For adult patients who do not meet indications to surgery, the calcimimetic cinacalcet is approved for primary hyperparathyroidism (HPT), decreasing calcium and parathyroid hormone (PTH) levels. This drug is largely used in adults, but may be a challenge in daily practice in children, because of the risk of hypocalcemia, increased QT interval and drug interactions. A few pediatric cases have highlighted its potential interest in children with HPT; the aim here is to report the French pediatric experience in this setting. 

Material and methods:

 We retrospectively analyzed data from 19 pediatric patients from 7 tertiary French centres who received cinacalcet for HPT. The results are presented as median (interquartile range).

Results:

 At a median age of 12.2(2.5–14.8) years, 19 patients received Cinacalcet for primary HPT (12 patients with inactive CaSRmutation, 1 patient with CD73 mutation, 1 patient with PHEX mutation, 1 patient with multiple endocrine neoplasia and 4 patients with primary HPT of unknown etiology). Cinacalcet was introduced at an estimated glomerular filtration rate (eGFR) of 123(120–131) mL/min/1.73 m², plasma calcium of 2.98 (2.87–3.10) mmol/L, age-standardized (z score) phosphate of -2.7(-3.2;-1.9), total ALP of 214(111-225)UI/L, 25-D of 42(22-46) nmol/L, and PTH of 59(42–80) ng/L. The starting daily dose of cinacalcet was 0.7(0.6–0.9) mg/kg, with a maximum dose of 1.0(0.9–1.3) mg/kg per day. With a follow-up of 2.3(1.3–4.3) years on cinacalcet therapy, PTH remained stable at 44(35–59) ng/L (p=NS), as did eGFR, 25-D, ALP and phosphate and urinary calcium levels. In contrast, plasma calcium levels significantly decreased to 2.73(2.58–2.90) mmol/L (p=0.03). Nephrocalcinosis was not reported but one patient displayed nephrolithiasis. Cinacalcet was withdrawn in one patient (no side effect was reported). 

Conclusions:

 These results suggest that off-label cinacalcet in pediatric HPT controls hypercalcemia without significant side effects.