Sodium ferric gluconate complex in the treatment of iron deficiency for patients on dialysis

Safety, therapeutic effectiveness, and cost of parenteral iron therapy

Patients have to discontinue the use of oral iron therapy due to the development of side effects and lack of long-term adherence to medication for iron deficiency anemia. This study aimed to evaluate the therapeutic effectiveness, safety, and cost of intravenous iron sucrose therapy. The computerized database and medical records of 453 patients diagnosed with iron deficiency anemia who received intravenous iron sucrose therapy for iron deficiency anemia between 2004 and 2008 were reviewed. The improvement of hematologic parameters and cost of therapy were evaluated 4 weeks after therapy. 453 patients (443 females, 10 males; age: 44.2 +/- 12.3 years) received iron sucrose therapy. Mean hemoglobin, hematocrit, and mean corpuscular volume values were 8.2 +/- 1.4 g/dL, 26.9 +/- 3.8%, and 66.1 +/- 7.8 fL, respectively, before therapy and 11.5 +/- 1.0 g/dL, 35.8 +/- 2.5%, 76.5 +/- 6.1 fL, respectively, after therapy (P < 0.001). A mean ferritin level of 3.4 +/- 2.4 ng/mL before therapy increased to 65.9 +/- 40.6 ng/mL after therapy (P < 0.001). All patients responded to intravenous iron therapy (transferrin saturation values of the patients were >50%). The mean cost of therapy was 143.07 +/- 29.13 US dollars. The therapy was well tolerated. Although the cost of intravenous iron sucrose therapy may seem high, a lack of adherence to therapy and side effects including gastrointestinal irritation during oral iron therapy were not experienced during intravenous therapy.

Physicochemical properties of ferumoxytol, a new intravenous iron preparation

BACKGROUND

Intravenous iron is a critical component of anaemia management. However, currently available preparations have been associated with the release of free iron, a promoter of bacterial growth and oxidative stress.

MATERIALS AND METHODS

We determined the molecular weight, dialysability and capacity for free iron release of ferumoxytol, a semi-synthetic carbohydrate-coated superparamagnetic iron oxide nanoparticle. Ferumoxytol was compared with three intravenous iron preparations in clinical use: iron dextran (low molecular weight), sodium ferric gluconate and iron sucrose. Intravenous iron preparations were also incubated in rat, and pooled human sera (at concentrations of 600 microM and 42 microg mL(-1) respectively) from healthy subjects.

RESULTS

The molecular weight of ferumoxytol was 731 kDa. The relative order of molecular weight was as follows: ferumoxytol > iron dextran > iron sucrose > sodium ferric gluconate. The least ultrafilterable iron was observed with ferumoxytol and the most with ferric gluconate. The least dialysable free iron was observed with ferumoxytol and the most with ferric gluconate. Incubation of intravenous iron preparations in rat or pooled human sera demonstrated minimal free iron release with ferumoxytol. The order of catalytic iron release as detected by the bleomycin detectable iron assay was as follows: ferumoxytol < iron dextran < iron sucrose < ferric gluconate. A similar trend was observed for the in vivo serum concentration of free iron in rats.

CONCLUSIONS

In vitro observations from these experiments suggest that ferumoxytol has a favourable profile in terms of tendency to release free iron, in comparison with currently available intravenous iron preparations.

Drug Insight: safety of intravenous iron supplementation with sodium ferric gluconate complex

Intravenous iron is necessary for optimal management of anemia in patients receiving hemodialysis and is utilized in the majority of these patients in the US. The availability of nondextran formulations of intravenous iron has significantly improved the safety of its use. The nondextran iron formulation sodium ferric gluconate complex (SFGC) has been extensively studied in the hemodialysis population, with two large phase IV trials documenting its safety. SFGC is efficacious and, at recommended doses, is associated with a low incidence of adverse events. There have been few comparative studies of the nondextran intravenous iron preparations; however, they are known to have different pharmacokinetic characteristics. There is also evidence to indicate that these compounds differ in terms of their cytotoxic and proinflammatory properties, and their propensity to induce oxidative stress. This paper reviews the current literature on the safety of SFGC and examines the emerging safety issues surrounding the use of intravenous iron.

