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

Cardiopulmonary fitness in children/adolescents with chronic kidney disease and the impact of exercise training: a systematic review and meta-analysis of observational study and randomized controlled trials

BACKGROUND

This systematic review and meta-analysis aimed to evaluate differences in cardiopulmonary fitness between healthy controls and children/adolescents with chronic kidney disease (CKD) and the effects of exercise training.

METHODS

PubMed, Embase, Scopus and Web of Science were searched for published studies from reception to 14 June 2023, and updated search on 15 October 2023. The included observational studies reported on cardiorespiratory fitness, included maximal oxygen uptake (VO2max), peak oxygen consumption (VO2peak) and 6-minute walk distance (6MWD), in children/adolescents with CKD and age-matched healthy controls, as well as clinical intervention trials of exercise training on cardiorespiratory fitness in samples of children and/or adolescents up to 19.

RESULTS

Fifteen observational studies and five clinical trials were included, respectively. The studies found that the mean cardiopulmonary fitness was 1.82 standardized mean differences (SMDs) units (95% confidence interval (95% CI) 1.43-2.20) lower in children/adolescents with CKD than in healthy controls or reference values. Except for pre-dialysis CKD patients, peritoneal dialysis, haemodialysis and kidney transplant recipients had significantly lower cardiorespiratory fitness than healthy controls. The results of a meta-analysis based on a pre-post single-arm trial showed that compared to baseline, exercise training improved the 6MWD by approximately 58.17 m (95% CI 16.27-100.06), with very low evidence.

CONCLUSIONS

This systematic review and meta-analysis of observational studies and clinical trials that included children/adolescents with CKD found that cardiorespiratory fitness is severely reduced in this population and that exercise training may be an effective strategy for improvement. Given the low evidence certainty, additional high-quality trials are necessary.

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.

Nasogastric Tube Feeding in Infants on Peritoneal Dialysis

Enteral nutritional support is an important component of the care provided to infants receiving long-term peritoneal dialysis. In the majority of published experiences on this subject, the use of the nasogastric tube has facilitated the provision of required calorie and protein intake and resulted in an improved patient outcome. Advantages of the nasogastric route of nutritional support include the ease of administration, while recurrent emesis remains the most troublesome and frequent shortterm complication associated with its use. Impaired oralmotor development may also result from nonoral feeding and should be addressed throughout the course of tube feeding.

The outcome of infants with ESRD receiving CPD has markedly improved since the introduction of NG feedings as a regular component of dialysis patient care. While complications associated with NG feedings have been documented, the benefits associated with this route of nutritional supplementation have been great. Currently, an increasing number of infants/ young children on CPD are receiving supplemental nutrition with the use of the gastrostomy tube/button (31). However, the risks associated with this route of therapy in the CPD population, especially in terms of infection, are as yet not well defined (32). Once the risk/benefit ratio of gastrostomy tube/button placement is determined, future efforts should be directed towards better defining how the two routes of enteral nutritional support (e.g., NG tube, gastrostomy tube/button) may best complement one another.

Increase of the Bioavailabllity of Intraperitoneal Erythropoietin in Children on Peritoneal Dialysis by Administration in Small Dialysis Bags

Objective

To establish the effectivity of administration of erythropoietin intraperitoneally in a small amount of fluid in children with renal anemia on continuous ambulatory peritoneal dialysis (CAPD).

Design

Prospective study in which children with renal anemia on CAPD were treated with erythropoietin intraperitoneally, administered in a specially designed bag containing 50 mL NaCl 0.9%.

Setting

University hospital.

Patients

The patient population consisted of 9 children treated with CAPD and 1 treated with nightly intermittent peritoneal dialysis. The median age was 7.8 years (range 4.1 -15.2). Four of these children had not been treated with erythropoietin before (group A), and 6 had been treated with erythropoietin administered intraperitoneally in 250 mL of dialysis fluid (group B).

Interventions

Patients in group A started on a dose of approximately 300 units/kg per week (group A). Patients in group B received their previous dose. Do sage was adjusted to achieve a target hemoglobin level of 6.5 7.0 mmol/L (104 -112 g/L). Serum ferritin levels and transferrin saturation were monitored and iron supplementation was prescribed in the case of iron deficiency.

Main outcome measures

Weekly erythropoietin dose in relation to hemoglobin level.

