| [ Summary ] |
The hexafluorinated vitamin D3 analog, falecalcitriol, is several times more potent than calcitriol in regulation of Ca metabolism and the immune system. The reason for this higher biological activity was attributed to several mechanisms, including higher activity of its 23(S)-hydroxylated metabolite [hexafluoro-1,23(S),25(OH)3D3], lower affinity of falecalcitriol to vitamin D binding protein, and higher affinity of falecalcitriol-receptor complexes to DNA. It was reported that administration of falecalcitriol to patients with secondary hyperparathyroidism, accompanied by chronic renal failure, showed effective suppression of serum PTH levels and bone turnover, without notable changes in serum Ca levels. Although falecalcitriol may be an effective new drug against secondary hyperparathyroidism, the difference in clinical efficacy between falecalcitriol and calcitriol or other active vitamin D3 analogs has not been fully investigated. Further research may provide useful information concerning the treatment of secondary hyperparathyroidism with these vitamin D3 analogs. |