Efficacy of oral iron therapy in patients receiving recombinant human erythropoietin

Single-dose pharmacokinetics of sodium ferric gluconate complex in iron-deficient subjects

STUDY OBJECTIVES

To determine the single-dose pharmacokinetics of intravenous sodium ferric gluconate complex in sucrose injection (SFGC) in iron-deficient human volunteers, and to assess iron transport.

DESIGN

Open-label, randomized study.

SETTING

Clinical research facility.

SUBJECTS

Fourteen iron-deficient men and women.

INTERVENTIONS

Subjects were randomized to receive a single intravenous dose of either SFGC 62.5 mg administered over 30 minutes or SFGC 125 mg over 60 minutes. Five days later, the same subjects were rerandomized to receive a second intravenous dose of SFGC, either 62.5 mg administered over 4 minutes or 125 mg over 7 minutes.

MEASUREMENTS AND MAIN RESULTS

Blood samples were collected at predefined times before, during, and up to 72 hours after the infusion to determine the single-dose pharmacokinetics of SFGC. Assays were performed for both total iron and transferrin-bound iron, from which drug-bound iron could be calculated. Urine was collected over 24 hours before dosing and for 24 hours after the start of infusion to determine the renal elimination of iron. Clearance of SFGC from serum was rapid and far exceeded rates reported for iron dextran. Pharmacokinetic parameters were unaffected by dose or infusion rate. Serum iron derived from SFGC did not exceed the binding capacity of transferrin. Serum iron from SFGC became rapidly available (< 24 hrs) as transferrin-bound iron, but only after passage through another compartment, presumably the reticuloendothelial system (RES). At least 80% of the administered iron was transported to bone marrow within 24 hours after infusion.

CONCLUSIONS

Iron derived from SFGC appears to be rapidly transferred to a bioavailable iron compartment as transferrin-bound iron after digestion in the RES. At the doses administered in this study, liberation of potentially toxic, free iron was not detectable.

Iron therapy in the pediatric hemodialysis population

Iron therapy maintains iron stores and optimizes the response to recombinant human erythropoietin (r-HuEPO) in patients with end-stage renal failure. Information is limited, however, regarding the preferential route of iron administration in pediatric patients receiving hemodialysis. Therefore, we prospectively randomized 35 iron-replete patients (aged >1 to <20 years) to receive up to 16 weeks of maintenance i.v. ( n=17) or daily oral ( n=18) iron. Eligible patients had received hemodialysis for >2 months, had a baseline transferrin saturation [TSAT] >20%, and were receiving maintenance r-HuEPO. Treatment arms were evenly distributed with respect to baseline demographic and clinical characteristics, with no statistically significant differences in baseline hemoglobin (Hb), hematocrit (Hct), reticulocyte Hb content (CHr), serum ferritin (SF), TSAT, or r-HuEPO dose. In the 35 patients, i.v. iron dextran and not oral iron was associated with a significant increase (138.5 to 259.1 ng/ml, P=0.003) in SF. A comparison of the change in SF between the i.v. iron group and the oral iron group was also significant ( P=0.001). Whereas only i.v. iron was associated with a significant decrease in the dose of r-HuEPO (234.0 to 157.6 U/kg per week, P=0.046) and an increase of the CHr (29.2 to 30.1 pg, P=0.049), these changes were not significantly different from those experienced by patients in the oral iron group. In both groups, the Hct remained stable and in neither group was there a significant change in the TSAT. In summary, although both oral and i.v. iron maintained patients in an iron-replete state in this short-term study, only i.v. therapy allowed for a significant improvement in iron stores.

On the relative safety of parenteral iron formulations

BACKGROUND

Intravenous iron is usually required to optimize the correction of anaemia in persons with advanced chronic kidney disease and end-stage renal disease. Randomized clinical trials may have insufficient power to detect differences in the safety profiles of specific formulations.

METHODS

We obtained data from the US Food and Drug Administration on reported adverse drug events (ADEs) related to the provision of three formulations of intravenous iron during 1998-2000. We estimated the relative risks [odds ratios (OR)] of ADEs associated with the use of higher molecular weight iron dextran and sodium ferric gluconate complex compared with lower molecular weight iron dextran using 2 x 2 tables.

RESULTS

The total number of reported parenteral iron-related ADEs was 1981 among approximately 21,060,000 doses administered, yielding a rate of 9.4 x 10(-5), or approximately 94 per million. Total major ADEs were significantly increased among recipients of higher molecular weight iron dextran (OR 5.5, 95% CI 4.9-6.0) and sodium ferric gluconate complex (OR 6.2, 95% CI 5.4-7.2) compared with recipients of lower molecular weight iron dextran. We observed significantly higher rates of life-threatening ADEs, including death, anaphylactoid reaction, cardiac arrest and respiratory depression among users of higher molecular weight compared with lower molecular weight iron dextran. There was insufficient power to detect differences in life-threatening ADEs when comparing lower molecular weight iron dextran with sodium ferric gluconate complex.

CONCLUSIONS

Parenteral iron-related ADEs are rare. Using observational data, overall and most specific ADE rates were significantly higher among recipients of higher molecular weight iron dextran and sodium ferric gluconate complex than among recipients of lower molecular weight iron dextran. These data may help to guide clinical practice, as head-to-head clinical trials comparing different formulations of intravenous iron have not been conducted.

