One year's experience with recombinant erythropoietin in children undergoing continuous ambulatory or cycling peritoneal dialysis

Use of erythropoiesis-stimulating agents in children with chronic kidney disease: a systematic review

Background

Erythropoiesis-stimulating agents (ESAs) revolutionized the management of anaemia in chronic kidney disease (CKD) when introduced in the late 1980s. A range of ESA types, preparations and administration modalities now exist, with newer agents requiring less frequent administration. Although systematic reviews and meta-analyses have been published in adults, no systematic review has been conducted investigating ESAs in children.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for the conduct of systematic reviews was used. All available literature on outcomes relating to ESAs in children with CKD was sought. A search of the MEDLINE, CINAHL and Embase databases was conducted by two independent reviewers. Inclusion criteria were published trials in English, children with chronic and end-stage kidney disease and use of any ESA studied against any outcome measure. An assessment of risk of bias was carried out in all included randomized trials using the criteria from the Cochrane Handbook for Systematic Reviews of Interventions. Two tables were used for data extraction for randomized and observational studies. Study type, participants, inclusion criteria, case characteristics, follow-up duration, ESA type and dosage, interventions and outcomes were extracted by one author.

Results

Of 965 identified articles, 58 were included covering 54 cohorts. Six were randomized trials and 48 were observational studies. A total of 38 studies assessed the efficacy of recombinant human erythropoietin (rHuEPO), 11 of darbepoetin alpha (DA) and 3 of continuous erythropoietin receptor activator (CERA), with 6 studies appraising secondary outcome measures exclusively. Recruitment to studies was a consistent challenge. The most common adverse effect was hypertension, although confounding effects often limited direct correlation. Two large cohort studies demonstrated a greater hazard of death independently associated with high ESA dose. Secondary outcome measures included quality of life measures, growth and nutrition, exercise capacity, injection site pain, cardiovascular function, intelligent quotient, evoked potentials and platelet function.

Conclusions

All ESA preparations and modes of administration were efficacious, with evidence of harm at higher doses. Evidence supports individualizing treatments, with strong consideration given to alternate treatments in patients who appear resistant to ESA therapy. Further research should focus on randomized trials comparing the efficacy of different preparations, treatment options in apparently ESA-resistant cohorts and clarification of meaningful secondary outcomes to consolidate patient-relevant indices.

Effect of Erythropoietin in Continuous Ambulatory Peritoneal Dialysis Patients: Comparison between Intravenous and Intraperitoneal Administration

The administration of recombinant human erythropoietin (rHuEPO) in CAPD patients is usually done subcutaneously. Only a few authors have reported on its intraperitoneal (IP) administration. We compared the effect of IP administration of rHuEPO in CAPD patients to that of intravenous (IV) administration. Ten anemic CAPD patients injected rHuEPO into their dialysis bag once a day, 3 times a week, for 18 weeks. The initial dose was 12000 U. The dwell time of the exchanges with rHuEPO was about 6 hours. Nineotheranemic CAPD patients were treated with IV rHuEPO once a week for 18 weeks. The initial dose was 6000 U. In the IP group the hematocrit rose from 24.04±2.7% to 33.3±3.8% (mean±SD). In the IV group 2 patients were excluded from the efficiency evaluation. In 7 of the 9 patients in the IV group, the hematocrit rose from 23.27±2.6% to 32±5.5% (mean±SD).

The intraperitoneal administration of rHuEPO in CAPD patients is sufficient in improving anemia, although it requires a much larger dosage to yield the same level of improvement as the one obtained with the intravenous administration. However, in patients on continuous cycling peritoneal dialysis or IP dialysis, a smaller dosage during the prolonged dwell time may be effective.

Anti-erythropoietin antibodies followed by endogenous erythropoietin production in a dialysis patient

We present a case of a young girl with end-stage renal disease secondary to anti-glomerular basement membrane disease who was receiving maintenance peritoneal dialysis and developed pure red cell aplasia secondary to anti-erythropoietin (EPO) antibodies. This occurred 13 months after the initiation of EPO alfa therapy for anemia. Initially, the patient required intermittent red blood cell transfusions. After immunosuppressive therapy had been initiated with corticosteroids and cyclosporine, the EPO antibody levels decreased precipitously, associated with an increased level of endogenous EPO production. For the following 6 months, the patient maintained adequate (>10 g/dL) hemoglobin levels and did not require red cell transfusions.

