Comparison of Ferumoxytol to Oral Iron in Hemodialysis Patients

Comparison of Ferumoxytol to Oral Iron in Hemodialysis Patients
NAAC Review Published: March 4, 2009

Iron deficiency is a frequent cause of anemia, which is nearly universal in stage 5D of patients with chronic kidney disease (CKD) on hemodialysis (HD). This deficiency can be caused by blood loss, poor iron absorption, or increased erythropoiesis after receiving erythropoiesis-stimulating agents (ESAs). Intravenous iron replacement therapy is commonly recommended in HD patients because oral iron is poorly tolerated and absorbed, and has lengthy administration periods. The physiochemical properties of IV iron are designed to maximize the release of iron within the cells of the reticuloendothelial system and limit side effects. In particular, clinical studies have shown that ferumoxytol – a novel iron oxide nanoparticle designed to minimize immunological sensitivity – is well tolerated and can be administered quickly. Thus, a recent Phase III trial examined the efficacy and safety of ferumoxytol compared to oral iron in HD patients.

The randomized, controlled, open-label study examined 230 HD patients with CKD stage 5D who received either two injections of ferumoxytol (510 mg) within 7 days or daily doses of oral iron (200 mg) over a period of 21 days. The study was completed after 35 days, and the primary efficacy endpoint was the change in hemoglobin (Hb) from baseline to day 35. Change in transferrin saturation (TSAT) and reticulocyte hemoglobin content (CHr) were also observed as secondary endpoints. In addition, patients were given the option to receive an additional dose of ferumoxytol on day 35 for a nonrandomized readmission phase.

Compared with oral iron, ferumoxytol treatment led to improvements in all efficacy endpoints. At day 35, average Hb levels increased 1.02 ± 1.13 g/dL in the ferumoxytol group and 0.46 ± 1.06 g/dL in the oral iron group. Mean increases in TSAT and CHr levels were also significantly greater in the ferumoxytol group. Of the 46 patients who chose to enter the readmission phase, those who previously received ferumoxytol in the first 35 days achieved a greater increase in Hb than those who received oral iron (0.96 ± 0.69 g/dL and 0.78 ± 0.86 g/dL, respectively). Finally, adverse events were less frequent in the ferumoxytol group, while serious adverse events were similar in both study groups.

Because the prevalence of iron deficiency is extremely high in HD patients (especially those receiving ESAs), proper treatment is an essential component of anemia management. The authors concluded that the results of this study point to a strong effectiveness of ferumoxytol, as well as a convenient administration method that could enhance patient compliance and cost management. Furthermore, the physiochemical properties of ferumoxytol demonstrate low immunogenicity and stable binding to iron, factors that greatly improve its safety profile over oral iron therapies.

Provenzano R, Schiller B, Rao M, Coyne D, Brenner L, Pereira BJ. Ferumoxytol as an Intravenous Iron Replacement Therapy in Hemodialysis Patients. Clin J Am Soc Nephrol. 2009 Feb;4(2):386-93.

NAAC Expert Commentary:
Intravenous (IV) iron therapy is an important part of anemia management in patients with advanced chronic kidney disease (CKD) and has been shown repeatedly to be superior to oral iron in CKD patients for the purposes of increasing Hb levels and/or reducing ESA doses. Of currently available iron preparations – iron sucrose, iron gluconate in sucrose complex, and iron dextrans, only the iron dextrans can be administered in single “total dose infusions” of 1,000 mg or more. The other preparations are generally only given, for safety reasons, in doses of about 300 mg per dose, or less. Concern about severe anaphylactic reactions with iron dextrans has limited their use; hence, the increased interest in ferumoxytol.

The findings of this study, similar to results from a similar study by Spinowitz et al1 in non-dialysis CKD patients, are not unexpected – IV iron is more effective than oral iron. Of great interest to clinicians is the safety profile of ferumoxytol. Transient hypotension occurs rarely with ferumoxytol and adverse event rates were similar to those reported with the use of oral iron (placebo in the Singh study2). Both studies excluded patients with allergy to iron products or multiple other drugs and did not allow comparison with other IV irons. So while ferumoxytol appears to be highly effective, quite safe, and is likely to be a welcome addition to our IV iron pharmacopeia, direct head-to-head comparisons with other IV irons in less highly selected patients are needed.
References

1. Spinowitz BS, Kausz AT, Baptista J, Noble SD, Sothinathan R, Bernardo MV, Brenner L, Pereira BJ. Ferumoxytol for treating iron deficiency anemia in CKD. J Am Soc Nephrol. 2008 Aug;19(

:1599-1605. Link.
2. Singh A, Patel T, Hertel J, Bernardo M, Kausz A, Brenner L. Safety of ferumoxytol in patients with anemia and CKD. Am J Kidney Dis. 2008 Nov;52(5):907-15. Link.

Last Updated: March 4, 2009
View original published article at PubMed

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