Efficacy and side effects of intermittent intravenous and oral doxercalciferol (1 alpha-hydroxyvitamin D-2) in dialysis patients with secondary hyperparathyroidism: A sequential comparison

Most reports on the effectiveness and side effects of oral versus parentera l calcitriol or alfacalcidol in hemodialysis patients with secondary hyperp arathyroidism show no advantage of parenteral treatment. The efficacy and s afety of intravenous doxercalciferol (1 alphaD(2)) were studied in hemodial ysis patients with secondary hyperparathyroidism (plasma intact parathyroid hormone [iPTH]: range, 266 to 3,644 pg/mL; median, 707 pg/mL). These resul ts were compared with those of a previous trial using intermittent oral 1 a lphaD(2); the same 70 patients were entered onto both trials, and 64 patien ts completed both trials per protocol. Twelve weeks of open-label treatment in both trials were preceded by identical 8-week washout periods. Degrees of IPTH suppression from baseline were similar in the two trials, with iPTH level reductions less than 50% in 89% and 78% of patients during oral and intravenous treatment, respectively. Grouping patients according to entry I PTH levels (<750 and <greater than or equal to>750 pg/mL) showed similar bu t more rapid iPTH suppression in the low-iPTH groups, whereas longer treatm ent and larger doses were required by the high-iPTH groups. Highest serum c alcium levels averaged 9.82 +/- 0.14 and 9.67 +/- 0.11 mg/dL during oral an d intravenous 1 alphaD(2) treatment, respectively (P = not significant [NS] ), Prevalences of serum calcium levels greater than 11.2 mg/dL during oral and intravenous treatment were 3.62% and 0.86% of calcium measurements, res pectively (P < 0.001), Highest serum phosphorus levels during oral and intr avenous treatment averaged 5.82 +/- 0.21 and 5.60 +/- 0.21 mg/dL, respectiv ely (P = NS). The percentage of increments in serum phosphorus levels durin g oral treatment exceeded that during Intravenous treatment during 5 of 12 treatment weeks. Thus, intermittent oral and intravenous therapy with 1<alp ha>D-2 reduced iPTH levels effectively and similarly, hypercalcemia was les s frequent, and serum phosphorus levels increased less during Intravenous t han oral 1 alphaD(2) therapy, suggesting that intravenous 1 alphaD(2) thera py may be advantageous In patients prone to hypercalcemia or hyperphosphate mia. (C) 2001 by the National Kidney Foundation, Inc.