Results

In group A, median hemoglobin level rose from 5.3 mmol/L (85 g/L) to 6.6 mmol/L (106 g/L) after 6 months of therapy, whereas the median erythropoietin dose decreased from 266 to 234 U/kg/week. In group B, hemoglobin levels remained stable and median erythropoietin dose decreased from 262 to 194 U/kg/week. One patient in this group, for unknown reasons, never responded to erythropoietin treatment. He was excluded from further analysis. In the remaining 5 patients the median cumulative erythropoietin dose was 3250 U/kg in the 3-month period prior to the start of the study and 2713 in the 3-month period starting 6 months after the beginning of the study. This difference of 17% was statistically significant using a Wilcoxon test (p < 0.05).

Conclusion

Intraperitoneal administration of erythropoietin in a small amount of dialysis fluid leads to a decrease in the required dose.

Exercise Capacity in Pediatric Patients with End-Stage Renal Disease

Objective

To evaluate the correlation between exercise capacity and hemoglobin in pediatric patients with end-stage renal disease (ESRD) treated with automated peritoneal dialysis (APD) and hemodialysis.

Design

Prospective case-control study and retrospective review.

Setting

Dialysis summer camp and Children's Mercy Hospital exercise laboratory.

Participants

Prospective evaluation conducted with 14 patients (9 males, mean age 14.5 ± 2.5 years) who received either home APD (5 patients) or in-center hemodialysis (9 patients), and 8 healthy age-matched controls. Retrospective data derived from 10 children (7 males, mean age 12.3 ± 3.3 years), all of whom received APD.

Intervention

Maximal treadmill evaluation conducted with each patient and control. The hemoglobin value of each patient was also assessed.

Main Outcome Measures

Comparison of the following data generated during treadmill protocol: peak heart rate, blood pressure, oxygen saturation, treadmill time, oxygen consumption (VO2), ventilation (Ve), oxygen consumption at anaerobic threshold (VO2 AT), and respiratory exchange ratio.

Results

The hemoglobin value of the current patient group (12.8 ± 1.6 g/dL) was significantly greater than the previously studied patients (10.5 ± 1.1 g/dL) ( p = 0.001). Treadmill time, VO2, and VO2 AT were significantly lower in both groups of dialysis patients compared to the control subjects ( p < 0.05). No differences were noted in any of these variables when comparing these two groups of dialysis patients only.

Conclusion

The exercise capacity of pediatric dialysis patients is significantly poorer than that of healthy children, an outcome apparently related to factors other than normalization of the hemoglobin value.

Management of anemia with erythropoietic-stimulating agents in children with chronic kidney disease

Anemia management is an important component of the care provided to children with chronic kidney disease (CKD) and influences both morbidity and mortality risk. The introduction of recombinant human erythropoietin to the treatment regimen three decades ago revolutionized the therapy and significantly decreased the need for repeated blood transfusions and exposure to associated risks. Recent data on the efficacy and complications associated with erythropoietic-stimulating agent (ESA) usage has, however, prompted a reassessment of treatment-related recommendations. This review will address these recommendations, in addition to describing pediatric outcomes associated with current ESAs and presenting information on alternative ESAs, many of which will likely soon be incorporated into clinical practice.

Exercise for children with chronic kidney disease and end-stage renal disease

It is well known that adults suffering from chronic kidney disease (CKD) experience muscle wasting and excessive fatigue, which results in a reduced exercise capacity and muscle weakness compared to their healthy counterparts, but research suggests that this can be improved through exercise. There is very limited data available regarding exercise tolerance in children with CKD and even less on the effects of exercise training programs. However, the available evidence does suggest that like adults, children also suffer from poor exercise capacity and reduced muscle strength, although the reasons for these limitations remain unclear. Studies that have attempted to implement exercise training programs in pediatric CKD populations have experienced high dropout rates, suggesting that the approach used to implement such programs in children needs to be different from the approach used for adults. This review summarizes the current knowledge regarding exercise capacity and muscle strength in children with CKD, the methods used to perform these assessments, and the possible causes of physical limitations. The results of exercise training studies, and the potential reasons as to why training programs have proved relatively unsuccessful are also discussed.

Six-minute walking test in children with ESRD: discrimination validity and construct validity

