Antibody-mediated pure red cell aplasia in a dialysis patient receiving darbepoetin alfa as the sole erythropoietic agent

Successful Treatment of Antibody-mediated Pure Red Cell Aplasia Induced by Continuous Erythropoietin Receptor Activator with Prednisolone

Pure red cell aplasia (PRCA) associated with erythropoiesis-stimulating agents (ESAs), which were first reported in 1998, usually occurs with subcutaneous administration of epoetin alfa (Eprex^®). Improvements in ESA storage, handling, and administration methods have reduced the PRCA incidence. Continuous erythropoietin receptor activator (CERA) is a third-generation ESA that is rarely reported to induce PRCA. We herein report a case of CERA-induced PRCA presenting with positive anti-erythropoietin (EPO) and anti-CERA antibodies, which was successfully treated with prednisolone. Clinicians should be aware of the possibility of antibody-mediated PRCA induced by an ESA in CKD patients with anemia with reticulocytopenia and low serum EPO levels.

Acquired Pure Red Cell Aplasia Following Recombinant Erythropoietin (Darbepoetin-alfa) Therapy

Acquired pure red cell aplasia (PRCA) following use of recombinant erythropoietin (rEPO) is distinctly rare and sporadically reported in the literature. We discuss a case of PRCA following the usage of rEPO (darbepoetin-α) during the management of anemia of chronic kidney disease in an elderly male subject with review of literature and a brief insight into proposed pathophysiologic mechanism, diagnosis, and management.

Pure red cell aplasia and anti-erythropoietin antibodies in patients on hemodialysis: a report of two cases and a literature review

Introduction:

Anemia is a frequent multifactorial complication of CKD seen in patients on dialysis derived mainly from impaired erythropoietin (EPO) production. A less common cause of anemia in individuals with CKD is pure red cell aplasia (PRCA) secondary to the production of anti-EPO antibodies.

Objective:

This paper aimed two describe two cases of PRCA secondary to the production of anti-EPO antibodies including choice of treatment, patient progression, and a literature review.

Materials:

This study included the cases of two patients with CKD on hemodialysis with severe anemia in need of specific investigation and management.

Results:

Patient 1 with CKD secondary to hypertension treated with EPO for 7 months showed persistent decreases in hemoglobin (Hb) levels despite the subcutaneous administration of increasing doses of EPO; the patient required recurring blood transfusions. Workup and imaging tests were negative for the main causes of anemia in individuals with CKD on dialysis. Patient 2 with CKD secondary to adult polycystic kidney disease had been taking EPO for 2 years. The patient developed severe abrupt anemia the month he was started on HD, and required recurring transfusions to treat the symptoms of anemia. Workup and imaging findings were inconclusive. Specific laboratory tests confirmed the patients had anti-EPO antibodies. After six months of immunosuppressant therapy (corticosteroids + cyclosporine) the patients were stable with Hb > 9.0 g/dl.

Conclusion:

PRCA is a rare condition among patients on dialysis treated with rhEPO and should be considered as a possible cause of refractory anemia. Treating patients with PRCA may be challenging, since the specific management and diagnostic procedures needed in this condition are not always readily available.

Pure red cell aplasia due to antibody against erythropoietin in hemodialysis patients

Background

Anemia is a common complication of chronic renal failure due to reduce erythropoietin production by kidneys. Anemia treated with recombinant human erythropoietin (rHu-EPO). Pure red cell aplasia (PRCA) due to antibody productionagainst rHu-EPO is a rare but major complication of this drug.

Objectives

The aim of this study was to determine the prevalence of PRCA due to antibodies in dialysis patients with resistant anemia who received erythropoietin.

Patients and Methods

We studied 128 under maintenance hemodialysis patients more than 3 month in Kashan. In patients with anemia who received erythropoietin with dose requirements based on weight and anemia and without any another cause for anemia, evaluate for PRCA and anti-rHu-EPO antibody level were measured by ELISA.

