Ferric citrate coordination complex (FCCC), a phosphate binder, may improve anemia and biochemical parameters in patients with advanced chronic kidney disease (CKD) before transition to dialysis.

Investigators led by Geoffrey A. Block, MD, of Reata Pharmaceuticals in Dallas, randomly assigned 203 patients with an estimated glomerular filtration rate (eGFR) less than 20 mL/min/1.73m2 to 2 tablets of FCCC per meal (210 mg ferric iron per tablet) or usual care for 9 months or until 3 months after starting dialysis. At baseline, mean hemoglobin (Hb) was higher than 8.0 g/dL and transferrin saturation (TSAT) less than 55%. At the nephrologists’ discretion, usual care patients could receive phosphate binders other than FCCC, erythropoiesis-stimulating agents (ESAs), blood transfusion, active vitamin D, and oral or intravenous iron.

FCCC therapy significantly increased Hb, TSAT, and serum ferritin, according to results published in the Journal of the American Society of Nephrology. During the study period, epoetin alfa was required by 8 FCCC vs 10 usual care patients, who received a higher weekly dose. Intravenous iron was given to 4 vs 11, respectively.

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“Our results in this high-risk population suggest that a simple, fixed-dose intervention may attenuate the decline in hemoglobin before initiation of dialysis and may reduce the need for ‘rescue’ with ESAs, intravenous iron, or blood transfusion,” Dr Block and his colleagues stated.

Intact fibroblast growth factor 23 (FGF23) held steady in FCCC patients but increased in usual-care patients. In addition, more FCCC than usual-care patients had serum phosphate within target range: 70% vs 45%, respectively.

“Our results demonstrate that fixed-dose FCCC maintained serum P concentrations within, or just above, the population reference range and abrogated the rise in FGF23 in the large majority of patients, despite very low eGFR,” Dr Block’s team pointed out.

Roughly a quarter of FCCC patients initiated dialysis compared with half of usual-care patients. The FCCC group experienced fewer hospital admissions, days in the hospital, and a lower incidence of a composite end point of provision of dialysis, transplantation, or death. More usual-care than FCCC patients had diabetes and peripheral vascular disease, so these particular findings should be viewed cautiously and not attributed solely to FCCC.

As expected, gastrointestinal events were common among FCCC patients, but not serious.

The study was funded by Keryx Biopharmaceuticals, Inc., the makers of FCCC.

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Block GA, Block MS, Smits G, et al. A pilot randomized trial of ferric citrate coordination complex for the treatment of advanced CKD. J Am Soc Nephrol. doi:10.1681/ASN.2018101016