The six-minute walking test (6MWT) may be a practical test for the evaluation functional exercise capacity in children with end-stage renal disease (ESRD). The aim of this study was to investigate the 6MWT performance in children with ESRD compared to reference values obtained in healthy children and, secondly, to study the relationship between 6MWT performance with anthropometric variables, clinical parameters, aerobic capacity and muscle strength. Twenty patients (13 boys and seven girls; mean age 14.1 +/- 3.4 years) on dialysis participated in this study. Anthropometrics were taken in a standardized manner. The 6MWT was performed in a 20-m-long track in a straight hallway. Aerobic fitness was measured using a cycle ergometer test to determine peak oxygen uptake (V O(2peak)), peak rate (W(peak)) and ventilatory threshold (VT). Muscle strength was measured using hand-held myometry. Children with ESRD showed a reduced 6MWT performance (83% of predicted, p < 0.0001), irrespective of the reference values used. The strongest predictors of 6MWT performance were haematocrit and height. Regression models explained 59% (haematocrit and height) to 60% (haematocrit) of the variance in 6MWT performance. 6MWT performance was not associated with V O(2peak), strength, or other anthropometric variables, but it was significantly associated with haematocrit and height. Children with ESRD scored lower on the 6MWT than healthy children. Based on these results, the 6MWT may be a useful instrument for monitoring clinical status in children with ESRD, however it cannot substitute for other fitness tests, such as a progressive exercise test to measure V O(2peak) or muscle strength tests.

Exercise capacity and physical fitness in pediatric dialysis and kidney transplant patients

Studies of exercise capacity in children with chronic kidney disease (CKD) are limited. We tested 25 pediatric kidney transplant (TX) recipients and 15 pediatric dialysis (DX) patients. Nine children in the DX group received kidney transplants and were retested 3 months following surgery (pre/post). Testing involved treadmill testing with measurement of peak oxygen uptake (VO(2peak)), muscle strength, body composition (percent fat), and "field" tests of physical fitness using the FITNESSGRAM, which included the PACER test. Values obtained were compared with gender- and age-based criterion-referenced standards [healthy fitness zone (HFZ)]. The previous day physical activity recall (PDPAR) was used to assess physical activity participation. There were no differences between TX and DX subjects for VO(2peak) and muscle strength measurements, and all values were below the normative values. The TX group achieved significantly higher PACER scores, but only one TX and no DX subjects achieved the HFZ for the PACER test. No improvement in any measures were observed from pre- to post-TX in the nine subjects tested, except for a significant increase in percent fat, which negatively affected the change in muscle strength and VO(2peak). All subjects were physically inactive, with less than 10% of nonschool time being physical activity participation. Pediatric patients with CKD had low exercise capacity, were physically inactive, and gained significant fat weight following TX. Counseling and encouragement for more physical activity is warranted as a part of routine medical care in these children.

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.

Morbidity and mortality in children with anemia at initiation of dialysis

Studies in adult dialysis patients have identified anemia as a risk factor for patient morbidity and mortality. Limited comparable outcome data are available from children. We used the database from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) to identify patients <18 years of age who initiated dialysis (hemodialysis and peritoneal dialysis) between 1992 and 2001 with no prior history of dialysis or transplantation. A Cox proportional hazards model was used to evaluate the association between anemia (hematocrit <33%) at 30 days post initiation of dialysis and patient mortality. The association between anemia and prolonged hospitalization was also evaluated. Of the 1,942 patients (male 56%), 68% were anemic on day 30. One hundred and seventy-one patient deaths were reported over the 9-year observation period. The multivariate analysis demonstrated anemia to be associated with a 52% higher risk of death (adjusted relative risk 1.52, 95% confidence interval 1.03-2.26, P=0.037). Cardiopulmonary disease was the primary reported cause of death associated with anemia, accounting for 22% of cases. The presence of anemia was also associated with an increased risk for prolonged hospitalization, irrespective of dialysis modality. In conclusion, the presence of anemia 1 month after initiation of dialysis iis associated with an increased risk of prolonged hospitalization and death in pediatric patients. Further studies should ascertain whether anemia per se increases the risk of death or whether it is a marker for other conditions that shorten patient survival, such as chronic inflammation or recurrent infection.

Growth retardation in children with chronic renal failure

Growth retardation is a major obstacle to full rehabilitation of children with chronic renal failure (CRF). Several factors have been identified as contributors to impaired linear growth and they include protein and calorie malnutrition, metabolic acidosis, growth hormone resistance, anemia, and renal osteodystrophy. Although therapeutic interventions such as the use of recombinant human growth hormone, recombinant human erythropoietin, and calcitriol have made substantial contributions, the optimal therapeutic strategy remains to be defined. Indeed, growth failure persists in a substantial proportion of children with renal failure and those treated with maintenance dialysis. In addition, the increasing prevalence of adynamic lesions of renal osteodystrophy and its effect on growth have raised concern about the continued generalized use of calcitriol in children with CRF. Recent studies have shown the critical roles of parathyroid hormone-related protein (PTHrP) and the PTH/PTHrP receptor in the regulation of endochondral bone formation. The PTH/PTHrP receptor mRNA expression has been shown to be down-regulated in kidney and growth plate cartilage of animals with renal failure. Differences in the severity of secondary hyperparathyroidism influence not only growth plate morphology but also the expression of selected markers of chondrocyte proliferation and differentiation in these animals. Such findings suggest potential molecular mechanisms by which cartilage and bone development may be disrupted in children with CRF, thereby contributing to diminished linear growth.

