83805-11-2

Hexafluorinated analog of Calcitriol (C144500). A more potent therapeutic agent for secondary hyperparathyroidism.

A poison by ingestion.

Falecalcitriol, previously known as flocalcitrol, was launched by several codevelopers in Japan for the treatment of secondary hyperthyroidism (SHPT). This hexafluorinated analog of 1α,25-dihydroxyvitamin D3 (calcitriol), the hormonally active form of vitamin D3, can be obtained by several different synthetic routes from a conveniently protected cholestenol, a key step being an aldol reaction with hexafluoroacetone. Falecalcitriol is several times more active than 1,25(OH)₂D₃ in regulating the proliferation of parathyroid cells and parathyroid hormone (PTH) synthesis that are believed to be mediated through binding to VDR, a nuclear receptor for vitamin D; furthermore, it was proposed that a bioactive 23S-hydroxylated metabolite, resistant to further metabolism, contributes to the retention of an active compound for longer in cells and so, to significantly lengthen the duration of action. In a comparative clinical study conducted in hemodialysis patients with moderate to severe SHPT, falecalcitriol was found to be more active than alfacalcidol in suppressing parathyroid hormone without triggering hypercalcemia.

University of Wisconsin (US)

Hornel, Fulstan