab values that in the opinion of the investigator might place the subject at unacceptable risk for participation in the study.
• History of malignancy (active malignancy, or off therapy since less than 1 year)
• History of diseases causing hypercalcemia
• Chronic inflammatory diseases (C-Reactive Protein-CRP >2 times the upper limit of normal values) requiring a concomitant corticosteroid or immunosuppressive therapy
• History of infectious diseases (including opportunistic infections) within 4 weeks prior to study entry
• Evidence as assessed by the Investigator of active or latent bacterial, viral or fungal infections at the time of potential enrollment, including subjects with evidence of HIV infection.
• Hepatitis-B surface antigen-positive subjects only in subjects who are otherwise eligible for PK/PD assessments
• Hepatitis C antibody-positive subjects who are also PCR-positive or RIBA positive only in subjects who are otherwise eligible for PK/PD assessments
• Use of recombinant human growth hormone therapy
• Use of drugs that interact with cinacalcet disposition
• Previous use of cinacalcet