Preliminary experience with cinacalcet use in persistent secondary hyperparathyroidism after kidney transplantation

Background. There is limited experience with the use of cinacalcet in the treatment of persistent secondary hyperparathyroidism after kidney transplantation. Methods. We retrospectively analyzed our experience in 18 renal allograft recipients who initiated cinacalcet therapy from I month to 23 years (median 3 years) posttransplantation and were maintained on the drug for 6 months. The daily dose was titrated from 30 mg up to a maximum of 180 mg to achieve a reduction in serum intact parathyroid hormone (PTH) levels. Results. Sustainable, significant decreases in mean calcium and alkaline phosphatase were noted at I month and intact PTH by 3 months, with 50% of patients achieving at least a 30% drop in PTH levels at 6 months. Serum phosphorous increased at 6 months, whereas urine N-telopeptides decreased. There were no significant changes in serum osteocalcin, albumin, and hemoglobin levels. We did not observe a tachyphylaxis phenomenon. Two patients reported occasional nausea, but did not require medication discontinuation. Estimated glomerular filtration rate did decrease progressively over the 6-month period. Conclusion. Cinacalcet appears to be an effective drug for the treatment of posttransplant hypercalcemia due to persistent secondary hyperparathyroidism. Further studies with more patients and longer follow-up will be needed to better elucidate the efficacy/safety profile for this agent, particularly with regard to long-term bone histology and renal outcomes.