Variations of recombinant human erythropoietin application in hemodialysis patients

Switching from subcutaneous to intravenous erythropoietin α in haemodialysis patients requires a major dose increase

BACKGROUND

A change in the licensing arrangements for the use of erythropoietin alpha in haemodialysis patients has required a switch in the route of administration from subcutaneous (SC) to intravenous (IV). Previous work suggested that the IV route was less efficacious but studies since the enforced switch have not confirmed this.

METHODS

We studied haemoglobin levels and the mean weekly dose of erythropoietin alpha in 86 haemodialysis patients at monthly intervals over the 6 month period before and after a change in the route of administration of erythropoietin alpha from SC to IV. Changes in other parameters known to be associated with erythropoietin response were also monitored.

RESULTS

Mean haemoglobin level fell following the switch from 11.9 g/dl+/-1.4 at baseline to 11.3 g/dl+/-1.4 at 1 month (P = 0.001) and to a trough of 11.0 g/dl+/-1.3 at 2 months (P<0.001) before partial recovery to 11.4 g/dl+/-1.2 (P = 0.007) at 6 months. Mean weekly dose of erythropoietin after 2 months was significantly higher than baseline (8791 IU+/-5314 vs 8035 IU+/-4893). The dose continued to increase and by 6 months was 10605 IU (P<0.001), 32% higher than baseline. There was a small reduction in residual renal function, which was an independent predictor of change in dose requirement. There was a small increase in parathyroid hormone levels, but no change in serum ferritin, dosing frequency, total Kt/V, serum albumin, normalised protein catabolic rate, C-reactive protein, hospitalization rate and dialyser reuse rate.

CONCLUSIONS

Switching from SC to IV erythropoietin alpha caused a significant fall in haemoglobin levels in the first 2 months. This was partially reversed by 6 months at the expense of a 32% dose increase in the dose of erythropoietin alpha by 6 months. The economic impact may be considerable.

Meta-analysis of subcutaneous versus intravenous epoetin in maintenance treatment of anemia in hemodialysis patients

BACKGROUND

Clinical and pharmacokinetic studies have shown that target hemoglobin or hematocrit levels can be maintained using a reduced recombinant human erythropoietin (epoetin) dosage by switching from intravenous (IV) to subcutaneous (SC) administration.

METHODS

We conducted a meta-analysis of comparative studies of epoetin administered IV versus SC to assess the relative costs of these administration routes. Twenty-seven prospective clinical studies involving 916 patients were included in the analysis. The average difference between IV and SC doses of epoetin and average difference in drug costs between administration routes were determined.

RESULTS

The average reduction in dose in patients treated with SC versus IV epoetin was 48 IU/kg/wk (P < 0.001), representing an average annual cost savings with SC administration of US $1,761 +/- $1,080 (SD) per patient. The difference between SC and IV doses was similar in both parallel- and crossover-design studies. A retrospective US survey showed a dose reduction of 26 IU/kg/wk (P < 0.001) with SC administration, translating to an annual savings of $946 per patient.

CONCLUSION

This study indicates that the cost of epoetin is reduced substantially when administered SC in comparison to IV. Recommendations of current US and European guidelines, which encourage the use of SC administration, not only have a sound rationale in terms of efficacy and safety, but also have a sound economic basis.

Controversies in selection of epoetin dosages. Issues and answers

Epoetin (recombinant human erythropoietin) is now a widely available though expensive treatment for the anaemia of chronic renal failure, and is effective in more than 95% of patients. Complications of epoetin in this context include hypertension in a third of cases, including hypertensive encephalopathy in a few, and thrombosis of shunts or vascular access devices. Fears that epoetin would cause progression of renal failure have not generally been confirmed, but hyperkalaemia may be a problem in the initial phase of treatment. Epoetin is up to twice as effective when administered subcutaneously rather than intravenously. Responding patients will normally do so within 3 months of starting epoetin. Failures to respond are usually due to iron deficiency or intercurrent disease. Other diseases associated with anaemia and an inappropriately low serum epoetin level include prematurity, the anaemia of cancer and rheumatoid arthritis. The baseline serum endogenous erythropoietin may provide a guide to response in some of these cases. Some encouraging results are being published. Situations where the serum erythropoietin levels are normal or elevated where epoetin has been employed include boosting of haematocrit presurgery as an adjunct to autologous blood donation, treatment of anaemic patients with myelodysplastic syndromes, and improvement of athletic performances.

Improvement of erythropoietin-induced hypertension in hemodialysis patients changing the administration route

The aim of the present study has been to assess whether the administration of recombinant human erythropoietin (rHuEPO) by the subcutaneous (sc) route improves blood pressure control of dialysis patients with erythropoietin-induced hypertension. We have selected 13 hemodialysis patients who have remained hypertensive after more than one year of i.v. rHuEPO treatment (mean 22 +/- 8 months, range 12-35 months). Hematocrit, rHuEPO dose, predialysis mean arterial pressure and antihypertensive drug dosage had remained constant during the last six months. These patients were switched to sc administration of rHuEPO thrice weekly, with reduction of rHuEPO dose by one third (from 149 +/- 56 to 98 +/- 53 IU/kg/week). Concomitantly, predialysis mean arterial pressure significantly decreased (113.1 +/- 7.8 during the last month of i.v. administration vs 107.8 +/- 9.8 during the first month of sc administration, p < 0.05, and 105.5 +/- 5.2 mmHg at six months, p < 0.05), without relevant changes in hematocrit. After six months of sc administration, 5 patients remained normotensive without drugs and 6 out of the remaining 8 patients required antihypertensive drugs at lower doses. Administration of rHuEPO by sc route decreases dose requirements and improves blood pressure control in hypertensive patients when treated by i.v. route.