Results

In this research, 75 patients (58.6%) were male and 53 patients (41.4%) were female. The mean age of the patients was 59.05 ± 16.66 years. The result of analysis showed that 55 (43%) patients had anemia with hemoglobin level less than 10 mg/dL. Only 3 patients had PRCA and antibodies against erythropoietin in serum. There were no correlation between age, gender, cause of renal failure, hemodialysis duration, hemoglobin level, rHu-EPO dose and levels of anti-rHu-EPO antibody serum value.

Conclusions

The result of this study indicated that administration of rHu-EPO in dialysis patients afflicted to kidney failure may cause PRCA especially through intravenous injection. However, this change is not statistically significant.

Incidence of erythropoietin antibody-mediated pure red cell aplasia: the Prospective Immunogenicity Surveillance Registry (PRIMS)

BACKGROUND

Subcutaneous administration of Eprex(®) (epoetin alfa) in patients with chronic kidney disease (CKD) was contraindicated in the European Union between 2002 and 2006 after increased reports of anti-erythropoietin antibody-mediated pure red cell aplasia (PRCA). The Prospective Immunogenicity Surveillance Registry (PRIMS) was conducted to estimate the incidence of antibody-mediated PRCA with subcutaneous administration of a new coated-stopper syringe presentation of Eprex(®) and to compare this with the PRCA incidence with subcutaneous NeoRecormon(®) (epoetin beta) and Aranesp(®) (darbepoetin alfa).

METHODS

PRIMS was a multicentre, multinational, non-interventional, parallel-group, immunogenicity surveillance registry. Adults with CKD receiving or about to initiate subcutaneous Eprex(®), NeoRecormon(®) or Aranesp(®) for anaemia were enrolled and followed for up to 3 years. Unexplained loss or lack of effect (LOE), including suspected PRCA, was reported, with antibody testing for confirmation of PRCA.

RESULTS

Of the 15 333 patients enrolled, 5948 received Eprex(®) (8377 patient-years) and 9356 received NeoRecormon(®)/Aranesp(®) (14 286 patient-years). No treatment data were available for 29 patients. Among 23 patients with LOE, five cases of PRCA were confirmed (Eprex(®), n = 3; NeoRecormon(®), n = 1; Aranesp(®), n = 1). Based on exposed time, PRCA incidence was 35.8/100 000 patient-years (95% CI 7.4-104.7) for Eprex(®) versus 14.0/100 000 patient-years (95% CI 1.7-50.6) for NeoRecormon(®)/Aranesp(®). The incidence of PRCA with Eprex(®) was not significantly different versus comparator ESAs (rate ratio: 2.56; 95% CI 0.43-15.31). An analysis based on observed time produced similar findings.

CONCLUSION

This large, prospective registry demonstrates that PRCA is rare with subcutaneous administration of either the new coated-stopper syringe presentation of Eprex(®), or NeoRecormon(®) or Aranesp(®).

Differentiating factors between erythropoiesis-stimulating agents: an update to selection for anaemia of chronic kidney disease

