Impact of ferric citrate, an oral phosphate binder, on mineral and bone metabolism markers in dialysis patients

Abstract

Background: We conducted a multicenter, international, randomized, open-label clinical trial of a novel phosphate binder. Methods: 441 dialysis subjects were enrolled in a trial consisting of a two week washout period during which all binders were stopped and a 52 week Safety Assessment Period (SAP) in which participants were randomized 2:1 to ferric citrate (FC, 1 gram caplets) or active control (AC), followed by a one month effi cacy assessment period. There were 292 participants randomized to FC and 149 to AC. The AC group consisted of 78 participants treated with sevelamer carbonate, 41 with calcium acetate, and 30 with a combination of these agents. Results: Results for mean serum phosphorus, calcium, iPTH and aluminum postwashout and at the completion of the SAP are in the table. Throughout the study, between 51% and 61% of participants had phosphorus in the 3.5 to 5.5 mg/dL range, without signifi cant between group differences (p=0.41 to 0.98 at various time points). Four participants in the AC group had serum calcium greater than 10.5mg/dL, necessitating discontinuation of AC therapy versus none in the FC group; specifi cally, calcium was lower in FC subjects compared to calcium acetate only (9.1±0.9 vs 9.5±1.0, p=0.008). Conclusions: Traditional markers of bone and mineral metabolism were similar in the AC and FC groups over a 52 week safety assessment period, with overall low aluminum levels in both groups despite the citrate component of FC and as expected given the use of calcium-containing binders, several episodes of hypercalcemia in the AC group. We conclude that FC can achieve control of MBD parameters comparable to current usual care.