How much does ferrous carboxymaltose (intravenous iron formulation) increase ferritin storage?

Ferric Carboxymaltose Ferritin Storage Increase

Ferric carboxymaltose increases ferritin storage by approximately 218-735 ng/mL depending on the clinical population and cumulative dose administered, with the most robust data showing mean increases of 264 ng/mL in iron-deficient anemia patients and 735 ng/mL in chronic kidney disease patients after cumulative doses of 1,000-1,500 mg. 1

Magnitude of Ferritin Increase by Clinical Population

Iron Deficiency Anemia (General Population)

• Mean ferritin increase of 264.2 ± 224.2 ng/mL in patients intolerant to oral iron (Cohort 1) at Day 35 after cumulative doses up to 1,500 mg 1
• Mean ferritin increase of 218.2 ± 211.4 ng/mL in patients with unsatisfactory response to oral iron (Cohort 2) at Day 35 1
• These increases occurred from baseline ferritin levels that were already in the "sufficient" range (321-460 ng/mL), demonstrating robust storage replenishment 2

Chronic Kidney Disease (Non-Dialysis Dependent)

• Mean ferritin increase of 734.7 ± 337.8 ng/mL prior to Day 56 after ferric carboxymaltose administration 1
• This represents the highest magnitude of ferritin increase documented across clinical populations 1
• Baseline ferritin in this population was approximately 100-300 ng/mL 3

Cancer-Related Anemia

• Mean ferritin increase of 1,200 ng/mL from baseline of 190 ng/mL after 1,100 mg cumulative dose over 16 weeks 2
• Mean ferritin increase of 1,265.5 ng/mL from baseline of 460.5 ng/mL after 937.5 mg cumulative dose 2
• These dramatic increases occurred in patients receiving concurrent erythropoiesis-stimulating agents 2

Heart Failure with Iron Deficiency

• Mean ferritin increase of 269 ng/mL (95% CI: 229-309) from baseline to Week 24 in the CONFIRM-HF trial 1
• Baseline ferritin was 57 ng/mL in this population, representing true iron deficiency 1

Dose-Response Relationship

Standard Dosing Regimen

• Maximum single dose of 1,000 mg iron administered over minimum 15 minutes 2, 1
• Typical cumulative dose of 1,000-1,500 mg given as two doses separated by at least 7 days 1
• The ferritin response is dose-dependent, with higher cumulative doses producing greater storage replenishment 4

Time Course of Ferritin Elevation

• Ferritin levels increase markedly and rapidly following IV ferric carboxymaltose administration 2
• Peak ferritin elevation occurs within the first 4 weeks post-administration 2
• Critical monitoring caveat: Ferritin cannot be used as an accurate indicator of iron status within 4 weeks of IV iron administration due to acute-phase reactant effects 2

Clinical Context and Practical Implications

When to Reassess Iron Status

• Re-evaluate iron parameters (ferritin and TSAT) 3 months after initial treatment, not earlier 2, 5, 6
• Early re-evaluation within 4 weeks should be avoided as ferritin levels are artificially elevated and unreliable 2, 6
• For chronic conditions like heart failure, consider routine iron status evaluation 1-2 times per year 2, 6

Transferrin Saturation Changes

• Ferric carboxymaltose also increases transferrin saturation by 13-30% depending on population 1
• In iron deficiency anemia patients: TSAT increased by 13-20% 1
• In chronic kidney disease patients: TSAT increased by 30% 1

Hemoglobin Response Correlation

• The ferritin increase correlates with hemoglobin improvements of 0.6-2.9 g/dL depending on baseline severity and clinical condition 1
• A single dose of 1,000 mg produces mean hemoglobin increase of 8 g/L over 8 days 2
• Reticulocytosis occurs at 3-5 days after administration, indicating active erythropoiesis 2

Population-Specific Considerations

• Inflammatory conditions (IBD, cancer, heart failure): Hepcidin activation impairs oral iron absorption, making IV ferric carboxymaltose particularly effective at overcoming this barrier 2, 5
• Chronic kidney disease: Demonstrates the highest magnitude ferritin response, likely due to baseline severe depletion and impaired oral absorption 1, 3
• Cancer patients on ESAs: Show dramatic ferritin increases (>1,000 ng/mL) but require monitoring to avoid iron overload (hold if ferritin >1,000 ng/mL) 2