Anemia in the critically ill

The anemia of critical illness is a distinct clinical entity with characteristics similar to that of chronic disease anemia. Several solutions to the processes of anemia, such as blunted erythropoietin production and erythropoietin response and abnormalities in iron metabolism have been developed. The transfusion of RBCs provides immediate correction of low hemoglobin levels, which may be of value in patients with life-threatening anemia. Avoidance of RBC and blood component transfusion, however, is becoming increasingly important as data of adverse clinical outcomes in critically ill patients become clearer. Although the optimal hemoglobin in critically ill patients is not determined, this organ system has a generous reserve. Short-term compensated anemia is tolerated well, while exogenous erythropoietin allows patients to achieve higher hemoglobin concentrations without exposure to transfused blood/blood components. A recent randomized trial enrolled over 1300 critically ill patients to receive either 40,000 units of exogenous erythropoietin or placebo. These authors found that patients randomized to erythropoietin received significantly less allogeneic RBC transfusions and had significantly greater increases in hemoglobin. Although no differences were found between groups in gross clinical outcomes (ie, death, renal failure, myocardial infarction), this study did not have the power to identify small differences in outcomes. This and other studies of exogenous erythropoietin therapy in critically ill patients clearly demonstrate that the bone marrow in many of these patients will respond to the administration of erythropoietin despite their illness, suggesting a blunted production of erythropoietin rather than a blunted response to erythropoietin. Exogenous erythropoietin therefore represents a therapeutic option for treating anemia in critical illness. Acute events in medicine and surgery often lead to many patients becoming anemic. Solutions to this process of anemia should be focused on preventing such events. Anemia after surgery represents an area for prevention. Blood conservation strategies can be performed with adequate results. Monk et al randomized 79 patients undergoing radical prostatectomy to preoperative autologous donation (PAD), preoperative exogenous erythropoietin therapy plus ANH immediately following induction of general anesthesia, and ANH alone. This study concluded that all three techniques resulted in similar hemostasis outcomes (eg, bleeding and transfusion rates), but ANH alone was the least expensive, and ANH plus exogenous erythropoietin and ANH alone resulted in a higher ICU hematocrit compared with PAD. Regardless of these prophylactic strategies, patients still become anemic after surgery or during critical illness. This acute event anemia usually is treated with RBC transfusion; however, autologous blood recovery (cell salvage systems) has been shown to be effective in patients with acute bleeding-related anemia, and this may reduce patients' exposure to allogeneic blood in these patients. There are no universally accepted treatment guidelines for managing anemia, and practice differs between clinicians, hospitals, regions, and countries. Transfusion medicine is evolving and incorporating many new pharmacological agents into the armamentarium of anemia and bleeding therapy. Accumulating evidence suggests that anemia in critically ill patients is common and correlated with poor outcomes. The management of anemia can improve outcomes; however, the optimal management of anemia is not performed universally. New approaches, continued research, and an understanding of anemia may result in more consistent and improved outcomes for critically ill patients.

Sodium ferric gluconate complex in haemodialysis patients: a prospective evaluation of long-term safety

BACKGROUND

A previous single dose placebo-controlled double-blinded trial showed an extremely low (0.4%) intolerance rate of sodium ferric gluconate complex (SFGC) in SFGC-naive haemodialysis patients. No large prospective trials have assessed the safety of SFGC during repeated exposure in the outpatient haemodialysis setting.

METHODS

Chronic haemodialysis patients completing the single-dose trial of SFGC were eligible to participate in this prospective, multicentre, open-label, long-term evaluation of SFGC, designed to record adverse events occurring up to 72 h post-dose. Patients received as many as 20 ampules (1250 mg total) of SFGC at an investigator-determined dose and rate over a 9 month evaluation period.

RESULTS

Among 1412 enrolled patients at 54 centres, 1321 received 13,151 infusions of SFGC. Most doses (94.8%) were < or =125 mg and the majority were given over 10 min. Infusion rates ranged from <5 to 125 mg/min. There were no life-threatening events. Fifty-one patients (3.9%) experienced an adverse event, possibly related to SFGC. Of these, one experienced a serious event (hypotension). Five patients (0.4%) experienced an event that precluded SFGC readministration: pruritus (three), vasodilatation (one) and loss of taste (one). Among 372 patients (28.2%) receiving angiotensin-converting enzyme inhibitor (ACEI) therapy, adverse events were neither more common nor more severe than in the other patients.

CONCLUSIONS

Repeated doses of SFGC are very well tolerated in haemodialysis patients. No life-threatening events were observed in over 13,000 doses administered. Administration of SFGC to patients using ACEI is safe and does not increase the incidence or severity of adverse events to SFGC.

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.

Incidence of side-effects associated with high-dose ferric gluconate in patients with severe chronic renal failure

Ferric gluconate complex in sucrose (Ferrlecit) has been associated with less side-effects than iron dextran; however, the recommended dose of 62.5-125 mg per treatment is only suitable for haemodialysis (HD) patients. We retrospectively analysed the incidence of the side-effects associated with a high dose of Ferrlecit infusion (20 treatments in 13 patients; 10 treatments of 250 mg/3-4 h, and 10 treatments of 500 mg/5 h infusion). The patients were in the age range of 32-75 years old, seven with chronic renal failure (CRF), and six on dialysis treatment. One (10%) of the 10 treatments using a 250 mg dose was complicated with severe nausea/vomiting, diarrhoea and a burning sensation in the feet. Three (30%) of the 10 treatments using a 500 mg dose were complicated with: chills, severe nausea/vomiting, hypotension and syncope in one; severe nausea/vomiting, diarrhoea and hypotension in one; and an episode of vomiting in one patient. A single treatment with a 250 mg dose resulted in no significant change in haematological parameters. A single treatment with a 500 mg dose resulted in a significant increase in haemoglobin (Hgb) and haematocrit (Hct), but only a rising trend in serum iron,% transferrin saturation and ferritin pre versus 1-2 months postinfusion. In conclusion, Ferrlecit doses of 250 or 500 mg are complicated with significant untoward reactions in 10-30% of patients, in a dose-dependent fashion.

Oral use of iron with vitamin C in hemodialyzed patients

OBJECTIVE

To investigate if oral use of Sorbifer Durules (EGIS Pharmaceutical Ltd, Budapest, Hungary) (1 tablet/d) is adequate for the maintenance of serum iron and vitamin C in normal range during recombinant human erythropoietin treatment in hemodialyzed patients. One tablet of Sorbifer Durules contains 100 mg of Fe(2+) and 60 mg of vitamin C.

