No clinically relevant changes in vitamin d concentrations with PA21, A novel iron-based phosphate binder, over 52 weeks

A randomized, open-label, Phase 3 study evaluated PA21, a polynuclear iron(III)-oxyhydroxide phosphate binder, vs sevelamer carbonate (SEV), in dialysis patients with hyperphosphatemia. 1059 patients were randomized to PA21 (1.0-3.0 g/day; n=710) or SEV (2.4-14.4 g/day; n=349) for 12 weeks' dose titration followed by 12 weeks' maintenance. Eligible patients were enrolled in a 28-week safety extension study. 549 patients completed the extension study. Changes in serum concentrations of 25(OH)D, 1, 25(OH)2D, iPTH and total calcium (baseline to Week 52) for completers are shown (Table). In summary, mean serum concentrations of 25(OH)D increased with PA21 and decreased with SEV; changes were significantly different between treatment groups. No clinically relevant change in either group was seen in 1, 25(OH)2D or total calcium concentrations at Week 52. A greater increase in iPTH was seen with SEV vs PA21.