Randomized controlled trial to compare the efficacy and safety of oral paricalcitol with oral calcitriol in dialysis patients with secondary hyperparathyroidism

Aim The objective of the study was to compare the efficacy and safety of oral paricalcitol with oral calcitriol for treating secondary hyperparathyroidism. Methods We conducted the first multicenter open-labelled parallel group randomized controlled trial in 66 patients on dialysis. Patients were randomized to paricalcitol or calcitriol at a 3:1 dose ratio and adjusted to maintain intact parathyroid hormone (iPTH) level between 150300pg/mL, serum calcium 2.74mmol/L and calcium-phosphate product 5.63mmol2/L2. The primary end point was the proportion of patients who achieved >30% reduction in iPTH. Results At 24 weeks, 22 (61.1%) patients in the paricalcitol and 22 (73.3%) in the calcitriol group had achieved the primary end-point (P-value=0.29). The cumulative proportion of patients who achieved the end-point at 6 weeks, 12 weeks and 24 weeks were 50%, 80.6% and 86.1%, respectively, in paricalcitol and 53.3%, 86.7% and 86.7%, respectively, in the calcitriol group (P-value=0.67). Median time to the end-point was 6 weeks in both groups. There were no significant differences in iPTH level at any time during the study. The median reduction in iPTH at 24 weeks was 48.4% in the paricalcitol group and 41.9% in the calcitriol group (P-value=0.6). The median maximal iPTH reduction was 77.1% (paricalcitol) and 83.7% (calcitriol), P-value=0.3. Serum calcium and incidence of hypercalcaemia did not differ between groups. 16.7% of patients in both groups had at least one episode of hypercalcaemia (serum calcium >2.74mmol/L). Other adverse events were similar between groups. Conclusion Our study suggests that oral paricalcitol has similar efficacy and safety to oral calcitriol.