DESIGN

Short-term, open-label clinical trial.

SETTING

Hemodialysis units.

PATIENTS

Twenty-four adult patients with end-stage renal disease on hemodialysis.

INTERVENTION

Four-week treatment period of Sorbifer Durules, preceded and followed by iron and vitamin C washout periods.

MAIN OUTCOME MEASURE

Fasting predialysis serum samples were collected on days 0, 28, 56, and 84 to determine hematocrit, blood hemoglobin, serum iron, total iron-binding capacity, transferrin saturation, ferritin, vitamin C, and plasma oxalate.

RESULTS

Four-week treatment in hemodialyzed patients by Sorbifer Durules led to significant increase of hematocrit, blood hemoglobin, serum iron and vitamin C. This treatment did not influence the level of plasma oxalate.

CONCLUSION

Oral dose of one tablet of Sorbifer Durules per day is adequate for the maintenance of serum iron in normal range during recombinant human erythropoietin treatment in hemodialyzed patients. This treatment simultaneously prevented the development of serum vitamin C deficiency and did not lead to further increase of plasma oxalate in these patients.

Lack of reaction to ferric gluconate in hemodialysis patients with a history of severe reaction to iron dextran

Iron deficiency is the most common cause of a poor response to recombinant human erythropoietin (rHuEPO) in patients receiving long-term dialysis, who are known to absorb oral iron preparations poorly. This retrospective case series reports our preliminary observation of five patients receiving long-term dialysis in a tertiary care university hospital who had responded poorly to rHuEPO because of iron deficiency. These patients also had a history of severe, potentially life-threatening reaction to intravenous iron dextran preparation, but they tolerated the newly available ferric gluconate complex in sucrose with no untoward effects. These results suggest that the parenteral administration of ferric gluconate can be safe for those who require iron therapy and who have had a severe reaction to iron dextran.

Sodium ferric gluconate complex in hemodialysis patients: adverse reactions compared to placebo and iron dextran

BACKGROUND

Parenteral iron is often required by hemodialysis patients to maintain adequate iron stores. Until recently, the only available form of intravenous iron was iron dextran, which is associated with significant adverse reactions, including anaphylaxis and death. Sodium ferric gluconate complex (SFGC) was recently approved for use in the U.S. under FDA's priority drug review. This Phase IV study was designed to evaluate the safety of a single dose of intravenous SFGC as compared to placebo and a historical iron dextran control.

METHODS

This multicenter, crossover, randomized, double blind, placebo-controlled prospective comparative study was performed in hemodialysis patients requiring at least 125 mg of elemental iron. The historical control was obtained from a meta-analysis of four publications examining outcomes in patients exposed to iron dextran. SFGC naïve patients were administered SFGC without a test dose, undiluted, at a rate of 125 mg over 10 minutes, and compared to placebo comprising bacteriostatic saline.

RESULTS

A total of 2534 patients were enrolled. The incidence of drug intolerance (an adverse event precluding re-exposure) was significantly less [0.44%, confidence interval (CI) 0.21 to 0.71%] after SFGC as compared to the iron dextran control (2.47%, CI 1.87 to 3.07%, P < 0.0001), but higher than after placebo (0.1%, P = 0.02). There was no difference found between SFGC and placebo in serious adverse events. A single life-threatening event occurred after SFGC (0.04%, CI 0.00 to 0.22%), which was significantly less than following iron dextran (0.61%, CI 0.36 to 0.86%), P = 0.0001.

CONCLUSION

SFGC is well tolerated when given by intravenous push without a test dose. SFGC has a significantly lower incidence of drug intolerance and life-threatening events as compared to previous studies using iron dextran. The routine use of iron dextran in hemodialysis patients should be discontinued.

Total dose infusion iron dextran therapy in predialysis chronic renal failure patients

BACKGROUND

Intravenous iron therapy is now the standard modality of iron supplementation in hemodialysis patients, but its role in predialysis chronic renal failure patients is less well established. The efficacy and safety of intravenous iron dextran as a total dose infusion in predialysis chronic renal failure patients, not receiving erythropoietin was assessed in this study.

METHODS

Fifty-six predialysis chronic renal failure patients with anemia, not receiving erythropoietin were included in the study, after obtaining informed consent. Hemoglobin, serum creatinine, creatinine clearance rate and serum ferritin were assessed in all the patients at baseline. Iron dextran in a dose of 1 g dissolved in 500 mL normal saline was administered to all patients as a total dose infusion over 6 h after a prior test dose. Patients were kept in hospital under observation for at least 24 h. All the parameters were repeated in all the patients at 12 weeks and in 21 patients at 1 year.

RESULTS

The mean hemoglobin (g/dL) in the patients at baseline and at 12 weeks was 8.28 +/- 0.57 and 9.22 +/- 0.44 respectively (p < 0.001). The mean serum ferritin (ng/mL) increased from 29.73 +/- 9.38 at baseline to 218.43 +/- 15.66 at 12 weeks (p < 0.00001). The mean ferritin value in the 21 patients at 1 year was 136.5 +/- 23.4 (p < 0.01). There were no major adverse events and only minor side effects were observed in 4.9% patients.

CONCLUSION

Iron dextran as a total dose infusion corrects anemia in predialysis patients and is an effective method to replenish iron stores. The effect on serum ferritin are evident even at 1 year after the total dose infusion.

