Mechanism of action of AURYXIA

Watch this video and learn how the unique formulation of AURYXIA works in the body to help manage adult patients’ phosphorus levels.1,2

Chronic kidney disease, CKD, is characterized by a gradual loss of kidney function.3 The kidneys play an important role in regulating the amount of phosphorus in blood, removing excess phosphorus for renal excretion.3,4 Loss of kidney function in end stage renal disease diminishes the kidney’s ability to control serum phosphate levels, causing hyperphosphatemia.4

AURYXIA is a unique formulation of ferric citrate coordination complexes indicated for the control of serum phosphorus levels in adults with CKD receiving dialysis.1,2,5 AURYXIA is an iron-based, calcium-free, non-chewable phosphate binder, which after swallowing reaches the gastrointestinal tract where ferric iron binds to dietary phosphates to produce ferric phosphate, an insoluble compound that is readily excreted in fecal matter.1,2,6-8 By lowering gastrointestinal phosphate absorption, AURYXIA reduces serum phosphorus concentrations in patients with CKD receiving dialysis.1,2,6-8

How AURYXIA lowers phosphate levels

AURYXIA is a unique formulation of ferric citrate coordination complexes for control of serum phosphorus levels in adults with CKD receiving dialysis.1,2,5

Ferric iron binds to dietary phosphate in the GI tract to produce ferric phosphate1

This compound is insoluble and is readily excreted in the stool1


By lowering gastrointestinal phosphate absorption, AURYXIA reduces serum phosphorus concentrations1

CKD=chronic kidney disease.

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See how AURYXIA helped patients reach their target goals

AURYXIA helped patients reach and stay in the range of 3.5-5.5 mg/dL during a 56-week trial.1
Patients had a mean serum phosphorus level of 7.41 mg/dL at baseline and 4.88 mg/dL at Week 56.9


See trial design

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Trial design1,10

A multicenter, randomized, open‐label trial evaluated the ability of AURYXIA to lower serum phosphorus in patients with CKD on dialysis over 56 weeks. Eligible patients had serum ferritin <1000 ng/mL, serum TSAT <50%, and serum phosphorus ≥2.5 and ≤8.0 mg/dL at the screening visit. The safety and efficacy of AURYXIA were studied in the 52‐week active‐controlled period (AURYXIA n=292, Active Control n=149), then AURYXIA patients were re‐randomized to either continue AURYXIA treatment or receive placebo during the placebo‐controlled period, weeks 52‐56 (AURYXIA n=96, placebo n=96). The primary endpoint was the change in serum phosphorus from baseline (Week 52) to Week 56 between AURYXIA and placebo. The key secondary endpoint was the change in serum phosphorus from baseline (Week 0) to Week 52 between AURYXIA and Active Control.

TSAT=transferrin saturation; Active Control=sevelamer carbonate and/or calcium acetate.



AURYXIA® (ferric citrate) is contraindicated in patients with iron overload syndromes, e.g., hemochromatosis


  • Iron Overload: Increases in serum ferritin and transferrin saturation (TSAT) were observed in clinical trials with AURYXIA in patients with chronic kidney disease (CKD) on dialysis treated for hyperphosphatemia, which may lead to excessive elevations in iron stores. Assess iron parameters prior to initiating AURYXIA and monitor while on therapy. Patients receiving concomitant intravenous (IV) iron may require a reduction in dose or discontinuation of IV iron therapy
  • Risk of Overdosage in Children Due to Accidental Ingestion: Accidental ingestion and resulting overdose of iron-containing products is a leading cause of fatal poisoning in children under 6 years of age. Advise patients of the risks to children and to keep AURYXIA out of the reach of children


The most common adverse reactions reported with AURYXIA in clinical trials were:

  • Diarrhea (21%), discolored feces (19%), nausea (11%), constipation (8%), vomiting (7%) and cough (6%)


  • Pregnancy and Lactation: There are no available data on AURYXIA use in pregnant women to inform a drug-associated risk of major birth defects and miscarriage. However, an overdose of iron in pregnant women may carry a risk for spontaneous abortion, gestational diabetes and fetal malformation. Data from rat studies have shown the transfer of iron into milk, hence, there is a possibility of infant exposure when AURYXIA is administered to a nursing woman


When clinically significant drug interactions are expected, e.g., Ciprofloxacin or Doxycycline, separate timing of administration.


AURYXIA® (ferric citrate) is indicated for the control of serum phosphorus levels in adult patients with chronic kidney disease on dialysis

To report suspected adverse reactions, contact Akebia Therapeutics, Inc. at 1-844-445-3799

Please see full Prescribing Information


  1. AURYXIA® [Package Insert]. Cambridge, MA: Akebia Therapeutics, Inc.
  2. Ganz T, Bino A, Salusky IB. Mechanism of action and clinical attributes of AURYXIA® (Ferric Citrate). Drugs. 2019;79(9):957-968. doi:10.1007/s40265-019-01125-w
  3. Webster AC, Nagler EV, Morton RL, Masson P. Chronic kidney disease. Lancet. 2017;389(10075):1238-1252. doi:10.1016/S0140-6736(16)32064-5
  4. Hruska KA, Mathew S, Lund R, Qiu P, Pratt R. Hyperphosphatemia of chronic kidney disease. Kidney Int. 2008;74(2):148-157. doi:10.1038/ki.2008.130
  5. Pergola PE, Fishbane S, Ganz T. Novel oral iron therapies for iron deficiency anemia in chronic kidney disease. Adv Chronic Kidney Dis. 2019;26(4):272-291. doi:10.1053/j.ackd.2019.05.002
  6. Yagil Y, Fadem SZ, Kant KS, et al. Managing hyperphosphatemia in patients with chronic kidney disease on dialysis with ferric citrate: latest evidence and clinical usefulness. Ther Adv Chronic Dis. 2015;6(5):252-263. doi:10.1177/2040622315589934
  7. Pennoyer A, Bridgeman MB. Ferric citrate (AURYXIA) for the treatment of hyperphosphatemia. P T. 2015;40(5):329-339.
  8. Iida A, Kemmochi Y, Kakimoto K, et al. Ferric citrate hydrate, a new phosphate binder, prevents the complications of secondary hyperparathyroidism and vascular calcification. Am J Nephrol. 2013;37(4):346-358. doi:10.1159/000348805
  9. Data on File 1, Akebia Therapeutics, Inc.
  10. Umanath K, Sika M, Niecestro R, et al; Collaborative Study Group. Rationale and study design of a three period, 58-week trial of ferric citrate as a phosphate binder in patients with ESRD on dialysis. Hemodial Int. 2013;17(1):67-74. doi:10.1111/j.1542-4758.2012.00711.x