Long-Term Cinacalcet HCl Treatment Improved Bone Metabolism in Japanese Hemodialysis Patients with Secondary Hyperparathyroidism

Background/Aims: Few clinical trials conducted with cinacalcet have thoroughly addressed its effects of on bone metabolism. We assessed the effects of cinacalcet on bone markers in Japanese hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT). Methods: 200 Japanese HD patients with intact PTH (iPTH) levels ≥300 pg/ml were enrolled. The dose of cinacalcet was titrated from 25 up to 100 mg/day to achieve iPTH levels ≤250 pg/ml for 52 weeks. Results: At the end of the study visit, 57.8% of patients (115/199) had achieved iPTH levels ≤250 pg/ml. Serum Ca, phosphorus (P) and Ca × P levels decreased rapidly and were maintained throughout the study. At week 52, all bone metabolic markers levels had decreased significantly from baseline. Although bone resorption markers gradually decreased throughout the study period, bone alkaline phosphatase significantly increased during the first 4 weeks and then gradually decreased. Conclusions: The time courses of changes in bone markers after cinacalcet treatment resembled those observed after surgical parathyroidectomy (PTx), sometimes described as the hungry bone syndrome, indicating that cinacalcet treatment induces a rapid recovery in bone response to calcium. In addition, long-term efficacy and safety of cinacalcet were also observed in Japanese patients undertaking long-term hemodialysis (167.0 ± 81.4 months).