Considerations for optimal iron use for anemia due to chronic kidney disease

BACKGROUND

Availability of recombinant human erythropoietin (rHuEPO) has improved the treatment of anemia due to chronic kidney disease (CKD). Iron deficiency is the most common cause of resistance to rHuEPO therapy, contributing to ineffective erythropoiesis and hematocrit/hemoglobin values below the recommended target range (33%-36%/11-12 g/dL). I.v. iron supplementation is necessary to meet increased iron demands from stimulation of erythropoiesis and chronic blood loss; however, questions remain as to the optimal supplementation strategy to maintain appropriate yet safe iron status. Treatment guidelines for anemia management have been developed through the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI).

OBJECTIVE

This review presents the basis of need for the NKF-K/DOQI guidelines and includes detailed information concerning iron physiology, metabolism, iron preparations, and evaluation of iron status.

METHODS

This review was based on a MEDLINE search and complemented by references from the NKF-K/DOQI guidelines (whose review extended beyond MEDLINE). References focusing on normal iron physiology and metabolism, alterations in iron physiology in patients with CKD, laboratory evaluation methods, and strategies for iron supplementation were obtained from MEDLINE and reviewed for content.

RESULTS

Controversy over appropriate use of iron supplementation has led to disparity in accepted practice procedures. Oral iron (ferrous salts and polysaccharide iron complex) and i.v. iron preparations (iron dextran, sodium ferric gluconate, and iron sucrose) are available. Problems with oral iron supplementation include limited absorption and patient noncompliance. Although most available data on i.v. iron use in the United States are specific to iron dextran preparations, published information based on clinical use of sodium ferric gluconate and iron sucrose products has been promising. The use of chronic i.v. iron administration to sustain iron stores has been more widely accepted to prevent development of absolute and functional iron deficiency.

CONCLUSIONS

Although iron therapy is commonly warranted in patients with CKD, questions remain as to the most favorable supplementation strategy to optimize therapy through improvements in hematocrits, efficient use of rHuEPO, and maintenance of appropriate and safe iron levels. Clinicians will need to devise strategies based on the compilation of information from clinical experience and the available literature. Clinical practice guidelines devised by the NKF-K/DOQI have provided a useful tool for the medical community using both these resources.

Diagnostic value of iron indices in hemodialysis patients receiving epoetin

BACKGROUND

Iron deficiency remains a common cause of hyporesponsiveness to epoetin in hemodialysis patients. However, considerable controversy exists regarding the best strategies for diagnosis and treatment.

METHODS

As part of a multicenter randomized clinical trial of intravenous versus subcutaneous administration of epoetin, we made monthly determinations of serum iron, total iron binding capacity, percentage transferrin saturation, and serum ferritin. If a patient had serum ferritin <100 ng/mL or the combination of serum ferritin <400 ng/mL and a transferrin saturation <20%, he/she received parenteral iron, given as iron dextran 100 mg at ten consecutive dialysis sessions. We analyzed parenteral iron use during the trial, the effect of its administration on iron indices and epoetin dose, and the ability of the iron indices to predict a reduction in epoetin dose in response to parenteral iron administration.

RESULTS

Eighty-seven percent of the 208 patients required parenteral iron to maintain adequate iron stores at an average dose of 1516 mg over 41.7 weeks, or 36 mg/week. Only two of 180 patients experienced serious reactions to intravenous iron administration. Two thirds of the patients receiving parenteral iron had a decrease in their epoetin requirement of at least 30 U/kg/week compared with 29% of patients who did not receive iron (P = 0.004). The average dose decrease 12 weeks after initiating iron therapy was 1763 U/week. A serum ferritin <200 ng/mL had the best positive predictive value (76%) for predicting a response to parenteral iron administration, but it still had limited clinical utility.

CONCLUSIONS

Iron deficiency commonly develops during epoetin therapy, and parenteral iron administration may result in a clinically significant reduction in epoetin dose. The use of transferrin saturation or serum ferritin as an indicator for parenteral iron administration has limited utility.

A randomized, controlled parallel-group trial on efficacy and safety of iron sucrose (Venofer) vs iron gluconate (Ferrlecit) in haemodialysis patients treated with rHuEpo

BACKGROUND

The objectives of the present trial were to compare the efficacy and safety of two i.v. iron preparations with respect to haemoglobin levels, iron status and recombinant human erythropoetin (rHuEpo) dosage requirements in stable, rHuEpo-treated haemodialysis patients (maintenance phase of iron treatment) over 6 months.

METHODS

A total of 59 patients were randomized and assigned to one of two treatment groups and 55 patients were analysed (iron sucrose n=27; iron gluconate n=28). Iron sucrose was administered in a dose of 250 mg iron diluted in 100 ml normal saline given over 60 min once per month, while 62.5 mg iron as iron gluconate was given once per week in a slow push injection (5 min).

RESULTS

--Efficacy parameters: Haemoglobin levels could be maintained from baseline to endpoint in both groups. There were, however, more patients in the iron sucrose group than in the iron gluconate group for whom treatment was discontinued because their haemoglobin values exceeded 12.5 g/dl or ferritin values exceeded 1000 ng/ml (five vs two and three vs one patient, respectively). Transferrin saturation and serum ferritin increased significantly in both groups (+255.7 ng/ml with iron sucrose and +278.5 ng/ml with iron gluconate), while rHuEpo dosage did not change significantly throughout the study. --Safety parameters: There were a total of 174 infusions of iron sucrose and 720 injections of iron gluconate during the trial; all of them were well tolerated. In particular, we did not observe anaphylactoid reactions or any events suggestive of iron toxicity such as hypotension, dizziness, or nausea.

CONCLUSIONS

High doses of iron sucrose (Venofer((R)) at a dose of 250 mg/month) was equally effective in maintaining haemoglobin and equally well tolerated as low doses of iron gluconate (Ferrlecit((R)) at a dose of 62.5 mg once per week) in stable, rHuEpo treated haemodialysis patients.

