Cinacalcet de novo in persistent hypercalcemia after kidney transplantation secondary to hyperparathyroidism: long-term follow-up and effect of withdrawal.

BACKGROUND: Secondary hyperparathyroidism that persists after kidney transplantation (KT), is the main cause of hypercalcemia. Cinacalcet has been used to control hypercalcemia in KT patients.
OBJECTIVE: The aim of this study was to evaluate the effect of de novo cinacalcet in KT patients with hypercalcemia and the evolution after its withdrawal.
METHODS: This observational study included 41 KT patients (17 men) with persistent hypercalcemia (>6 months), defined as serum calcium (sCa) ≥10.5 mg/dL, and a mean age of 51.1 ± 13.3 years with a functional allograft for >12 months. The time after surgery to begin cinacalcet was 33 months (range, 12.5-81.3). The initial dose of cinacalcet was 30 mg/d. In a subgroup of 14 patients cinacalcet was stopped after 1 year. We studied the evolution of serum levels of calcium, phosphorus, intact pathyroid hormone (iPTH), and serum creatinine.
RESULTS: Calcemia normalized in all patients (sCa <10.2 mg/dL). iPTH decreased (basal 267 ± 212 pg/mL vs final: 219 ± 160 pg/mL; P = ns) Serum phosphorus increased (basal 2.85 ± 0.48 mg/dL vs final 3.16 ± 0.50 mg/dL; P = ns). Renal function remained stable (basal creatinine 1.49 ± 0.48 vs final 1.47 ± 0.32 mg/dL; P = ns). After stopping cinacalcet, in group 1 calcemia persisted at normal levels in 50% (n = 7), but the drug had to be reintroduced in the other 50% after 10 ± 7.9 months. No adverse events were documented.
CONCLUSIONS: Cinacalcet is an effective alternative for the treatment of hypercalcemia in patients with persistent hyperparathyroidism after KT. Once the treatment is started, there is presently no invice to disclose to who tolerate its withdrawal or the time to do so.