Cinacalcet treatment decreases plasma fibroblast growth factor 23 concentration in haemodialysed patients with chronic kidney disease and secondary hyperparathyroidism.

OBJECTIVE

Recent clinical studies suggest that fibroblast growth factor 23 (FGF23) is important in the pathogenesis of calcium-phosphate abnormalities in patients with chronic kidney disease and that increased plasma FGF23 concentration is a cardiovascular risk factor in these patients. The aim of this prospective, single-arm, open-label clinical study was to assess the influence of 6-month cinacalcet treatment on plasma FGF23 concentration in haemodialysed patients with secondary hyperparathyroidism (sHPT).

DESIGN, PATIENTS AND MEASUREMENTS: In 58 haemodialysed patients with sHPT (parathormone PTH > 300 ng/l), serum PTH, FGF23, calcium and phosphate concentrations were assessed before the first dose of cinacalcet and after 3 and 6 months of treatment.

RESULTS

Serum PTH concentration decreased significantly after 3 and 6 months of treatment, and the mean serum calcium and phosphate concentrations remained stable during the treatment period. Plasma FGF23 concentration (geometric mean with 95% confidence index) decreased after 3 and 6 months of treatment from 354 (261-481) ng/l to 295 (204-428) ng/l; P = 0·099 and to 183 (117-285) ng/l; P = 0·015, respectively. FGF23 concentration decreased in 52% of patients. In multivariate regression analysis, plasma FGF23 concentration changes were explained by the changes in serum phosphate, but not by serum PTH or calcium changes or by the dose of cinacalcet.

CONCLUSIONS

1. Cinacalcet treatment decreases plasma FGF23 concentration in haemodialysed patients with secondary hyperparathyroidism. 2. The decrease in plasma FGF23 concentration seems to be related to the decrease in serum phosphate concentration.