Erythropoiesis-stimulating agents (ESAs) have become a hallmark of anaemia therapy in patients with chronic kidney disease (CKD). Although different ESAs are available for the treatment of renal anaemia, each nephrologist should select a single ESA for an individual patient. Epoetin alfa and epoetin beta have been used 1-3 times weekly but extended-interval dosing up to every 4 weeks is also effective in a substantial majority of CKD patients. However, the epoetin dose necessary to achieve or maintain target haemoglobin (Hb) levels increases substantially as the dosing interval increases. Subcutaneous administration of short-acting ESAs is more effective than the intravenous route of administration. Darbepoetin alfa and the continuous erythropoietin receptor activator (CERA) have been developed as a treatment for anaemia with extended administration intervals (every 2 weeks and every 4 weeks, respectively). Dose requirements for these long-acting ESAs are independent of the route of administration. Patents of short-acting ESAs have expired, which has opened the field for biosimilars. Epoetin biosimilars approved by the European Medicines Agency (EMA) or the US Food and Drug Administration (FDA) have been shown to have a comparable efficacy and safety profile to their originators. An alarming increase in pure red cell aplasia (PRCA) in Thailand with follow-on epoetins manufactured in Asia (but also those manufactured in Latin America) indicates that stringent country-specific approval and pharmacovigilance protocols for ESAs manufactured in non-North American and non-EU European countries are urgently needed. Two PRCA cases occurring with subcutaneous HX575 (one certain, one likely) indicate that chances of inducing a more immunogenic product are unpredictable, even with a biosimilar epoetin approved under the EMA biosimilar approval pathway. Phase III clinical trials with peginesatide, a pegylated synthetic peptide-based ESA without any homology to erythropoietin raised safety concerns in non-dialysis CKD patients but not in dialysis patients.

Tungsten-induced denaturation and aggregation of epoetin alfa during primary packaging as a cause of immunogenicity

Purpose

Following two cases of neutralizing antibodies to epoetin alfa in an investigational clinical study, a small number of individual syringes of two drug product batches were found to contain unusually high levels of aggregation at the end of the clinical trial.

Methods

We undertook an extensive analytical approach to determine the root-cause of the increased aggregation in the affected batches.

Results

Soluble tungsten was found in the syringes, most likely derived from the pins used to manufacture the syringes. Spiking of epoetin alfa with sodium polytungstate or an extract of tungsten pins used to manufacture the syringes induced the formation of aggregates, both dimers that appeared to be covalently linked by disulphide bonds as well as higher-order aggregates. Sodium polytungstate had also a strong denaturing effect on the protein.

Conclusions

We propose tungsten-mediated unfolding and aggregation of epoetin alfa in pre-filled syringes as a potential root cause for increased immunogenicity. This finding may be more broadly applicable to this and other classes of therapeutic proteins.

