Clinical issues regarding cinacalcet hydrochloride in Japan.
Currently available cinacalcet hydrochloride has a greater advantage over conventional vitamin D therapy, although the ability of cinacalcet to suppress parathyroid hormone (PTH) varies among individuals. This article deals with the clinical issues of cinacalcet. Studies examining the impact of cinacalcet on parathyroid gland cells showed that cinacalcet may cause changes in PTH secretion, reduce the parathyroid gland size, and alter parathyroid gland function, suggesting the possibility that use of cinacalcet can eventually be stopped. Combined cinacalcet and vitamin D can reportedly increase vitamin D receptor expression. In a double-blind, placebo-controlled randomized study involving 1184 previously untreated secondary hyperparathyroidism (SHPT) patients, cinacalcet significantly reduced the likelihood of hospitalization for parathyroidectomy, fractures, and cardiovascular disease. Fibrous osteitis was suppressed in the rat model of renal failure treated with cinacalcet. Considering that the drug price of cinacalcet is lower in Japan than in the USA and Europe, it is highly likely that cinacalcet will be used to suppress PTH in Japan.