Abstract 1938

Calcitriol oral pulse therapy has been suggested as treatment of choice for secondary hyperparathyroidism, but its efficacy on iPTH and possible disadvantages (antiproliferative effect of high-dose calcitriol on growth cartilage) are still debated. The present study compares, in a one-year multicenter, prospective, open label, randomized trial, the effects of daily vs. intermittent (twice a week) calcitriol on suppression of iPTH levels. 85 patients were enrolled into the study. Here we analyse the effects of the first eight weeks of treatment with calcitriol on renal function (creatinine clearance), serum calcium and phosphate levels, iPTH suppression and alkaline phosphatase values (these parameters were measured 24 h after the calcitriol administration). The weekly dose of calcitriol was maintained constant (70 ng/kg/week) and identical in the two arms of the study. Thirty-six children, 28 males, with a mean age of 8.3 ± 4.8 yrs, a Ccr of 22.8 ± 12.8 ml/min/1.73sqm and with a median iPTH of 238 pg/ml (range 78-1240) were studied. After a two-week wash-out period (no vit. D analogues), the two groups were not different as to baseline Ccr, Ca, P, iPTH and AP. Results are given as mean ± sd and median (range). *:p < 0.05 vs baseline and §:p < 0.01 vs Intermittent Calcitriol (Student t-test or Wilcoxon signed rank test). (Table) A reduction in iPTH, compared to baseline level, was observed in 16/20 and 8/16 of patients (p<0.01; ×2) in the Daily and Intermittent group, respectively. According to this analysis, daily oral calcitriol seems to be more efficacious in suppressing iPTH compared to an equal calcitriol dose given twice weekly.

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