Hemoglobin target in chronic kidney disease: a pediatric perspective

Erythropoietin has transformed the treatment of the anemia of chronic kidney disease (CKD) by preventing the need for blood transfusions and improving the quality of life in all patients, including children. Anemia in children, in the age group 1-19 years, may be defined as hemoglobin (Hgb) levels < 12.1-13.5 g/dl for boys and < 11.4-11.5 g/dl for girls, based on the National Health and Nutrition Examination Survey (NHANES) norms. The prevalence of anemia in children ranges from 31.2% in stage 1 CKD to 93.3% in stages 4 and 5 CKD. The recent publication of trials evaluating the optimal hemoglobin level in adult CKD patients has generated considerable uncertainty about the target Hgb level in children with CKD. It is unclear whether generalizing of results from these trials in adults to children is appropriate. Adequately powered, randomized, controlled studies have not been conducted on children, and none to our knowledge are currently planned. The Food and Drug Administration (FDA) offers scant guidance on the Hgb target level for children, other than implying that it should be no different from that for adults. The purpose of this editorial is to critically scrutinize whether there is a benefit to the normalization of anemia in children with CKD and whether adoption of the results from adult studies is appropriate.

Anemia in children with chronic kidney disease

Anemia is a common feature of chronic kidney disease, but the management of anemia in children is complex. Erythropoietin and supplemental iron are used to maintain hemoglobin levels. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) clinical practice guidelines for the management of anemia specifically in children were recently published. Pediatric nephrologists are encouraged to use current clinical practice guidelines and best evidence in conjunction with their clinical experience to optimally manage patients with anemia.

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.

The effects of recombinant human erythropoietin on growth and nutritional status

The availability of recombinant human erythropoietin (rhuEPO) has dramatically improved the care of children with chronic renal failure (CRF). Its use provides the opportunity to determine the relative contribution of anemia to the morbidity of CRF. Growth retardation, one of the most significant complications of CRF in children, is the consequence of several inter-related processes, including decreased protein and energy intake, metabolic bone disease, endocrine abnormalities, and anemia. The literature on the use of rhuEPO in children and data from a United States phase III double-blind, placebo-controlled study of rhuEPO in pediatric dialysis patients are reviewed to determine the effect of rhuEPO treatment on the nutritional status and growth of children with CRF. Despite subjective increases in appetite, there were no consistent improvements in dietary intake or anthropometric measures observed during rhuEPO treatment. Children gained weight during rhuEPO treatment; however, this was not generally associated with increased weight standard deviation scores. There was an improvement in growth velocity in some children; however, improvements in height standard deviation scores were infrequently seen. On review of the available literature, correction of anemia with rhuEPO has not been shown to improve the growth of children with CRF.

Recombinant human erythropoietin therapy in children on dialysis

The addition of recombinant human erythropoietin (rHuEPO) to the therapeutic regimen for children with chronic renal failure (CRF) is one of the most important improvements in care in the last 20 years. Anemia had played an important role in the morbidity of chronic dialysis treatment. Before the availability of rHuEPO, repeated erythrocyte transfusions provided incomplete treatment and had significant long-term sequelae. Recombinant erythropoietin treatment resulted in the amelioration of anemia and marked reduction in transfusions. Additional benefits of the correction of anemia with rHuEPO include improvements in exercise tolerance and regression of ventricular hypertrophy. Many rHuEPO-treated patients have had subjective increases in appetite, but there has been no consistent improvement in dietary intake or anthropometric measures. Correction of anemia with rHuEPO has not been shown to improve the growth of children with CRF receiving dialysis. The most significant adverse effects of rHuEPO are the development of iron deficiency and the exacerbation or development de novo of hypertension. RHuEPO treatment has been shown to treat the anemia of CRF in children safely and effectively. In most cases, putative inhibitors of erythropoiesis and blood loss can be overcome. Many of the symptoms previously ascribed to "uremia" have improved with correction of anemia. The full implications of treatment of anemia with rHuEPO will be clearer when the health outcomes for children who never become severely anemic or require transfusions are more completely studied.