2008 Japanese Society for Dialysis Therapy: guidelines for renal anemia in chronic kidney disease

The Japanese Society for Dialysis Therapy (JSDT) guideline committee, chaired by Dr Y. Tsubakihara, presents the Japanese guidelines entitled "Guidelines for Renal Anemia in Chronic Kidney Disease." These guidelines replace the "2004 JSDT Guidelines for Renal Anemia in Chronic Hemodialysis Patients," and contain new, additional guidelines for peritoneal dialysis (PD), non-dialysis (ND), and pediatric chronic kidney disease (CKD) patients. Chapter 1 presents reference values for diagnosing anemia that are based on the most recent epidemiological data from the general Japanese population. In both men and women, hemoglobin (Hb) levels decrease along with an increase in age and the level for diagnosing anemia has been set at <13.5 g/dL in males and <11.5 g/dL in females. However, the guidelines explicitly state that the target Hb level in erythropoiesis stimulating agent (ESA) therapy is different to the anemia reference level. In addition, in defining renal anemia, the guidelines emphasize that the reduced production of erythropoietin (EPO) that is associated with renal disorders is the primary cause of renal anemia, and that renal anemia refers to a condition in which there is no increased production of EPO and serum EPO levels remain within the reference range for healthy individuals without anemia, irrespective of the glomerular filtration rate (GFR). In other words, renal anemia is clearly identified as an "endocrine disease." It is believed that defining renal anemia in this way will be extremely beneficial for ND patients exhibiting renal anemia despite having a high GFR. We have also emphasized that renal anemia may be treated not only with ESA therapy but also with appropriate iron supplementation and the improvement of anemia associated with chronic disease, which is associated with inflammation, and inadequate dialysis, another major cause of renal anemia. In Chapter 2, which discusses the target Hb levels in ESA therapy, the guidelines establish different target levels for hemodialysis (HD) patients than for PD and ND patients, for two reasons: (i) In Japanese HD patients, Hb levels following hemodialysis rise considerably above their previous levels because of ultrafiltration-induced hemoconcentration; and (ii) as noted in the 2004 guidelines, although 10 to 11 g/dL was optimal for long-term prognosis if the Hb level prior to the hemodialysis session in an HD patient had been established at the target level, it has been reported that, based on data accumulated on Japanese PD and ND patients, in patients without serious cardiovascular disease, higher levels have a cardiac or renal function protective effect, without any safety issues. Accordingly, the guidelines establish a target Hb level in PD and ND patients of 11 g/dL or more, and recommend 13 g/dL as the criterion for dose reduction/withdrawal. However, with the results of, for example, the CHOIR (Correction of Hemoglobin and Outcomes in Renal Insufficiency) study in mind, the guidelines establish an upper limit of 12 g/dL for patients with serious cardiovascular disease or patients for whom the attending physician determines high Hb levels would not be appropriate. Chapter 3 discusses the criteria for iron supplementation. The guidelines establish reference levels for iron supplementation in Japan that are lower than those established in the Western guidelines. This is because of concerns about long-term toxicity if the results of short-term studies conducted by Western manufacturers, in which an ESA cost-savings effect has been positioned as a primary endpoint, are too readily accepted. In other words, if the serum ferritin is <100 ng/mL and the transferrin saturation rate (TSAT) is <20%, then the criteria for iron supplementation will be met; if only one of these criteria is met, then iron supplementation should be considered unnecessary. Although there is a dearth of supporting evidence for these criteria, there are patients that have been surviving on hemodialysis in Japan for more than 40 years, and since there are approximately 20 000 patients who have been receiving hemodialysis for more than 20 years, which is a situation that is different from that in many other countries. As there are concerns about adverse reactions due to the overuse of iron preparations as well, we therefore adopted the expert opinion that evidence obtained from studies in which an ESA cost-savings effect had been positioned as the primary endpoint should not be accepted unquestioningly. In Chapter 4, which discusses ESA dosing regimens, and Chapter 5, which discusses poor response to ESAs, we gave priority to the usual doses that are listed in the package inserts of the ESAs that can be used in Japan. However, if the maximum dose of darbepoetin alfa that can currently be used in HD and PD patients were to be used, then the majority of poor responders would be rescued. Blood transfusions are discussed in Chapter 6. Blood transfusions are attributed to the difficulty of managing renal anemia not only in HD patients, but also in end-stage ND patients who respond poorly to ESAs. It is believed that the number of patients requiring transfusions could be reduced further if there were novel long-acting ESAs that could be used for ND patients. Chapter 7 discusses adverse reactions to ESA therapy. Of particular concern is the emergence and exacerbation of hypertension associated with rapid hematopoiesis due to ESA therapy. The treatment of renal anemia in pediatric CKD patients is discussed in Chapter 8; it is fundamentally the same as that in adults.

Drug safety profile of darbepoetin alfa for anemia of chronic kidney disease

Anemia of chronic kidney disease due to deficiency of erythropoietin is common and has clinical consequences. Erythropoiesis stimulating agents including darbepoetin alfa (DA) are effective in correcting anemia. DA is generally well tolerated and has side effect profile similar to recombinant human erythropoietin. It has a long half-life permitting infrequent dosing. DA has been tested extensively in preclinical and clinical studies and significant experience has accumulated in clinical practice. Global safety profile of DA must consider recent data indicating worse survival, poor cardiovascular outcomes and thrombotic risks of targeting near normal hemoglobin levels and administering high doses of erythropoiesis stimulating agents. Strategies to achieve and maintain a reasonable, individualized target hemoglobin level with minimal variations in hemoglobin level are needed.

Antibody-mediated pure red cell aplasia (PRCA) on switching from darbepoetin alfa to epoetin beta: what are the implications?