Suspected iron dextran-related adverse drug events in hemodialysis patients

Despite the use of recombinant erythropoietin, anemia remains a significant problem for patients with end-stage renal disease, in part related to chronic dialysis-related blood loss and resultant iron deficiency. Because oral iron preparations have been relatively ineffective and poorly tolerated in this population, intravenous (IV) iron dextran has been widely prescribed, despite a finite risk for adverse effects associated with its use. We analyzed data from Fresenius Medical Care North America (FMCNA) clinical variance reports to determine the incidence of suspected iron dextran-related adverse drug events (ADEs) and associated patient characteristics, dialysis practice patterns, and outcomes. We used a case-cohort study design, comparing individuals who experienced suspected ADEs with the overall FMCNA population. Among 841,252 IV iron dextran administrations from October 1998 through March 1999, there were 165 reported suspected ADEs, corresponding to an overall rate of 0.000196%, or approximately 20 per 100,000 doses. Forty-three patients (26%) required an independent emergency department evaluation, 18 patients (11%) required hospitalization, and 1 patient (0.6%) died. Dyspnea (43%), hypotension (23%), and neurological symptoms (23%) were the most common major ADEs; nausea (34%), vomiting (23%), flushing (27%), and pruritus (25%) were the most common other ADEs. ADEs were 8.1-fold more common among patients administered Dexferrum (American Regent Laboratories, Inc, Shirley, NY) compared with those administered InFed (Watson Pharmaceuticals, Phoenix, AZ). In summary, serious adverse reactions to IV iron dextran are rare in clinical practice. The risk appears to depend on the specific formulation of IV iron dextran. Otherwise, iron dextran-related ADEs are difficult to predict.

Unanticipated favorable effects of correcting iron deficiency in chronic hemodialysis patients

BACKGROUND

Correction of anemia in hemodialysis patients is seldom completely attained, and the response of parameters other than hemoglobin concentration to anemia correction has not been evaluated in detail.

METHODS

Laboratory parameters that suggest iron deficiency occurred in 10-15% of 206 recombinant human erythropoietin (rhEPO)-treated patients. Oral iron was given for 9 months and intravenous iron thereafter on a patient-specific basis when iron deficiency was evident. Eighty-seven hemodialysis patients with data for 12 months were followed for another 12 months. A computerized information system enabled data management and analysis.

RESULTS

With oral iron, serum ferritin decreased (P < 0.001), indicating further iron depletion. With intravenous iron, hemoglobin increased, evidence of iron deficiency decreased, and less rhEPO was needed. Striking macrocytosis appeared. Serum albumin and serum creatinine/kg body weight (an index of muscle mass) increased, while blood pressure decreased. Data were reanalyzed in four mean corpuscular volume (MCV) quartiles and two ferritin subsets at study onset. Iron deficient erythropoiesis (low MCV, mean corpuscular hemoglobin [MCH], and transferrin saturation) was striking in quartile 1; low ferritin was prevalent in all quartiles. With intravenous iron, hemoglobin increased only in quartile 1, the quartile with the greatest decrease (52%) in rhEPO dose. MCV increased in all quartiles (P < 0.001). Serum albumin increased in all MCV quartiles and both ferritin subsets, but significant creatinine/kg increase and blood pressure decrease occurred only in the low-ferritin subset.

CONCLUSIONS

Macrocytosis occurred with intravenous iron replacement. The universal MCV increase suggests unrecognized, inadequately treated, folic acid deficiency unmasked by an adequate iron supply. There was also improved well being. Effects were most clearly evident in patients with deficient iron stores.

Intravenous iron dextran treatment in predialysis patients with chronic renal failure

Iron deficiency anemia is common in patients with chronic renal failure not undergoing hemodialysis. Current therapy consists of oral or intravenous (IV) iron dextran (IVID). The standard IV regimen is 100 to 200 mg/dose for a 1-g total dose. We hypothesized that 500 mg/wk of IVID for two doses would be less costly and equally effective as 200 mg/wk for five doses. We prospectively studied 22 patients with creatinine clearances less than 50 mL/min who were not undergoing dialysis and had anemia and evidence of iron deficiency (ferritin level <100 ng/mL or transferrin saturation [TSAT] <20%). Patients were randomized into two groups: group I (n = 8), 200 mg/wk of IVID for 5 weeks, and group II (n = 14), 500 mg/wk of IVID for 2 weeks. All patients tolerated IVID infusions without serious adverse reactions. Over the 6-month follow-up, both groups experienced an increase in hemoglobin levels from baseline. Ferritin levels in both groups increased (P < 0.005), peaked at 2 weeks, then declined thereafter. Over the 6-month follow-up, both groups experienced significant improvement, although the beneficial effects of group II declined at a significantly faster rate than group I (P = 0.003). There was no significant difference in change in ferritin levels between groups. TSAT peaked at 2 weeks in both groups (P < 0. 001). Group I experienced a significant increase in TSAT throughout the 6-month follow-up (P < 0.03), and group II achieved a significant increase in TSAT at 2 weeks, but not at 3 and 6 months. There was no significant difference in pretreatment to posttreatment change in TSAT. Treatment in group II was 35.2% more cost-effective than in group I ($965 versus $1,490, respectively). We conclude that IVID, 500 mg/wk, for 2 weeks is as effective and safe as 200 mg/wk for 5 weeks, but much less costly.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Effects of erythropoietin therapy on iron absorption in chronic renal failure

