Paricalcitol Versus Calcitriol in the Treatment of Secondary Hyperparathyroidism

Kidney Int. 2003 Apr;63(4):1483-90. doi: 10.1046/j.1523-1755.2003.00878.x.

Abstract

Background: Management of secondary hyperparathyroidism has included the use of active vitamin D or vitamin D analogs for the suppression of parathyroid hormone (PTH) secretion. Although, these agents are effective, therapy is frequently limited by hypercalcemia, hyperphosphatemia, and/or elevations in the calcium-phosphorus (Ca x P) product. In clinical studies, paricalcitol was shown to be effective at reducing PTH concentrations without causing significant hypercalcemia or hyperphosphatemia as compared to placebo. A comparative study was undertaken in order to determine whether paricalcitol provides a therapeutic advantage to calcitriol.

Methods: A double-blind, randomized, multicenter study comparing the safety and effectiveness of intravenous paricalcitol and calcitriol in suppressing PTH concentrations in hemodialysis patients was performed. A total of 263 randomized patients were enrolled at domestic and international sites. Following the baseline period, patients with serum Ca x P < 75, and a PTH level > or =300 pg/mL were randomly assigned to receive either paricalcitol or calcitriol in a dose-escalating fashion for up to 32 weeks. Dose adjustments were based on laboratory results for PTH, calcium, and Ca x P. The primary end point was the greater than 50% reduction in baseline PTH. Secondary end points were the occurrence of hypercalcemia and elevated Ca x P product.

Results: Paricalcitol-treated patients achieved a > or =50% reduction from baseline PTH significantly faster than did the calcitriol-treated patients (P = 0.025) and achieved a mean reduction of PTH into a desired therapeutic range (100 to 300 pg/mL) at approximately week 18, whereas the calcitriol-treated patients, as a group, were unable to achieve this range. Moreover, paricalcitol-treated patients had significantly fewer sustained episodes of hypercalcemia and/or increased Ca x P product than calcitriol patients (P = 0.008).

Conclusion: Paricalcitol treatment reduced PTH concentrations more rapidly with fewer sustained episodes of hypercalcemia and increased Ca x P product than calcitriol therapy.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Calcitriol / administration & dosage*
  • Calcitriol / adverse effects
  • Calcium Channel Agonists / administration & dosage*
  • Calcium Channel Agonists / adverse effects
  • Ergocalciferols / administration & dosage*
  • Ergocalciferols / adverse effects
  • Female
  • Humans
  • Hypercalcemia / blood
  • Hypercalcemia / chemically induced
  • Hypercalcemia / epidemiology
  • Hyperparathyroidism, Secondary / blood
  • Hyperparathyroidism, Secondary / drug therapy*
  • Incidence
  • Male
  • Middle Aged
  • Parathyroid Hormone / blood

Substances

  • Calcium Channel Agonists
  • Ergocalciferols
  • Parathyroid Hormone
  • paricalcitol
  • Calcitriol