Clinical effects of maxacalcitol on secondary hyperparathyroidism of uremic patients.

Maxacalcitol (22-oxacalcitriol [OCT]) is a newly developed vitamin D analogue in Japan. OCT has shown less calcemic action and a strong suppressive effect on parathyroid hormone (PTH) in uremic rats and dogs. In uremic patients with secondary hyperparathyroidism, OCT dose-dependently suppressed PTH secretion and increased serum calcium levels. However, more than 60% of patients achieved a greater than 30% decrease in intact PTH level from baseline with long-term OCT treatment up to 1 year without an unphysiological increase in mean serum calcium levels. Long-term treatment also brought about a reduction in bone metabolic markers, including bone alkaline phosphatase, tartrate-resistant acid phosphatase, and bone gra-protein. These results suggest that although careful attention should be paid to the onset of hypercalcemia and oversuppression of PTH, OCT is one of the effective tools for the treatment of secondary hyperparathyroidism.