Differences in intravenous and subcutaneous application of recombinant human erythropoietin: a multicenter trial

The aims of this clinical study were to compare the maintenance doses for intravenous (i.v.) and subcutaneous (SC) administration of recombinant human erythropoietin (rhEPO) and to investigate whether there is any difference in the increase of the packed cellular volume (PCV) per week under i.v. and SC administration of rhEPO from two production sites (Genetics Institute, Cambridge, USA; and Boehringer Mannheim, Penzberg, Germany). A total of 90 patients suffering from end-stage renal disease were included in the study. All patients had already been treated for at least 6 months with chronic hemodialysis. The study was carried out as a randomized, multicenter parallel group comparison study with a 1-week pretreatment phase, a subsequent 8-week double-blind phase, and a final open phase. The final open phase consisted of a correction phase and a maintenance phase. The production site had no influence on the PCV increase per week, and there were no differences with respect to tolerability. The median rhEPO dose required to maintain the target PCV of 30 to 35 vol.% was 33 U/kg body weight three times a week in the i.v. group compared with 22 U/kg in the SC group (i.e., an average of 30% less with SC administration). Development or aggravation of hypertension under rhEPO therapy was observed, especially during the correction phase and more frequently in the SC group than in the i.v. group. During the maintenance phase, there was no essential difference between the two groups.

Identification of the component part in an epoetin alfa preparation that causes pain after subcutaneous injection

The subcutaneous administration of epoetin alfa preparations may cause pain at the injection site. To identify the pain-causing substance in these formulations we performed two double-blind, placebo-controlled, randomized order, cross-over studies. Differences in pain experienced after subcutaneous injection of an epoetin alfa solution and its vehicle were assessed in 36 patients. The vehicle and its component parts, albumin and citrate, were compared in 36 volunteers. Normal saline served as a placebo control in both studies. Pain scores were obtained from visual analogue pain scales with no divisions and from five point verbal descriptive pain scales. Both the epoetin alfa solution and its vehicle caused significantly more pain than normal saline (P < 0.0001) in the patients studied. In volunteers the pain scores with the vehicle or its citrate component were significantly higher (P < 0.0001) when compared with normal saline or with the albumin component of the vehicle. In conclusion, the local pain experienced after subcutaneous administration of epoetin alfa preparations is mainly caused by the citrate component of the buffered solution. Epoetin alfa and the albumin component of the preparation do not play a role in this phenomenon.

Erythropoietin in cardiac surgery

Erythropoietin is the primary growth factor for red blood cells. A glycoprotein hormone synthesized by the kidneys, erythropoietin serves to increase red blood cell production in response to tissue hypoxia. It exerts its effect by increasing the numbers of erythroid progenitor cells in the bone marrow, and by increasing the rate at which their development is accomplished. With the introduction of recombinant erythropoietin in 1987, an important pharmacological agent became available for the manipulation of erythropoiesis. While used primarily for the treatment of the anemia of renal failure, recombinant erythropoietin has also shown usefulness in treating other types of anemias in which the endogenous erythropoietin response is insufficient. Perioperative use of the drug grew as a natural extension of this, and erythropoietin has been applied to correct preoperative anemia, augment autologous blood donation, and improve postoperative red cell recovery. Analysis of these perioperative clinical studies reveals success in these areas, but it also reveals that closer attention to the physiology of the natural response, and to the pharmacology of the recombinant product, might significantly improve results. Such an improvement in efficacy is both desirable and necessary when use of the drug is viewed in the setting of today's changing health care environment. By optimizing dosing schedules and targeting the drug to those most at risk for red cell transfusion, recombinant erythropoietin will likely become an important tool in efforts to achieve the elusive goal of bloodless cardiac surgery.

Intravenous versus subcutaneous dosing of epoetin: a review of the literature

Recombinant human erythropoietin (epoetin) is approved to be administered by the intravenous (i.v.) or subcutaneous (SC) route. Several studies have been conducted and published that compare the relative pharmacokinetics and efficacy of the IV and SC routes. An analysis of the methodology and results of these studies reveals that the data have been somewhat contradictory and highly variable. However, most investigations have concluded that the SC route is associated with a decreased dose requirement in the correction and/or maintenance phase. To justify a switch from the i.v. to the SC route, it is important to consider the practical implications, including patient and staff acceptance, as well as the financial aspects. Regardless of the route of administration, dose titration must be individualized based on the patient's response to epoetin therapy, red blood cell turnover rate, and iron status. More studies are needed to develop a standardized cost-effective method for epoetin dosing in patients on dialysis.

Adverse events of subcutaneous recombinant human erythropoietin therapy: results of a controlled multicenter European study

In a controlled European multicenter study, clinical tolerance of subcutaneously administered recombinant human erythropoietin (rh-EPO) therapy and its influence on the course of illness in 362 hemodialyzed patients (162 males, 200 females) from 16 European dialysis centers was studied. Of these, 181 patients served as a control group in the first year and received rh-EPO therapy in the second year. Of the 837 adverse events that occurred, 277 were classified as serious and 560 as nonserious. Thirty-two deaths have been reported for the study population: 18 in the control group and 14 in the therapy group. The individual analysis of the serious adverse events including death demonstrates a protective effect of rh-EPO on the high-risk cardiovascular situation of dialysis patients. Hypertension was no problem, and under rh-EPO therapy an increase in resistance to infection was observed. Subcutaneous rh-EPO treatment might have an even better safety profile than intravenous application.