Long-Term Clinical Practice Experience with Cinacalcet for Treatment of Hypercalcemic Hyperparathyroidism after Kidney Transplantation

Abstract

Within this prospective, open-label, self-controlled study, we evaluated the long-term effects of the calcimimetic cinacalcet on calcium and phosphate homeostasis in 44 kidney transplant recipients (KTRs) with hypercalcemic hyperparathyroidism by comparing biochemical parameters of mineral metabolism between pre- and posttreatment periods. Results are described as mean differences (95% CIs) between pre- and posttreatment medians that summarize all repeated measurements of a parameter of interest between the date of initial hypercalcemia and cinacalcet initiation (median of 1.6 (IQR: 0.6–3.8) years) and up to four years after treatment start, respectively. Cinacalcet was initiated after 1.8 (0.8–4.7) years posttransplant and maintained for 6.2 (3.9–7.6) years. It significantly decreased total serum calcium (−0.30 (−0.34 to −0.26) mmol/L,P<0.001) and parathyroid hormone levels (−79 (−103 to −55) pg/mL,P<0.001). Serum levels of inorganic phosphate (Pi) and renal tubular reabsorption of phosphate to glomerular filtration rate (TmP/GFR) increased simultaneously (Pi: 0.19 (0.15–0.23) mmol/L,P<0.001, TmP/GFR: 0.20 (0.16–0.23) mmol/L,P<0.001). In summary, cinacalcet effectively controlled hypercalcemic hyperparathyroidism in KTRs in the long-term and increased low Pi levels without causing hyperphosphatemia, pointing towards a novel indication for the use of cinacalcet in KTRs.