Is it safe to discontinue Auryxia (Ferric Citrate) in an End-Stage Renal Disease (ESRD) patient already on sevelamer due to formulary and cost issues?

Discontinuing Auryxia (Ferric Citrate) in ESRD Patients on Sevelamer

Yes, it is safe to discontinue Auryxia (ferric citrate) in your ESRD patient already on sevelamer, but you must carefully monitor iron parameters and potentially adjust IV iron therapy, as ferric citrate provides significant systemic iron absorption that will be lost upon discontinuation. 1, 2

Key Safety Considerations

Iron Absorption from Ferric Citrate

• Ferric citrate causes significant systemic iron absorption through disrupted intestinal tight junctions in uremic patients, which can bypass normal physiological regulation of iron absorption. 1, 2
• The FDA specifically warns that this absorption mechanism may lead to iron overload and recommends careful monitoring of iron stores in dialysis patients on ferric citrate. 1, 2
• Upon discontinuation, you will lose this iron source, which may have been reducing or eliminating the patient's IV iron requirements. 3, 4

Expected Changes After Discontinuation

Iron and ESA Requirements:

• Clinical trial data shows ferric citrate reduces IV iron usage by approximately 1,960 mg per patient per year and ESA usage by 129,106 units per patient per year. 3
• After switching from ferric citrate to other phosphate binders, expect to increase IV iron by approximately 33% and ESA doses by approximately 8%. 4
• Monitor ferritin and transferrin saturation (TSAT) at least every 3 months after discontinuation. 2

Phosphate Control:

• Sevelamer carbonate provides equivalent phosphate control to ferric citrate, so hyperphosphatemia should not worsen if the sevelamer dose is adequate. 5, 6
• Ensure the patient's current sevelamer dose is optimized to maintain serum phosphorus in target range (typically <5.5 mg/dL). 1

Monitoring Plan After Discontinuation

Within 2-4 Weeks:

• Check serum phosphorus to ensure adequate control with sevelamer alone. 5
• Assess for signs of iron deficiency (fatigue, decreased exercise tolerance). 1

Within 1-3 Months:

• Check ferritin and TSAT to determine if IV iron supplementation is needed. 2
• Monitor hemoglobin and adjust ESA dosing as needed. 3
• Target conservative ferritin levels (<500 ng/mL) to avoid iron overload from IV iron. 2

Cost-Benefit Considerations

• While ferric citrate is expensive, discontinuing it will likely increase costs for IV iron and ESAs, potentially offsetting some savings. 3, 4
• The managed care cost-offset model suggests ferric citrate may actually reduce total dialysis costs by $80,214 per 500 ESRD patients monthly when accounting for reduced IV iron and ESA usage. 4
• However, if formulary restrictions make ferric citrate unavailable, sevelamer remains an effective and safe alternative for phosphate binding. 1

Alternative Considerations

If iron supplementation becomes necessary:

• Avoid excessive IV iron administration, which is associated with increased cardiovascular events and mortality in hemodialysis patients. 1, 2
• Consider the Japanese approach of maintaining lower ferritin targets (280-320 ng/mL) with minimal IV iron use, which is associated with better overall survival. 1, 2
• Oral iron supplementation (200 mg elemental iron daily in divided doses) may be attempted, though absorption is limited in ESRD patients. 1

Common Pitfalls to Avoid

• Do not assume the patient's current iron stores will remain stable after discontinuing ferric citrate—the systemic iron absorption from ferric citrate is substantial and will be lost. 1, 2
• Do not aggressively replace with IV iron without monitoring—this can lead to iatrogenic iron overload, which is increasingly recognized as harmful in dialysis patients. 1, 2
• Do not forget to reassess sevelamer dosing—while phosphate control should remain adequate, individual dose adjustments may be needed. 5, 6