Subcutaneous recombinant erythropoietin in preterminal renal insufficiency

Recombinant human erythropoietin was given to eight children and adolescents with stable chronic renal failure in the predialysis state. The hormone was administered subcutaneously, twice weekly for 12 weeks, at a starting dose of 50 U/kg per week. The dosage was adapted every 4th week. Target haemoglobin was 10.5-11.5 g/dl, and the target haematocrit 32%-35%. Baseline haemoglobin levels of 8.20 +/- 0.93 g/dl increased to 9.17 +/- 1.10, 10.38 +/- 1.18 and 11.19 +/- 0.84 g/dl (mean +/- SD) after 4, 8 and 12 weeks respectively. Serum ferritin levels decreased progressively despite iron supplementation. No side-effects were observed: creatinine clearances remained stable, blood pressure did not increase and none of the patients displayed either convulsions or thrombotic features. The study shows that subcutaneous recombinant human erythropoietin is both effective and safe in anaemic children and adolescents with chronic renal insufficiency.

Subcutaneous recombinant human erythropoietin in children with renal anemia on continuous ambulatory peritoneal dialysis

Subcutaneous recombinant human erythropoietin (rHuEpo) treatment of renal anemia was performed in four boys and eight girls on CAPD, aged 0.8-12.5 (mean 7.4) years. In contrast to previous studies, our therapeutic goal was not set with a hematocrit of 30% but with full correction of anemia. Following a maximum weekly rHuEpo dosage of median 120 (range 100-240) IU/kg body weight, hematocrit increased in 10 children from 24 (14-29)% within 12 (4-17) weeks to 40.1 (33.5-48.4)%. The weekly increase in hematocrit was 1.27 (0.5-3.1)%. The corrected reticulocyte count increased from 1.3 (0.7-1.8)% to 2.3 (1.4-3.9)% within 4 (2-6) weeks. Eight children fulfilled the protocol; six with an uncomplicated course were able to maintain a hematocrit of 37.1 (35.1-42.7)% with only one sc medication per week of approximately two-thirds of their highest weekly rHuEpo dosage. No serious adverse effect of rHuEpo therapy was observed.

Pharmacokinetics of recombinant human erythropoietin applied subcutaneously to children with chronic renal failure

The single-dose pharmacokinetics of recombinant human erythropoietin (rHuEPO) given SC was investigated in 20 patients aged 7-20 years at different stages of chronic renal failure. In a pilot study we confirmed the lower bioavailability of the drug in 2 children when given SC compared with the IV route (24% and 43%, respectively). Following administration of 4,000 units/m2, rHuEPO SC effective serum erythropoietin concentrations increased from a mean baseline level (+/- SD) of 23 +/- 13 units/l to a mean peak concentration of 265 +/- 123 units/l, which was reached after 14.3 +/- 9.4 h, followed by a slow decline until baseline values were attained at 72 h. Mean residence time was 30 +/- 9 h and mean elimination half-time 14.3 +/- 7 h. The single-dose kinetics of SC rHuEPO in children with different degrees of renal failure are comparable to those in adult patients. Possibly, the higher efficacy of SC rHuEPO in patients with renal anaemia compared with IV rHuEPO is related to its prolonged action.

Pharmacokinetics and hematologic response to subcutaneous administration of recombinant human erythropoietin in children undergoing long-term peritoneal dialysis: a multicenter study

