An Open, Randomized, Crossover Phase 2 Pilot Study of Treatment of Stage 3B Renal Failure With Active Vitamin D or a Phosphate Binder to Evaluate the Effect on the FGF23 and PTH Levels.

Patients with reduced renal function normally develop hyperparathyroidism, which in turn is associated with increased cardiovascular risk and de-calcification. Hyperparathyroidism may be enhanced by an increased level of FGF23 which is often seen in the early stage of renal failure. This pilot study will investigate the FGF23-lowering effect of early initiation of treatment with a phosphate binder versus active vitamin D in an open crossover design.