Abstract

This study was carried out to evaluate the efficacy and safety of doxercalciferol as therapy for secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) stage 4 in a prospective clinical trial. A total of 35 CKD-4 patients who had a baseline parathyroid hormone (iPTH) >150 pg/mL and had not received any vitamin D analog in the preceding 8 weeks were followed up at intervals of 6 weeks for 18 weeks on oral therapy with doxercalciferol. The starting dose was 1.5 μg/day, and the dose was increased in steps of 1 μg/day if iPTH did not decrease by at least 30% on the subsequent visit. Doxercalciferol was stopped temporarily if low iPTH (<70 pg/mL), hypercalcemia (>10.7 mg/dL), or severe hyperphosphatemia (>8.0 mg/dL) occurred, and was restarted at a lower dose on reversal of these abnormalities. Calcium acetate was the only phosphate binder used. Mean iPTH decreased by 35.4 ± 4.4% from 381.7 ± 31.3 pg/mL to 237.9 ± 25.7 pg/mL (P < 0.001). The proportion of patients who achieved 30% and 50% suppression of iPTH levels was 83% and 72%, respectively. Mean serum calcium, phosphorus, and calcium-phosphorus product values did not differ significantly from the baseline values. Four, two, and nine patients developed hypercalcemia, severe hyperphosphatemia, and high CaxP (>55), respectively. Almost all patients recovered to an acceptable level within 2 weeks of stopping doxercalciferol and adjusting the phosphate binder dose. In all, 21 patients required temporary stoppage of therapy. Most of them were restarted on therapy at a reduced dose during the study. It can, therefore, be concluded that doxercalciferol is effective in controlling SHPT in CKD-4 patients with an acceptable risk of hyperphosphatemia and hypercalcemia.