The effect of erythropoietin administration on the absorption of dietary and therapeutic iron was examined in patients with anemia of chronic renal failure on maintenance hemodialysis. Absorption from test meals tagged extrinsically with iron 55, iron 59, or both was determined 2 weeks later by using incorporated red blood cell radioactivity and whole body counting. In an initial study of food iron absorption, the effect of initiating erythropoietin therapy was determined by measuring the absorption of heme and nonheme iron before and 2 weeks after the administration of 64 U/kg body weight erythropoietin (range, 46-85 U/kg body weight) three times weekly. Absorption of heme iron increased 1.6-fold from 18.6% to 30.1% (P < .05), and nonheme iron increased 3.7-fold from 1.3% to 4.9% (P < .01) after erythropoietin therapy. In a second study therapeutic iron absorption was evaluated at baseline and after erythropoietin administration (63 U/kg body weight (range, 48-74 U/kg body weight) three times weekly). The absorption of 50 mg of iron as ferrous sulfate increased 2.4-fold from 3.8% to 9.4% (P < .05) when given without food and 4.2-fold from 1.4% to 5.9% (P < .05) when given with food after erythropoietin administration. After adjusting for changes in iron stores with serum ferritin after erythropoietin therapy, the enhanced erythropoiesis associated with erythropoietin therapy increased absorption about 2-fold, which was similar to the response observed previously in normal subjects. In a final study we examined the absorption of therapeutic iron during the steadystate phase of erythropoietin therapy after an erythroid response to erythropoietin had occurred. The absorption of 50 mg of iron was lower than that occurring with the initiation of erythropoietin therapy at 2.2% when given alone and 1.3% when taken with food. We conclude that iron absorption with or without erythropoietin stimulation is unimpaired in patients with chronic renal failure.

Anemia management of adult hemodialysis patients in the US results: from the 1997 ESRD Core Indicators Project

BACKGROUND

The Health Care Financing Administration's End-Stage Renal Disease (ESRD) Core Indicators Project collects clinical information on prevalent adult patients receiving in-center hemodialysis (HD) care in the United States to assess the quality of care delivered. Although hematocrit values, transferrin saturations, and iron prescription practices have improved over the last five years, we sought to determine whether continued opportunities for improvement of this domain of care exist.

METHODS

A random sample of 7292 adult in-center HD patients was selected. Dialysis facility staff provided clinical information for the period of October through December 1996 for 6858 (94%) patients; complete laboratory information was available from 4991 (73%) returned forms. Hematocrit values, transferrin saturations, serum ferritin concentrations, epoetin alfa dosing, and iron prescriptions were abstracted from patient medical records to assess anemia management practices.

RESULTS

The mean hematocrit for this cohort was 32.6 +/- 3.5%. Seventy-two percent of patients had hematocrit values> 30%. Forty-two percent had hematocrit values of 33 to 36%, and 10% were severely anemic (hematocrit <28%). Ninety-four percent of the patients received epoetin alfa intravenously (i.v.) and 6% subcutaneously. The mean weekly dose was 202.4 +/- 137.2 units/kg. The mean transferrin saturation was 27.4 +/- 12.6%; 73% of patients had a mean transferrin saturation > or = 20%. The mean serum ferritin concentration was 386 +/- 422 ng/mL; 79 and 12% of patients had a serum ferritin concentration of> 100 and> 800 ng/mL, respectively. Nine percent of the sample (N = 434) had a transferrin saturation <20% and serum ferritin concentration <100 ng/mL. Regardless of the patient's transferrin saturation, approximately three fourths of the patients received either oral or i.v. iron, and only approximately one half of the patients received i.v. iron. Of the subset of patients with transferrin saturation <20% and serum ferritin concentration <800 ng/mL, only 53% were prescribed intravenous iron. Multivariate linear regression analysis revealed that serum albumin, urea reduction ratio, age, and transferrin saturation were significantly positively associated with hematocrit. Epoetin alfa dose and serum ferritin concentration were significantly and negatively associated with the hematocrit (P < 0.001).

CONCLUSION

Although substantial improvements have been made in anemia management for adult in-center HD patients over the past five years, significant opportunities persist to improve iron prescription practices.

[Evaluating the impact of a hematinic iron-rich nutritional supplement]

A quasi-experimental epidemiological study was performed to evaluate the effect of a nutritional supplement made from bovine blood on human blood parameters. Healthy women who were neither pregnant nor breast-feeding were allocated to two groups: study (n=32) and control (n=17). Women in the study group received 0.5 mg of iron per day, while controls received placebo. Food intake frequency and side effects related to ferrous sulfate were recorded. A 24-hour dietary recall was performed every two weeks, and blood samples were collected to determine biochemical parameters. Compared to controls, the study group showed higher serum iron and iron retention capacity, lower calorie, protein, and vitamin C intake, and lower consumption of dairy products and fruit. Adjusted mean blood parameters were calculated using ANOVA. The output showed increased serum iron (p=0.009) and decreased iron retention capacity (p=0.031) at the end of the study. The results favor use of the product to treat iron deficiency anemia.

An indistinct balance: the safety and efficacy of parenteral iron therapy

Recombinant epoetin therapy and correction of the chronic anemia of renal failure have greatly reduced the number of red cell transfusions and hence the propensity to iron overload. The majority of HD patients require intravenous iron therapy to achieve the hematocrit levels that correspond to improved outcome measures. Although the short-term benefits of intravenous iron have been clearly defined, the long-term risks of intravenous iron are less well-defined. Iron overload before the availability of epoetin constituted a serious problem; our review of the literature does not decisively conclude that these patients had more serious bacterial infections or increased mortality when compared with their non-iron overloaded counterparts, unless chronic transfusion-related hepatic disease was superimposed. Specifically, no data unequivocally confirm that iron overload from parenteral iron contributes to all-cause patient morbidity or mortality. Furthermore, therapy that maintains intravenous iron optimal iron stores and replaces iron losses associated with the dialytic procedure does not engender iron overload in the carefully monitored patient. Optimized anemia therapy in ESRD requires individualized and specific application of epoetin and iron for each patient, and significant cost savings can result from such a strategy. Prospective studies are clearly necessary to define those parameters that reflect adequacy of iron storage in renal failure patients. We should develop alternative means of iron delivery and develop monitors that accurately discriminate between patients who will respond to additional iron therapy and those who will not. Whether ferritin should be supplanted by another parameter and whether iron itself poses an increased risk to those patients it has so beneficially served are issues that must be resolved. Until these answers are known, the importance of carefully crafted iron therapy cannot be overstated.