We report the development of antibody-mediated pure red cell aplasia (PRCA) in a 63-year-old man with end-stage renal disease following a switch from darbepoetin alfa to epoetin beta. Haemoglobin levels began to decrease 6 months after the switch. Increasing the epoetin beta dose produced no response and regular blood transfusions were required; PRCA was confirmed and epoetin beta was discontinued. The patient responded positively to immunosuppression; after 2 months on prednisone and cyclophosphamide, haemoglobin levels stabilized and no further transfusions were required. This case highlights the difficulty in establishing a cause-effect relationship where more than one erythropoiesis-stimulating agent is involved.

Darbepoetin alfa for anemia in chronic kidney disease

Anemia of chronic kidney disease (CKD) is common, yet it is often under-recognized and undertreated, with serious adverse consequences. It is highly responsive to treatment with erythropoiesis-stimulating agents (ESAs). Darbepoetin alfa is a hyperglycosylated ESA that has a lower affinity to the erythropoietin receptor but a longer half-life than recombinant human erythropoietin, irrespective of administration by a subcutaneous or intravenous route. Owing to its pharmacokinetic characteristics, darbepoetin alfa has been used in extended dosing intervals ranging from once every week to once every 4 weeks in CKD patients on dialysis, as well as in CKD patients not on dialysis. Darbepoetin alfa has been shown to be safe and effective in clinical trials. The safety profile of darbepoetin alfa is similar to that of recombinant human erythropoietin. While target hemoglobin levels in CKD anemia remain debatable, treatment of anemia with ESAs has the proven benefits of reducing transfusions and improving quality of life. Darbepoetin alfa has the potential to simplify the treatment of CKD anemia with many advantages, including infrequent dosing, improved patient convenience and compliance, and decreased healthcare resource utilization.

Epoetin-induced pure red cell aplasia: diagnosis and treatment

PURPOSE OF REVIEW

Antibody-mediated pure red cell aplasia is now recognized as a rare complication of erythropoiesis-stimulating agent therapy. The incidence of this adverse effect peaked in 2002, but new cases still appear sporadically. The aim of this review is to discuss the latest opinions regarding the detection and management of this condition.

RECENT FINDINGS

The diagnosis of classical erythropoiesis-stimulating agent induced pure red cell aplasia is made by a constellation of clinical features, including severe transfusion-dependent anaemia, reticulocytopenia, low or absent erythroblasts in the bone marrow, and the presence of circulating antierythropoietin antibodies. Recently, some cases have been reported in which the bone marrow findings show red cell hypoplasia rather than aplasia; this may represent earlier presentations of the same condition.

SUMMARY

Management of pure red cell aplasia as a complication of erythropoiesis-stimulating agent therapy consists of stopping the drug and implementing an immunosuppressive regimen to reduce or abolish erythropoietin antibody production. A recent animal study suggested that a possible alternative strategy may be to administer a novel peptide-based erythropoietin receptor agonist called Hematide that does not cross react with antierythropoietin antibodies, and will allow ongoing stimulation of erythropoiesis; this is the subject of a current clinical trial.

Pure red cell aplasia induced by erythropoiesis-stimulating agents

Pure red cell aplasia in patients who are treated for anemia of chronic kidney disease with erythropoiesis-stimulating agents such as epoetin was first reported in 1998. Although the incidence of pure red cell aplasia peaked in 2002, it remains important for nephrologists to know how to investigate a suspected case of pure red cell aplasia and how to identify other causes of hyporesponsiveness to erythropoiesis-stimulating agents, which account for the vast majority of such cases. The authors reviewed the current status of information in the literature and drew on their personal experiences with patients regarding the diagnosis and management of epoetin-induced pure red cell aplasia. The mechanism for development of epoetin-induced pure red cell aplasia remains unconfirmed. It generally occurs after the production of neutralizing anti-erythropoietin antibodies. Elucidation of a suspected pure red cell aplasia case requires a systematic approach, beginning with simple measurements such as blood cell counts, because most cases of erythropoiesis-stimulating agent hyporesponsiveness are attributable to other causes. If these criteria indicate that the patient's response to erythropoiesis-stimulating agent therapy is very poor, then bone marrow examination and measurement of anti-erythropoietin antibodies is justified. If pure red cell aplasia is confirmed, then cessation of erythropoiesis-stimulating agent therapy and initiation of immunosuppressive therapy are recommended. Continued study of epoetin-induced pure red cell aplasia is needed to help nephrologists prevent or manage future cases and will have implications for the use of other protein-based therapeutic agents.