Treatment of iron deficiency anemia in pediatric inflammatory bowel disease

Anemia is a frequent extraintestinal manifestation of inflammatory bowel disease (IBD) that is commonly overlooked, despite its significant impact on quality of life. Characteristic symptoms include chronic fatigue, headache, and subtle impairment of cognitive function, although some less common symptoms include dyspnea, dizziness, pica, angular stomatitis, shortened attention span, and esophageal webs. Several types of anemia are associated with IBD, but iron deficiency anemia (IDA) accounts for the majority of cases and others include anemia of chronic disease, anemia associated with vitamin deficiency (vitamin B12 and folate), autoimmune anemia, and anemia caused by medication used to treat IBD. The diagnosis of IDA relies on laboratory blood tests. Therefore, these tests should be obtained on a regular basis because characteristic symptoms may be absent or not readily recognized by patients and their clinicians. Complete blood count may suffice; however, iron studies and serum vitamin levels may be necessary to differentiate between specific types of anemia. During the diagnostic process, it is important to consider coexistence of different types of anemia, especially if no response to therapy is noted. The therapy for anemia is directed towards treatment of the underlying inflammatory process and supplemental therapy, depending on the type of deficiency. Iron deficiency anemia is treated with iron preparations, first orally, and if unresponsive or if associated with untoward adverse events leading to decrease in adherence with the therapeutic regimen, with intravenous preparations. Intramuscular therapy has been abandoned due to high rate of complications. Intravenous therapy may be administered as a multiple-dose regimen (intravenous iron sucrose and gluconate) or as a single intravenous dose (iron dextran), which is associated with a higher risk of allergic infusion reactions and requires obligatory test dose administration. Treatment with erythropoietin is reserved for a select subgroup of patients with anemia of chronic disease. With appropriate treatment, the majority of patients with IBD will have significant improvement or resolution of anemia, which can lead to a better quality of life. However, a high index of suspicion should be maintained in order to identify the precise cause of anemia and to prescribe the appropriate therapy.

Sodium ferric gluconate complex therapy in anemic children on hemodialysis

Pediatric patients with end-stage renal disease undergoing hemodialysis (HD) frequently develop anemia. Administration of recombinant human erythropoietin (rHuEPO) is effective in managing this anemia, although the additional demand for iron often results in iron deficiency. In adult patients undergoing HD, intravenous (IV) iron administration is known to replenish iron stores more effectively than oral iron administration. Nevertheless, IV iron supplementation is underutilized in pediatric patients, possibly because of unproved safety in this population. This international, multicenter study investigated the safety and efficacy of two dosing regimens (1.5 mg kg(-1) and 3.0 mg kg(-1)) of sodium ferric gluconate complex (SFGC) therapy, during eight consecutive HD sessions, in iron-deficient pediatric HD patients receiving concomitant rHuEPO therapy. Safety was evaluated in 66 patients and efficacy was evaluated in 56 patients. Significant increases from baseline were observed in both treatment groups 2 and 4 weeks after cessation of SFGC dosing for mean hemoglobin, hematocrit, transferrin saturation, serum ferritin, and reticulocyte hemoglobin content. Efficacy and safety profiles were comparable for 1.5 mg kg(-1) and 3.0 mg kg(-1) SFGC with no unexpected adverse events with either dose. Administration of SFGC was safe and efficacious in the pediatric HD population. Given the equivalent efficacy of the two doses, an initial dosing regimen of 1.5 mg kg(-1) is recommended for pediatric HD patients.