Beneficial effects of iron therapy in renal failure patients on hemodialysis

Iron deficiency is a common problem in patients treated with hemodialysis. If not detected and treated appropriately, the effectiveness of recombinant human erythropoietin therapy is compromised. Much has been learned in recent years with respect to iron therapy for hemodialysis patients. A series of studies have clearly defined the efficacy of intravenous iron compounds, and recently released clinical practice guidelines have set the appropriate clinical context for the use of these agents. The purpose of this article is to examine the beneficial effects of iron replacement therapy for hemodialysis patients.

Strategies for iron supplementation: oral versus intravenous

Iron supplementation has become an integral part of the management of patients receiving epoetin therapy, and clinicians have found it necessary to learn how and when to use it to the best advantage. Three routes of administration for iron are available: oral, intramuscular, and intravenous. Oral iron has the advantage of being simple and cheap, but it is limited by side-effects, poor compliance, poor absorption, and low efficacy. Intravenous iron is the best means of guaranteeing delivery of readily available iron to the bone marrow, but it requires greater clinical supervision. The i.v. iron preparations vary widely in their degradation kinetics, bioavailability, side-effect profiles, and maximum dose for single administration. Iron dextran is hampered by a small but significant risk of anaphylaxis, whereas all i.v. iron preparations can induce "free iron" reactions if the circulating plasma transferrin is overloaded. Intravenous iron may be given in advance of epoetin therapy, as concomitant treatment to prevent the development of iron deficiency, as treatment of absolute or functional iron deficiency, or as adjuvant therapy to enhance the response to epoetin in iron-replete patients. Markers of iron status that may indicate a need for i.v. iron include a serum ferritin of less than 100 microg/liter, a transferrin saturation of less than 20%, and a percentage of hypochromic red cells more than 10%. Various regimens are available for giving i.v. iron: low-dose administration of 20 to 60 mg every dialysis session in hemodialysis patients, medium-dose administration of 100 to 400 mg, and high-dose administration of 500 to 1000 mg. Iron sodium gluconate can only be given as a low-dose regimen because of toxicity, whereas the only preparation suitable for high-dose administration is iron dextran. Although concerns have been raised regarding iron overload and long-term toxicity with i.v. iron therapy in terms of increased risk of infections, cardiovascular disease, and malignancy, there is little evidence to substantiate this in patients receiving epoetin. Care should be taken, however, to prevent the serum ferritin rising above 800 to 1000 microg/liter and the transferrin saturation above 50%. Provided this is done, the benefits of i.v. iron almost certainly outweigh the risks in terms of optimizing the response to epoetin therapy.

Sodium ferric gluconate complex in sucrose is safe and effective in hemodialysis patients: North American Clinical Trial

A new intravenous (i.v.) iron compound, sodium ferric gluconate complex in sucrose (Ferrlecit, R&D Laboratories, Inc, Marina Del Rey, CA), was administered over 8 consecutive dialysis days in equally divided doses to a total of either 0.5 or 1.0 g in a controlled, open, multicenter, randomized clinical study of anemic, iron-deficient hemodialysis patients receiving recombinant human erythropoietin (rHuEPO). Effectiveness was assessed by increase in hemoglobin and hematocrit and changes of iron parameters. Results were compared with historically matched controls on oral iron. High-dose i.v. treatment with 1.0 g sodium ferric gluconate complex in sucrose resulted in significantly greater improvement in hemoglobin, hematocrit, iron saturation, and serum ferritin at all time points, as compared with low-dose i.v. (0.5 g) or oral iron treatment. Despite an initial improvement in mean serum ferritin and transferrin saturation, 500 mg i.v. therapy did not result in a significant improvement in hemoglobin at any time. Eighty-three of 88 patients completed treatment with sodium ferric gluconate complex in sucrose: 44 in the high-dose and 39 in the low-dose group. Two patients discontinued for personal reasons. The other three discontinued because of a rash, nausea and rash, and chest pain with pruritus, respectively. In comparison with 25 matched control patients, adverse events could not be linked to drug therapy, nor was there a dose effect. In conclusion, sodium ferric gluconate complex in sucrose is safe and effective in the management of iron-deficiency anemia in severely iron-deficient and anemic hemodialysis patients receiving rHuEPO. This study confirms the concepts regarding iron therapy expressed in the National Kidney Foundation Dialysis Outcomes Quality Initiative (NKF-DOQI) that hemodialysis patients with serum ferritin below 100 ng/mL or transferrin saturations below 18% need supplementation with parenteral iron in excess of 1.0 g to achieve optimal response in hemoglobin and hematocrit levels.

Secular trends in recombinant erythropoietin therapy among the U.S. hemodialysis population: 1990-1996

BACKGROUND

Chronic anemia is a major cause of morbidity among the end-stage renal disease (ESRD) population. Recombinant erythropoietin (rHuEPO) has been recognized as a major advance in the treatment of anemia among the ESRD population. This study examines the secular trends in the use of and response to rHuEPO therapy among severely, moderately and mildly anemic hemodialysis patients.

METHODS

We designed a cohort analytic study using seven years of claims data. The study population comprised all facility-based adult hemodialysis patients receiving rHuEPO therapy, who were initially reimbursed by Medicare in each of the first quarter of the calendar years 1990 through 1996 (N = 64,957).

RESULTS

Between 1990 and 1996, the mean rHuEPO dose increased by 139% for the patient cohorts with a first observed hematocrit < 0.25, 122% for the 0.25 to 0.29 cohorts, and 107% for the > or = 0.30 cohorts, and produced a 0.02 to 0.03 increase in achieved hematocrit (A-Hct) over this time. Dosing of rHuEPO did not appear to be influenced by patient or provider characteristics, although African-Americans, the elderly, non-diabetics and persons receiving dialysis in a non-profit facility had a larger percent change in hematocrit compared to their counterparts (P < 0.001).