Exercise evaluation of children with end-stage renal disease

The use of exercise testing in the assessment and management of various pediatric disorders has increased significantly during the past three decades. With age-appropriate equipment and exercise protocols, a well-trained and enthusiastic staff can evaluate patients as young as 3 to 4 years of age. Pediatric exercise testing may be conducted using either a cycle ergometer or a treadmill. The decision of which method to use is based on the parameters to be evaluated during the test, physical stature of the child, administrator preference, and availability of equipment in the laboratory. For children with renal disease, who are often short and may have poor leg muscle mass, the treadmill is used most often. The exercise testing protocols should use slow initial speeds and no grade, increase in small increments, and have stages of 1 to 2 minutes' duration. The benefits of testing in children with renal disorders include its ability to provide valuable information regarding the overall functional capacity of the patient, efficacy of pharmacological or surgical interventions, and outcome of rehabilitation programs.

Optimal care of the pediatric end-stage renal disease patient on dialysis

This manuscript is an effort on behalf of the American Society of Pediatric Nephrology to provide recommendations designed to optimize the clinical care of pediatric patients with end-stage renal disease (ESRD). Although many of the recommendations are evidenced-based with the supporting data being derived from a variety of sources, including patient registries, others are opinion-based and derived from the combined clinical experience of the authors. In all cases, it is recommended that the decision to initiate dialysis should be made only after an assessment of a combination of biochemical and clinical characteristics. Irrespective of the choice of dialysis modality (hemodialysis v peritoneal dialysis), dialysis efficacy should be measured regularly, and the dialysis prescription should be designed to achieve target clearances. Attention to dialysis adequacy, control of osteodystrophy, nutrition, and correction of anemia is mandatory, because all may influence patient outcome in terms of growth, cognitive development, and school performance. Finally, the availability of a multidisciplinary team of pediatric specialists is desirable to provide all facets of pediatric ESRD care, including renal transplantation, in an optimal manner. Future clinical research efforts intended to address topics such as dialysis adequacy, anemia management, and growth should be encouraged.

The impact of the Dialysis Outcomes Quality Initiative Guidelines on the care of the pediatric end-stage renal disease patient

The National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) Guidelines for hemodialysis and peritoneal dialysis adequacy, management of vascular access, and management of anemia are based primarily on evidence derived from the experience of adult dialysis patients. However, these Guidelines can also be used to improve the care of children with end-stage renal disease (ESRD). Some of the guidelines are directly applicable to pediatric dialysis patients, such as the preferential use of the internal jugular vein for placement of a central venous catheter for dialysis. Other Guidelines, such as targets for adequacy of hemodialysis and peritoneal dialysis, serve as minimal standards of care for children with little supporting data specific to pediatrics. The importance of early referral and proactive care for children and adults with chronic renal failure is emphasized in all of the Guidelines. Optimum care should include early discussion of transplantation and choice of dialysis modality, preservation of sites for future vascular access, and early attention to anemia and nutrition. Clinical algorithms should be developed to implement the current Guidelines while data are generated to support modification of any of the recommendations for children.

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.

New hormones in the therapeutic arsenal of chronic renal failure. Growth hormone and erythropoietin

Although the benefits of rhGH and r-HuEPO therapy in children with CRF and on dialysis are already significant, further study of these new additions to the therapeutic arsenal remains necessary. Data on the final adult height achieved in patients who receive rhGH are extremely important information that is as yet unavailable. The risks and benefits of raising the target hematocrit to a "normal" value in patients receiving r-HuEPO remains under study. Only when these and other issues are soundly evaluated will the full impact of these medications be understood.

Low-dose subcutaneous recombinant erythropoietin in children with chronic renal failure. Australian and New Zealand Paediatric Nephrology Association

