Pharmacokinetics of intravenous, intraperitoneal, and subcutaneous recombinant erythropoietin in patients on CAPD. A rationale for treatment

Erythropoietin Administration for Anemia Due to Chronic Kidney Disease - Subcutaneous OR Intravenous, What Do We Know So Far?

The prevalence of anemia in chronic kidney disease (CKD) patients is almost twice that of the normal population and its severity increases exponentially as the disease worsens, dramatically affecting the quality of an individual’s life. The advent of erythropoiesis stimulating agents (ESA) in the 1980s saw a revolutionary change in the treatment of anemia in CKD patients, drastically improving quality of life (QoL), overall health and reducing the need for blood transfusions. Numerous ESAs have been developed ever since and are in current use, with the primary routes of administration being intravenous (IV) and subcutaneous (SC) injections. Their use, however, has stirred significant controversy over the last two decades. Additionally, despite numerous studies and trials, the latest international recommendations for their use do not provide clear cut guidance with well-grounded evidence on the recommended route of administration for different sets of patients. Instead, this decision has mainly been left up to the physician’s discretion, whilst keeping certain key factors in mind. This review shall summarize, discuss and compare the findings of previous studies on various factors governing the two aforementioned routes of administration and identify areas that need further exploration.

Randomized trial of darbepoetin alfa for treatment of renal anemia at a reduced dose frequency compared with rHuEPO in dialysis patients

BACKGROUND

Darbepoetin alfa is a glycoprotein with a three-fold longer terminal half-life than recombinant human erythropoietin (rHuEPO). We aimed to determine whether darbepoetin alfa is as effective and well tolerated as rHuEPO for treating renal anemia in dialysis patients when administered at a reduced dose frequency.

METHODS

A total of 522 European and Australian hemodialysis and peritoneal dialysis patients receiving stable rHuEPO therapy by either the intravenous (IV) or subcutaneous (SC) route were randomized, open-label in a 1:2 ratio to continue rHuEPO or to receive an equivalent dose of darbepoetin alfa at a reduced dose frequency. Patients receiving rHuEPO once weekly changed to once every other week darbepoetin alfa, and those receiving rHuEPO two or three times weekly changed to once-weekly darbepoetin alfa. The doses of rHuEPO and darbepoetin alfa were titrated to maintain hemoglobin close to the patient's baseline level for up to 52 weeks. The primary endpoint was the change in hemoglobin between baseline and the evaluation period at weeks 25 to 32 of treatment.

RESULTS

The mean change in hemoglobin from baseline to the evaluation period was similar in the darbepoetin alfa (-0.03 g/dL; SE 0.11) and rHuEPO (-0.06 g/dL; SE 0.13) groups, and the difference between the two treatments was 0.03 g/dL (95% CI -0.16, 0.21). This was not a statistically significant or clinically relevant difference, despite the reduced frequency of darbepoetin alfa administration. At the end of the evaluation period, >/=95% of patients had their hemoglobin successfully maintained on their assigned dose frequency for darbepoetin alfa (once weekly and once every other week) and rHuEPO (once, twice and three times weekly). The safety profiles of darbepoetin alfa and rHuEPO were similar, and no antibodies to either treatment were detected.

CONCLUSIONS

Darbepoetin alfa maintains hemoglobin as effectively as rHuEPO, but with a reduced dose frequency.

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.

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.

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.