For a study of the pharmacokinetics and hematologic response of subcutaneously administered recombinant human erythropoietin (rHuEPO), 24 children (mean age, 10 years 3 months; range, 3 months to 18 years) maintained by peritoneal dialysis and with anemia caused by end-stage renal failure (mean hemoglobin level, 6.5 gm/dl; range, 4.7 to 7.9) were treated with rHuEPO administered subcutaneously at an initial dose of 25 IU/kg twice per week. After a 4-week interval, in the case of no response (hemoglobin increase < or = 1 to 1.5 gm/dl per month) the rHuEPO dosage was increased every 4 weeks according to the following schedule: 50, 75, 100, and 150 IU/kg twice per week. The administration of rHuEPO produced a rapid increase in serum concentration with a mean peak level of 59.8 mU/ml after 9 hours. Mean area under the curve to 72 hours was 2020 mU/ml per hour (range, 568 to 6609); mean elimination half-life and mean residence time were, respectively, 25.2 hours (range, 6.2 to 58.7) and 42.0 hours (range, 10.9 to 96). Of 24 children entered in the study, six had the drug suspended early because of renal transplantation (n = 1), lack of compliance (n = 4), or severe worsening of hypertension (n = 1). Eighteen patients had increased hemoglobin levels (to 9.4 +/- 1.7 gm/dl after 24 weeks of treatment). No correlation was found between the increase in hemoglobin concentration and any of the pharmacokinetic data or the peak erythropoietin level reached during the kinetic profile. Eight children required an increase of antihypertensive medications to maintain satisfactory blood pressure values. We conclude that low doses of subcutaneously administered rHuEPO slowly release the drug into the blood and satisfactorily increase hemoglobin levels with very few side effects.

The effect of erythropoietin on the cellular defence mechanism of red blood cells in children with chronic renal failure

The glutathione redox system, haemoglobin (Hb) oxidation, the activity of antioxidant enzymes and the lipid peroxidation product malonyl dialdehyde (MDA) were studied in red blood cells (RBCs) during administration of recombinant human erythropoietin (rhEPO) over 12 weeks in ten children maintained on haemodialysis. A rapid increase in the reticulocyte count was accompanied by a slower rise in total Hb concentration. The mean level of oxidized glutathione (GSSG) increased from 13.2 +/- 5.3 nmol/g Hb to 56.7 +/- 15.8 nmol/g Hb 4 weeks after the start of rhEPO (P < 0.001), followed by a fall to the basal value. Reduced glutathione (GSH) levels showed a smaller though constant elevation during rhEPO therapy (P < 0.001). Before rhEPO treatment, incubation of RBCs for 1 h with acetylphenylhydrazine induced a decrease in GSH concentration compared with controls (P < 0.001), which became more pronounced in the first few weeks of rhEPO therapy (P < 0.001). In addition, the percentage of Hb derivatives (metHb and haemichrome) increased in the first 4 weeks of rhEPO therapy (P < 0.001). Although there was no significant difference between the values obtained preEPO and during EPO treatment, MDA levels were continuously higher and superoxide dismutase, catalase and glutathione peroxidase concentrations were lower than in the controls (P < 0.001). These results are compatible with oxidative damage to the RBCs in the early period of rhEPO therapy in children with end-stage renal failure. The GSH-GSSG system, as an important cellular defence mechanism of the RBCs, appears to be severely affected.

Intraperitoneal administration of recombinant human erythropoietin in children on continuous ambulatory peritoneal dialysis

In 16 children treated by continuous ambulatory peritoneal dialysis (CAPD) recombinant human erythropoietin was administered intraperitoneally for the treatment of renal anaemia. The mean treatment period was 8.3 months. Mean haemoglobin values increased from 4.9 mmol/l at start of therapy to 6.2 after 6 months. While 11 out of 16 children needed a total of 22 transfusions during the 6 months prior to therapy, no transfusions were needed after initiation of therapy. Patients started with a dose of 300 units/kg per week. After 6 months of therapy, the mean dose was 370 and after 12 months 279 units/kg per week. No major side-effects were observed. The incidence of peritonitis was not increased. We conclude that intraperitoneal administration of erythropoietin is effective in the treatment of renal anaemia in children treated by CAPD.