In a multicentre trial, low-dose subcutaneous recombinant human erythropoietin (r-Hu EPO) was evaluated in 22 children aged 4 months to 16 years with anaemia of chronic renal failure over a 12-month period. A starting dosage of 50 U/kg twice weekly was given until a target haemoglobin of 9-11 g/dl was achieved. The dosage was increased by 50 U/kg per week, each 4 weeks, if the haemoglobin did not increase by 1 g/dl per month. When the target haemoglobin was achieved, the same weekly dosage was given as a single injection. After 10 weeks, the mean haemoglobin increased from 6.7 +/- 0.7 to 9.6 +/- 1.9 g/dl (P < 0.001) and the haematocrit from 19.8% +/- 2.4% to 29.3% +/- 6.3% (P < 0.001). By 4 months the target haemoglobin was achieved in 19 patients on 50 U/kg twice weekly and 1 patient on 75 U/kg twice weekly. Two children with severe renal osteodystrophy failed to respond to 95 U/kg and 150 U/kg twice weekly. The maintenance weekly dose of r-Hu EPO in 9 children over 4-12 months ranged between 45 and 125 U/kg. The Wechsler intelligence score increased in 11 children from 92 +/- 16 to 97 +/- 17 over the 12-month period (P = 0.007). No adverse effects were recorded. A starting dose of r-Hu EPO of 50 U/kg subcutaneously twice weekly is recommended as effective and safe for the majority of children with anaemia of chronic renal failure.

Effect of lidocaine on the hematopoietic properties of recombinant human erythropoietin in the uremic rat

Subcutaneous injections of recombinant human erythropoietin (rHuEPO) produce considerable pain which can result in noncompliance. As a prelude to an investigation of the possible use of local anesthetics as additives to subcutaneous rHuEPO, we examined the effect of the addition of lidocaine on the erythropoietic properties of rHuEPO. Two weeks after 5/6 nephrectomy, 22 rats were randomly assigned to the following groups: normal saline, rHuEPO, lidocaine, and rHuEPO plus lidocaine. Injections were given three times a week for 2 weeks. No change in hematocrit was observed in the saline and lidocaine groups. The hematocrit of the rHuEPO rats increased from 44.5 +/- 1.4% (mean +/- SD) to 61.6 +/- 2.1% (P < 0.0005), and that of the rHuEPO plus lidocaine group from 42.8 +/- 4.3% to 63.9 +/- 3.0% (P < 0.005), with no difference between the groups. We conclude that the combination of rHuEPO plus lidocaine is as effective as rHuEPO alone in increasing the hematocrit of rats with chronic renal failure.

Non-cardiac benefits of human recombinant erythropoietin in end stage renal failure and anaemia

Recombinant human erythropoietin (r-HuEpo) is now available to correct the anaemia of end stage renal failure. The clinical consequences of increasing the haemoglobin concentration in children on dialysis are incompletely documented; a placebo controlled study is essential when assessing subjective changes, for example in appetite or other aspects of quality of life. A single blind, placebo controlled crossover study in 11 children with end stage renal failure was performed to assess the clinical benefits resulting from correction of anaemia. Ten of the 11 children completed 36 weeks of the study and seven completed both 24 week limbs. Subcutaneous administration of r-HuEpo twice a week resulted in an increase in haemoglobin concentration, from 73 to 112 g/l. This was associated with an objective improvement in exercise tolerance, and a subjective improvement in physical performance and health, and better school attendance. No consistent effect was seen on appetite, growth, psychosocial functioning, biochemical control, or peritoneal dialysis efficiency. A small but clinically unimportant increase in systolic and diastolic blood pressure was seen in five children. One child on antihypertensive treatment required an increase in dosage during r-HuEpo while another child required a reduction in treatment. These findings, together with the important cardiac benefits previously described during r-HuEpo treatment, support the use of r-HuEpo in all children with end stage renal failure and anaemia.

Treatment of renal anemia by subcutaneous erythropoietin in children with preterminal chronic renal failure

Eleven children aged 0.6-17 years with preterminal chronic renal failure and anemia (mean serum creatinine concentration 4.8 mg/dl; mean hemoglobin concentration 7.9 g/dl) were treated with sc injections of recombinant human erythropoietin (EPO, initial dose 150 U/kg/week) over a mean period of 13 months. When a target hemoglobin concentration of 11.5-13.5 g/dl was reached, the dose was adapted. Iron deficiency was corrected. Hemoglobin concentration increased by > 2 g/dl in all patients within 14-119 (mean 45) days. The last maintenance dose ranged between 75 and 300 (mean 133) U/kg/week. No major adverse effects were observed, except for hypertension which occurred in about half of the patients and necessitated interruption of EPO in one child with advanced renal failure. Additional antihypertensive drugs were given to five patients. Body height increased in two patients by 0.6 and 1.3 SDS/year, respectively. In six patients with a mean observation period of 14 months before and 16 months after the start of EPO, the mean slope of the reciprocal serum creatinine concentration curve improved slightly (p = 0.05). The proposed schedule appears to be safe for the treatment of renal anemia in most pre-dialysis patients. Frequent monitoring of hemoglobin, blood pressure, serum creatinine and ferritin is required.

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.