CONCLUSIONS

The results of the clinical use of rHuEPO seven years after FDA approval found in the general ESRD hemodialysis population have not equaled the results obtained in the initial clinical trials. Overall, our findings suggest that substantial increases in rHuEPO dose provided to anemic patients have resulted in only modest increases in hematocrit in the seven years since rHuEPO's introduction. Resistance to rHuEPO, prior rHuEPO treatment, inadequate use of supplemental iron, and policy and financial incentives may explain this finding.

Drugs acting on blood and/or blood forming organs

Pharmacologic therapy for anemia is oriented toward (1) providing components needed for red blood cell production (vitamin B12 and folic acid), including hemoglobin synthesis (iron and other minerals), and (2) stimulating bone marrow formation of red blood cells. Drugs used to stimulate bone marrow activity will be the focus of this article.

Achieving target hematocrit in dialysis patients: new concepts in iron management

The management of anemia in dialysis patients involves a comprehensive understanding of the role of erythropoietin deficiency and of the importance of adequate available iron. It is clear that iron and recombinant human erythropoietin (rHuEPO) in concert allow the clinician to achieve a given target hematocrit in dialysis patients. By first repleting and then maintaining iron stores, and with an appreciation of the concept of functional iron deficiency, the nephrologist can achieve target hematocrits with the lowest necessary dose of rHuEPO. Iron repletion and maintenance is difficult to achieve with oral iron, and parenteral iron is needed in most cases. New protocols for ongoing parenteral maintenance therapy with iron dextran or iron gluconate, a form of iron likely to be available soon in the United States, should lead to achievement of target hematocrits in a greater number of patients and be cost-effective in improving patient outcomes.

Markers of masked iron deficiency and effectiveness of EPO therapy in chronic renal failure

Recombinant erythropoietin (rHuEPO) is well established in the management of anemia of chronic renal disease. However, a number of clinical issues, including the best laboratory indicators of an imminent marrow response to rHuEPO replacement, the ideal measurements to detect masked iron deficiency, and optimal methods of iron replacement, remain unanswered. To investigate these issues, studies were performed in anemic chronic hemodialysis patients. A number of standard hematologic measurements in addition to automated reticulocyte counts (Sysmex R-1000) and serum transferrin receptors (TfR) were obtained in these patients. A response to initiation of rHuEPO administration could be predicted if the serum TfR concentration was less than 6 mg/L (normal, 3.8 to 8.5 mg/L). In patients on rHuEPO, an imminent hemoglobin response to an increased rHuEPO dose could be predicted after 1 week based on a greater than 20% increase from baseline in the serum TfR or absolute reticulocyte count, with a sensitivity of 92%. In patients on rHuEPO replacement with serum ferritin levels greater than 30 microg/L, none of the panel of tests, including serum TfR, reliably detected masked iron deficiency. In a long-term study over 5 months in patients on a stable maintenance dose of EPO, a gradual decline in total body iron occurred, even in subjects with initial adequate iron stores, and despite taking 50 mg elemental iron daily as oral ferrous sulphate. The serum TfR is useful for predicting a hemoglobin response when initiating rHuEPO therapy, and combined with automated reticulocyte counting it is valuable for predicting a hemoglobin response when increasing the dose of rHuEPO. The serum TfR loses its specificity for detecting tissue iron deficiency in patients on maintenance rHuEPO therapy because of increased erythropoiesis, which itself raises serum TfR levels.

Iron management in end-stage renal disease

One of the important components of successful anemia therapy in patients with end-stage renal disease (ESRD) treated with recombinant human erythropoietin is the maintenance of adequate available iron. To accomplish this task, iron status must be serially monitored and supplemental iron administered as required. Among nonuremic subjects, the body's iron supply is tightly conserved, and iron deficiency usually develops only when chronic blood loss occurs. In patients with ESRD, iron deficiency occurs more frequently, because of increased external losses of iron, decreased availability of the body's storage of iron, and perhaps a deficit in intestinal iron absorption. Detecting iron deficiency in these patients can be difficult because of the inaccuracy of available diagnostic tests. The goals of iron therapy in ESRD include the prevention of iron deficiency by chronically supplementing iron, and the prompt treatment of overt iron deficiency. Oral iron supplements are inexpensive and safe, but poor patient compliance and reduced intestinal absorption may limit their effectiveness. Intravenous iron supplements have a greater efficacy then oral iron, which must be weighed against the small risk of allergic reactions. We present strategies for using the various diagnostic tests and treatment modalities to effectively manage iron supply for predialysis, hemodialysis, and peritoneal dialysis patients.

Iron utilization after iron dextran administration for iron deficiency in patients with dialysis-associated anemia: a prospective analysis and comparison of two agents

We sought to determine the rate and extent of iron utilization after administration of intravenous iron dextran and to compare the efficacy of iron dextran preparations of differing molecular weight. We randomized patients to receive either a 500-mg dose of iron dextran molecular weight (MW) 267,000 (group A) or iron dextran MW 96,000 (group B) administered in five sequential 100-mg doses, and examined indices of iron status before and at weekly intervals up to 4 weeks later. Although mean iron utilization was greater in the nine group A patients (46.7% +/- 21.3%) than in the 11 group B patients (31.7% +/- 26.6%), the difference was not statistically significant (P = 0.19). Iron utilization in both groups was substantially incomplete. Changes in serum ferritin and hemoglobin did not differ between the treatments (P = 0.49 and P = 0.34, respectively). We conclude that iron utilization after iron dextran administration is substantial within the first week after completing a course of therapy, associated with stable iron indices after the first 2 weeks, and incomplete for at least the first 4 weeks. Degree of iron utilization appears independent of molecular weight within the range we examined.