Human erythropoietin in children undergoing continuous ambulatory peritoneal dialysis

The effect of intravenous recombinant human erythropoietin (rHuEPO) by two different dosage regimes was evaluated in 12 anemic children on continuous ambulatory peritoneal dialysis (CAPD). Eight patients (group A) were treated once a week at a mean dose of 89 U/kg for 24 weeks. The other four patients (group B) were treated three times a week at a mean dose of 260 U/kg for 8 weeks, and then once a week at a mean dose of 88 U/kg for the next 16 weeks. In group A, the hematocrit (Ht) increased gradually and significantly from 19.9 +/- 2.1% to 28.7 +/- 1.5% at the 24th week, while in group B, it rapidly increased from 17.9 +/- 2.5% to 30.2 +/- 4.3% at the 8th week, and thereafter was maintained at a level of approximately 30%. However, there was no significant difference in the Ht between the two groups. In two of the four patients in group B, blood pressure increased from 136/87 mmHg to 168/102 mmHg and from 106/70 mmHg to 132/92 mmHg, at the 4th and the 8th weeks respectively, related to a rapid rise of the Ht. Neither antibody to rHuEPO nor other sides effect were evident. Gradual improvement of anemia by once-a-week intravenous administration of rHuEPO is advantageous for the quality of life in children on CAPD.

Recombinant human erythropoietin therapy in pediatric patients receiving long-term peritoneal dialysis

We evaluated the impact of (s.c.) recombinant human erythropoietin (r-HuEPO) therapy on the hematological status, exercise capacity, and dietary intake of nine pediatric patients (mean age 12.4 +/- 3.2 years) receiving long-term peritoneal dialysis. Five children without medical illness served as controls for the exercise testing portion of the study. Following 7.9 +/- 2.8 weeks of twice weekly r-HuEPO (50 units/kg per dose), the hematocrit increased from 21.9 +/- 3.5% to 31.3 +/- 2.5% (P less than 0.001). A further increase to 33.2 +/- 3.0% occurred after 2 months of once weekly therapy. The blood transfusion requirement decreased from 0.5 transfusions per patient-month to 0.05 transfusions per patient-month (P less than 0.01). Graded exercise testing demonstrated an increase in peak oxygen consumption from 17.8 +/- 5.2 to 24.0 +/- 7.6 ml/kg per min (P less than 0.01). The oxygen consumption at anaerobic threshold increased from 13.1 +/- 3.9 to 17.1 +/- 3.5 ml/kg per min (P less than 0.02). Treadmill time increased from 5.3 +/- 1.2 to 7.5 +/- 1.3 min (P less than 0.001). In each case, the percentage improvement was significantly greater than the improvement seen in the control population. Dietary evaluation revealed no significant change in caloric or protein intake, despite a subjectively improved appetite. r-HuEPO, given by the s.c. route, corrects the anemia and improves the exercise capacity of pediatric patients receiving long-term peritoneal dialysis.

Efficacy of once weekly erythropoietin therapy in children on continuous ambulatory peritoneal dialysis

The efficacy of recombinant human erythropoietin (rHuEPO) on 10 anemic children undergoing continuous ambulatory peritoneal dialysis (CAPD) was evaluated. A mean dose of 93 U/kg of rHuEPO was given once a week for 24 weeks, either intravenously to 5 children or subcutaneously to the other 5. Anemia improved in all children by this therapy. The mean hemoglobin and hematocrit levels increased gradually but significantly from 6.9 g/dl and 20.2% to 9.4 g/dl and 30.1%, respectively, at the end of the study. Elevation of blood pressure or other side effects were not noted in any patient. The present study indicates that the once-a-week injection of rHuEPO by the intravenous or subcutaneous route is effective in children undergoing CAPD.

Epoetin alfa in anaemic children or adolescents on regular dialysis

Eighteen patients aged 5-18 years on regular dialysis had a packed cell volume (PCV) less than 0.27. On treatment with epoetin alfa (EA) PCV increased by 0.05 or more in all patients. Iron supplementation was necessary in 13 patients with a ferritinaemia less than 300 micrograms/l before study. During treatment, plasma potassium increased significantly and more vigorous antihypertensive measures were required in 8 patients, 5 of them being already on antihypertensive drugs before EA. Iliofemoral thrombosis occurred in 1 patient 10 days after renal transplant. The data indicate that EA ameliorates the anaemia of chronic renal disease. The main concerns arising during treatment with EA are hyperkalaemia, arterial hypertension and possibly thrombosis.