Intravenous iron in a primary-care clinic

The preferable route of iron delivery for most iron-deficient patients is oral. Parenteral iron therapy is used in patients who cannot tolerate oral iron or in cases in which oral iron is not sufficiently effective. The most frequent indications for parenteral iron therapy are unbearable gastrointestinal side effects induced by oral iron itself, worsening of inflammatory bowel disease symptoms, insufficient intestinal absorption, renal failure-caused anemia that is treated with erythropoietin, and unresolved ongoing bleeding, which would cause the acceptable oral doses of iron therapy to be exceeded. The serious adverse effects of iron dextran that was used in the past could explain the reluctance of medical personnel to prescribe this effective treatment. Patients with iron deficiency anemia were treated with intravenous iron in a primary care clinic. The iron gluconate was given in a dosage of 62.5 mg diluted in 150 mL of normal saline and was infused intravenously over 30 min, while iron sucrose was given in a dosage of 100 mg diluted in the same volume of normal saline and given at the same rate. In total, 724 infusions were administered to 57 patients. Iron sucrose was used in 628 infusions, and iron gluconate was used in the remaining 96. The frequency of the infusion treatments depended on the underlying disease and ranged from three times a week to once a month. Adverse effects were seldom observed and were minor in patients receiving iron gluconate, and were not registered at all in patients treated with iron sucrose. Two cases of flushing with paresthesias occurred. Slowing the infusion rate successfully eliminated these side effects. One case of hypotension was treated successfully with 500 cc of normal saline infusion. One case of dropout occurred, due to the patient's refusal to cooperate. No anaphylactic reactions were observed. Iron gluconate and iron sucrose are effective and safe for use in primary care clinics. The risk of adverse effects is low.

Labile iron in parenteral iron formulations: a quantitative and comparative study

BACKGROUND

Evidence of iron-mediated oxidative stress, neutrophil dysfunction and enhanced bacterial growth after intravenous (IV) iron administration has been ascribed to a labile or bioactive iron fraction present in all IV iron agents.

METHODS

To quantify and compare the size of the labile fraction in several classes of IV iron agents, we examined iron donation to transferrin (Tf) in vitro. We added dilutions of ferric gluconate, iron sucrose and each of two iron dextran preparations to serum in vitro, passed the resulting samples through alumina columns to remove iron agent and free organic iron, and measured Tf-bound iron in the resulting eluates. Comparing results to serum samples without added iron, we calculated delta Tf-bound iron for each agent at each concentration. Finally, we compared delta Tf-bound iron to the concentration of added agent and calculated the percent iron donation to Tf.

RESULTS

We found that Tf-bound iron increased with added iron concentration for each agent: delta Tf-bound iron was directly related to the concentration and type of iron agent (P<0.001). Mean percent iron donation to Tf ranged from 2.5 to 5.8% with the following progression: iron dextran-Dexferrum<iron dextran-INFeD<iron sucrose<ferric gluconate. Pairwise differences between agents for percent iron donation were statistically significant (P<0.05) only between ferric gluconate and both iron dextran agents, and between iron sucrose and iron dextran-Dexferrum.

CONCLUSIONS

Approximately 2-6% of total iron in commonly used IV iron compounds is available for in vitro iron donation to Tf. This fraction may contribute to evidence of bioactive iron in patients after IV iron administration.

Controversies in iron management

BACKGROUND

Iron therapy is required in hemodialysis patients receiving erythropoietic stimulators in order to achieve the target hemoglobin in the most efficient way. While oral iron has been disappointing in this regard, parenteral iron has been widely used, despite a significant incidence of severe side effects when iron dextran is used. The recent availability of a more effective form of oral iron (heme-iron), and safer forms of parenteral iron (iron sucrose and iron gluconate) has made iron management in this population simpler. Many questions remain, however, about the use, efficacy, and safety of these compounds in hemodialysis patients.

METHODS

Current literature was reviewed and combined with the authors' clinical experience to address a number of current questions regarding the use of iron in hemodialysis patients.

RESULTS

Although oral non-heme iron is infrequently sufficient to maintain iron stores in hemodialysis patients, recent studies suggest that heme-iron may be more useful in this regard. Heme-iron is absorbed to a greater extent than non-heme iron, and is better tolerated. Small studies have shown that when heme-iron is administered, less parenteral iron and lower doses of erythropoietin (EPO) are needed to maintain target hemoglobin. Current evidence suggests that both iron sucrose and iron gluconate are safer than iron dextran, and the latter should only be used in extraordinary circumstances. While in vitro studies have demonstrated some differences in the effects of iron sucrose and iron gluconate on cellular toxicity, the clinical importance of these has not been determined. Both compounds can be used safely for repletion and maintenance therapy, and doses of up to 300 mg of either are generally well tolerated when such higher doses are needed, as in peritoneal dialysis (PD) patients or chronic kidney disease (CKD) patients not on dialysis.

