Cinacalcet for the treatment of hypercalcemia in renal transplanted patients with secondary hyperparathyroidism

Persistent hyperparathyroidism is the most frequent cause of hypercalcemia after renal transplantation, namely, hypercalcemia is observed in about 10% of patients at 1 year. This prospective study evaluated the effect of cinacalcet, a second-generation calcimimetic, on serum calcium and parathyroid hormone (PTH) blood levels among recipients with hypercalcemia due to persistent hyperparathyroidism. Thirteen renal transplanted patients (10 women and 3 men) were included based upon: a total serum calcium >10.5 mg/dL; intact PTH (iPTH) blood levels >65 pg/mL; graft function >6 months, and stable maintenance immunosuppressive therapy. After inclusion, patients initially received 30 mg of cinacalcet once daily. The mean time of initiation was 64 +/- 7 months after transplantation. The follow-up was 6 months. The median dose of cinacalcet was 30 mg/d (5 patients received 60 mg/d). During the study period, renal function remained stable. Serum calcium levels decreased significantly from 11.7 +/- 0.39 to 10.35 +/- 0.8 mg/dL (P < .001). Serum phosphate levels increased from 2.82 +/- 0.34 mg/dL to 3.2 +/- 0.41 mg/dL (P < .05). The mean iPTH levels significantly decreased from 308 +/- 120 to 210 +/- 80 pg/mL (P < .05). There were no significant change in 25-hydroxyvitamin D3 blood levels (from 17.7 +/- 9 to 17.4 +/- 6 ng/mL), but the 1,25-dihydroxyvitamin D3 blood levels decreased from 53.8 +/- 18.2 to 32.6 +/- 9.2 pg/mL (P < .01). There were no significant changes in blood levels of alkaline phosphatase, magnesium, bicarbonate, calciuria, phosphaturia, and immunosuppressive drugs. Cinacalcet was well tolerated in all patients except one who had gastrointestinal discomfort. In summary, cinacalcet corrected hypercalcemia and improved phosphatemia in patients with persistent hyperparathyroidism after transplantation with no negative effects on renal function.