Pathophysiology of anemia and erythrocytosis

An increasing understanding of the process of erythropoiesis raises some interesting questions about the pathophysiology, diagnosis and treatment of anemia and erythrocytosis. The mechanisms underlying the development of many of the erythrocytoses, previously characterised as idiopathic, have been elucidated leading to an increased understanding of oxygen homeostasis. Characterisation of anemia and erythrocytosis in relation to serum erythropoietin levels can be a useful addition to clinical diagnostic criteria and provide a rationale for treatment with erythropoiesis stimulating agents (ESAs). Recombinant human erythropoietin as well as other ESAs are now widely used to treat anemias associated with a range of conditions, including chronic kidney disease, chronic inflammatory disorders and cancer. There is also heightened awareness of the potential abuse of ESAs to boost athletic performance in competitive sport. The discovery of erythropoietin receptors outside of the erythropoietic compartment may herald future applications for ESAs in the management of neurological and cardiac diseases. The current controversy concerning optimal hemoglobin levels in chronic kidney disease patients treated with ESAs and the potential negative clinical outcomes of ESA treatment in cancer reinforces the need for cautious evaluation of the pleiotropic effects of ESAs in non-erythroid tissues.

Anti-erythropoietin antibody-mediated pure red cell aplasia in a living donor liver transplant recipient treated for hepatitis C virus

After liver transplantation, reinfection of the newly engrafted liver with hepatitis C virus is essentially universal in patients who are viremic at the time of transplantation. Treatment with interferon preparations with or without ribavirin is recommended in patients with marked histologic injury; however, hematologic toxicity associated with therapy has been reported, which is usually treated with growth factor support, including erythropoietin analogues. We present the first reported case of anti-erythropoietin antibody-mediated pure red cell aplasia arising in the setting of hepatitis C virus therapy in a patient who underwent living donor liver transplantation.

Hematide is immunologically distinct from erythropoietin and corrects anemia induced by antierythropoietin antibodies in a rat pure red cell aplasia model

OBJECTIVE

To evaluate the potential of Hematide, a PEGylated, synthetic peptide-based erythropoiesis-stimulating agent that is in clinical development for the treatment of anemia associated with chronic kidney disease and cancer, to correct antierythropoietin antibody-associated pure red cell aplasia (PRCA).

MATERIALS AND METHODS

The binding of anti-Hematide antibodies (mouse, rabbit, and monkey) to recombinant human erythropoietin (rHuEPO) and of anti-rHuEPO antibodies (mouse, goat, rat, and human) to Hematide were evaluated. An anti-EPO antibody-mediated anemia rat model was developed by subcutaneously administering rHuEPO to rats three times weekly for 4 weeks. Sixty percent of the animals developed PRCA as characterized by severe anemia, reduced reticulocytes, anti-EPO antibodies, and limited bone marrow erythroid precursors. The effect of Hematide administration on the PRCA rats was evaluated.

RESULTS

Antibodies to EPO do not cross react with Hematide and, conversely, antibodies to Hematide do not cross react with EPO. Hematide corrected antibody-induced anemia in a rat PRCA model.

CONCLUSIONS

The data support the potential of Hematide to correct anti-EPO antibody-associated PRCA in humans. In addition, the data suggest a negligible risk for development of anti-EPO antibody-induced PRCA secondary to Hematide administration.