CONCLUSION

A number of questions remain regarding the appropriate use, efficacy, and potential toxicity of iron therapy in dialysis patients. Further prospective research should address the myriad questions raised in this review.

Impairment of Transendothelial Leukocyte Migration by Iron Complexes

ABSTRACT. Although iron sucrose and iron gluconate are generally well tolerated in patients who are treated for renal anemia, recent clinical studies and cell culture experiments suggested significant toxicity and long-term side effects arising from the use of these iron complexes. Because of the possible role of iron in infection or cardiovascular disease, it was theorized that parenteral iron compounds influence endothelial and PMN interactionin vitro. A well-established double-chamber method was used to assess the effect of different concentrations of iron sucrose and iron gluconate (1, 25, 50, and 100 μg/ml) on the transendothelial migration of PMN. Preincubation of PMN and endothelial cells as well as preincubation of PMN alone with 25, 50, or 100 μg/ml iron resulted in a significant decrease in PMN migration. In contrast, after incubation of the endothelial cells alone with iron, no reduction in the transendothelial migration of PMN was observed. Preincubation of PMN and/or endothelial cells with 1 μg/ml iron did not lead to any decrease in the rate of migrated PMN. The only significant change in experiments with 1 μg/ml was an increase in PMN migration after preincubation of endothelial cells and PMN with iron gluconate. A four-way ANOVA showed a significant effect of the iron concentration (P< 0.000001), of type of iron complex (P< 0.005), of the preincubation of endothelial cell (P< 0.001), and of the preincubation of PMN with iron (P< 0.000001) on PMN diapedesis. It is concluded that iron sucrose and iron gluconate cause a significant inhibition of transendothelial migration of PMN. E-mail: Guerkan.Sengoelge@univie.ac.at

The management of anemia in pediatric peritoneal dialysis patients. Guidelines by an ad hoc European committee

Anemia is common in chronic renal failure. Guidelines for the diagnosis and treatment of anemia in adult patients are available. With respect to the diagnosis and treatment in children on peritoneal dialysis, the European Pediatric Peritoneal Dialysis Working Group (EPPWG) has produced guidelines. After a thorough diagnostic work-up, treatment should aim for a target hemoglobin concentration of at least 11 g/l. This can be accomplished by the administration of erythropoietin and iron preparations. Although there is sufficient evidence to advocate the intraperitoneal administration of erythropoietin, most pediatric nephrologists still apply erythropoietin by the subcutaneous route. Iron should preferably be prescribed as an oral preparation. Sufficient attention has to be paid to the nutritional intake in these children. There is no place for carnitine supplementation in the treatment of anemia in pediatric peritoneal dialysis patients.

Chronic use of sodium ferric gluconate complex in hemodialysis patients: safety of higher-dose (> or =250 mg) administration

BACKGROUND

Almost all hemodialysis (HD) patients require intravenous iron therapy to correct their anemia and maintain their iron stores. Sodium ferric gluconate complex (SFGC) is approved by the Food and Drug Administration (FDA) for treatment of iron deficiency anemia in HD patients at individual doses up to 125 mg over 10 minutes (12.5 mg/min) and has been shown to have a superior safety profile compared with iron-dextran. Higher individual doses of SFGC would permit more rapid repletion of iron stores and greater flexibility in maintenance iron therapy as well as simplify treatment of peritoneal dialysis patients and chronic kidney disease patients.

METHODS

The authors reviewed the safety and tolerability of higher-dose SFGC infusions (> or =250 mg) in 144 HD patients who were previously tolerant to a single 125-mg dose of SFGC. These 144 patients received a total of 590 doses of > or =250 mg of SFGC; 571 doses were 250 mg SFGC, and most of these were infused over 1 hour, an infusion rate of 4.17 mg/min. The other 19 doses were 312.5 mg (n = 1), 375 mg (n = 14), and 500 mg (n = 4). Infusion rates varied from 1.22 mg/min to 25.0 mg/min.

