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Abstract
Based on research conducted so far, active vitamin D^sub 3^ is known to suppress the secretion of parathyroid hormone (PTH), which is stimulated by chronic renal failure. We investigated the effect and safety of falecalcitriol, a new type of active vitamin D^sub 3^, in patients with secondary hyperparathyroidism accompanied by chronic renal failure in a multicenter study. In a double-blind study, 121 patients were randomly assigned to a falecalcitriol group (63 patients) or a placebo group (58 patients). They received daily oral falecalcitriol or placebo for 8 weeks. The change rates of intact PTH (i-PTH) , midregion PTH (m-PTH), and carboxy-terminal PTH (c-PTH) were determined as major evaluation parameters. The falecalcitriol group showed a significant suppression (P < .01) of 34.8% in i-PTH; in contrast, the placebo group recorded a significant rise (P < .01) of 12.4%, with a significant difference (P < .01) between the groups. The results for m-PTH and c-PTH were similar to those for i-PTH. Serum calcium, meanwhile, rose significantly (P < .01) in the falecalcitriol group after 2 weeks. The mean values, however, remained within the normal range, and the change rate was within 10%. Apart from the rise in serum calcium, there were no differences in adverse reactions from the placebo group. The results suggest that falecalcitriol is an effective drug against secondary hyperparathyroidism with chronic renal failure because it significantly inhibits a rise in i-PTH under conditions that cause no large changes in serum calcium.[PUBLICATION ABSTRACT]