Impact of Vitamin D Dose on Biochemical Parameters in Patients with Secondary Hyperparathyroidism Receiving Cinacalcet

Background/Aims: The calcimimetic cinacalcet (Mimpara®/Sensipar®) simultaneously lowers parathyroid hormone (PTH), phosphorus (P) and calcium (Ca) levels in patients with secondary hyperparathyroidism. The OPTIMA study demonstrated that cinacalcet and adjusted doses of vitamin D maximized control of these parameters. This post-hoc analysis of OPTIMA data assessed the impact of reducing or increasing the dose of concomitant vitamin D on PTH, P and Ca in patients receiving cinacalcet. Methods: Dialysis patients with mean baseline intact PTH (iPTH) 300–800 pg/ml (31.8–84.8 pM) received doses of cinacalcet titrated to achieve an iPTH of 150–300 pg/ml (15.9–31.8 pM). The dose of vitamin D could then be decreased to further reduce serum P or Ca, or increased/initiated to further decrease PTH levels if iPTH >300 pg/ml or to increase Ca if Ca