RESULTS

Only one patient was considered intolerant to higher-dosing SFGC after having pruritus after a second 250-mg dose of SFGC. Three patients had nonserious events that did not preclude further dosing of SFGC.

CONCLUSION

Administration of 250 mg SFGC over 1 hour is safe and well tolerated. Individual doses of 375 mg and 500 mg SFGC also were well tolerated, but further research and experience are needed to confirm the safety and tolerance of these doses.

Sodium ferric gluconate complex in hemodialysis patients. II. Adverse reactions in iron dextran-sensitive and dextran-tolerant patients

BACKGROUND

Iron dextran administration is associated with a high incidence of adverse reactions including anaphylaxis and death. Although dextran, rather than iron, is believed to be the cause of these reactions, it is not known whether iron dextran-sensitive patients can be safely administered another form of parenteral iron, sodium ferric gluconate in sucrose (SFGC).

METHODS

In a 69 center, prospective, double-blind, controlled trial of safety and tolerability of SFGC, the rate of reactions to SFGC and placebo in 144 iron dextran-sensitive patients was compared with 2194 patients who were previously tolerant to iron dextran preparations. Serum tryptase levels, a marker of mast cell degranulation, also were measured.

RESULTS

Among 143 iron dextran-sensitive patients exposed to SFGC, three (2.1%) were intolerant. All three had suspected allergic events to SFGC, including one patient with a serious reaction (0.7%). One dextran-sensitive patient (0.7%) had a suspected allergic reaction after placebo. In contrast, among 2194 iron dextran-tolerant patients, reactions to SFGC were significantly less common, with SFGC intolerance seen in seven patients (0.3%; P = 0.020), including five (0.2%) who had suspected allergic events (P = 0.010), but none who had serious events (0.0%; P = 0.061). Two iron dextran-tolerant patients (0.09%) had allergic-like reactions following placebo injections. Two of the three suspected allergic events in the iron dextran-sensitive group were confirmed as mast cell dependent by a 100% increase in serum tryptase, while there were no confirmed allergic events in the iron dextran-tolerant group. Long-term exposure to SFGC in iron dextran-sensitive patients resulted in intolerance in only one additional patient and no serious adverse events.

CONCLUSIONS

Patients with a history of iron dextran sensitivity had approximately sevenfold higher rates of reaction to both placebo and SFGC compared to iron dextran tolerant patients. However, logistic regression analysis, performed to account for the higher reaction rate to placebo, suggests that this increased reactivity was not drug-specific nor immunologically mediated, but represented host idiosyncrasy. These results support the conclusions that reactions to SFGC can be attributed to pseudoallergy, and that SFGC is not a true allergen.

Iron sucrose: the oldest iron therapy becomes new

Several parenteral iron preparations are now available. This article focuses on iron sucrose, a hematinic, used more widely than any other for more than five decades, chiefly in Europe and now available in North America. Iron sucrose has an average molecular weight of 34 to 60 kd, and after intravenous (IV) administration, it distributes into a volume equal to that of plasma, with a terminal half-life of 5 to 6 hours. Transferrin and ferritin levels can be measured reliably 48 hours after IV administration of this agent. Iron sucrose carries no "black-box" warning, and a test dose is not required before it is administered. Doses of 100 mg can be administered over several minutes, and larger doses up to 300 mg can be administered within 60 minutes. The efficacy of iron sucrose has been shown in patients with chronic kidney disease (CKD) both before and after the initiation of dialysis therapy. Iron sucrose, like iron gluconate, has been associated with a markedly lower incidence of life-threatening anaphylactoid reactions and may be administered safely to those with previously documented intolerance to iron dextran or iron gluconate. Nonanaphylactoid reactions, including non-life-threatening hypotension, nausea, and exanthema, also are extremely uncommon with iron sucrose. Management of patients with the anemia of CKD mandates that we carefully examine the effectiveness and safety of this oldest of iron preparations and the accumulating present-day data regarding it and contemporaneous agents.