Roxadustat Improves Erythropoietin Antibody-Mediated Pure Red Cell Aplasia in a Patient with Hemodialysis.

Anemia is a common complication of chronic kidney disease (CKD). Recombinant human erythropoietin (rHu-EPO) is used extensively in patients with CKD. However, anti-erythropoietin (anti-EPO) antibody has been reported during rHu-EPO treatment, which causes pure red cell aplasia (PRCA). We presented a case of 75-year-old man, who underwent hemodialysis for 2 years. He developed PRCA during rHu-EPO treatment. The rHu-EPO was immediately discontinued, and the patient was given roxadustat treatment. After 6 months of roxadustat treatment, the anti-EPO antibody was disappeared, and hemoglobin recovered normal range. The results suggest that roxadustat can be used to treat patients with anti-EPO antibody-mediated PRCA without immunosuppressive therapy.

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.

Baseline Soluble Anti-erythropoietin Antibody Level Is an Independent Associated Factor for Follow-Up Erythropoietin Demand in Maintenance Dialysis Patients With End-Stage Renal Disease: A Prospective Cohort Study.

Aims: The aim of this study was to identify the predictive role of baseline anti-erythropoietin (anti-EPO) antibody levels in follow-up EPO demand in maintenance dialysis patients with end-stage renal disease (ESRD). Methods: Baseline routine blood parameters, clinical data, dialysis-related parameters, EPO, anti-EPO antibody, and anti-EPO-receptor antibody were also measured. Differences in the abovementioned variables were compared among four intervals of the EPO demand index (EDI). Further univariate and adjusted logistic regression analyses were performed to identify the independent predictors for higher EPO demand. Results: The predialysis potassium ion concentration was significantly higher in the fourth quartile (Q4) population than in the other three populations (p < 0.05). Furthermore, the anti-EPO antibody level showed significant differences among the four intervals (p = 0.006). The baseline anti-EPO antibody level was correlated with the follow-up EDI (r 2 = 0.0377, p = 0.030). Furthermore, the follow-up EDI was significantly higher in the anti-EPO antibody-positive group (p = 0.02). Age (OR = 1.071, p = 0.005), ferritin (OR = 1.001, p = 0.038), potassium ion concentration before dialysis (OR = 2.781, p = 0.012), dialysis duration (OR = 1.025, p = 0.030), and anti-EPO antibody level (OR = 7.694, p = 0.004) were potential predictors for higher EPO demand. After adjustment, age (OR = 1.072, p = 0.026), potassium ion concentration before dialysis (OR = 3.425, p = 0.013), and EPO level (OR = 5.27, p = 0.007) were independent predictors for higher EDI demand. Conclusion: The baseline anti-EPO antibody level combined with an older age and a higher predialysis potassium ion concentration are independent predictors for a higher follow-up EPO demand in maintenance dialysis patients with ESRD.

Resolution of epoetin-induced pure red cell aplasia, successful re-challenge with roxadustat.

The application of erythropoietin (EPO) can bring about a rare but serious complication called anti-EPO antibody-mediated pure red cell aplasia (PRCA). Once the disease is diagnosed, EPO administration should be stopped immediately. However, after the removal of the anti-EPO antibody, treating anaemia in these patients with chronic renal disease with EPO therapy is difficult, as restarting EPO therapy risks the recurrence of anti-EPO antibody-mediated PRCA. A 26-year-old man with anaemia related to renal failure, who was administered recombinant human EPO subcutaneously, developed anti-EPO antibody-mediated PRCA. After removal of antibodies by treatment with corticosteroids and cyclosporine, therapy for anaemia of chronic renal disease with roxadustat achieved good results. Roxadustat is a new type of drug for the treatment of anaemia, and it can stimulate endogenous EPO within or near the physiologic range and increase haemoglobin levels.

Comparison of different immunoassay methods to detect human anti-drug antibody using the WHO erythropoietin antibody reference panel for analytes.

Development of an appropriate assay to detect anti-drug antibody (ADA) is important for assessing immunogenicity to therapeutic protein products. However, characterizing ADA assay methods is difficult because human ADA as a reference standard is not available in most cases. We compared the analytical performance of three ligand-binding assay methods for ADA, namely, surface plasmon resonance (SPR), electrochemiluminescence (ECL), and biolayer interferometry (BLI) methods, by using the anti-erythropoietin (EPO) monoclonal antibody reference panel developed by the World Health Organization (WHO) in 2015. Dose-dependent binding responses were observed for all nine anti-EPO antibodies in the anti-EPO panel by the SPR and BLI methods. In contrast, the ECL method did not clearly detect binding of low-affinity anti-EPO antibodies. Regarding IgG2 and IgM antibodies derived from the same clone, IgG2 exhibited a higher binding response in the SPR assay, whereas the IgM binding response was higher than that of IgG2 in the ECL assay. In the case of the BLI method, there was no consistent pattern observed in the binding responses of IgG2 or IgM. Results of the anti-EPO antibody reference panel, which contains a variety of monoclonal antibodies, indicated that the ability to detect ADAs differed among these assay methods. Therefore, with ligand-binding assays, differences in assay platforms can affect the sensitivity and other characteristics of assays to detect ADAs. These results show that understanding the analytical performance of ADA assays is important for an appropriate assessment of immunogenicity. Our study also indicated the benefits of using the established human ADA reference panel to assess the assay methods for ADA detection.

Pure red cell aplasia induced by anti-erythropoietin antibodies, well-controlled with tacrolimus.

Anti-erythropoietin (anti-EPO) antibody-related pure red cell aplasia (PRCA) is a rare but serious complication that can occur during the administration of erythropoiesis-stimulating agents. Treatment with the calcineurin inhibitor cyclosporine has shown benefits in patients with anti-EPO PRCA. The efficacy of tacrolimus, another calcineurin inhibitor, in patients with anti-EPO PRCA has not been determined. The present report is the first our knowledge to describe the successful treatment of a patient with anti-EPO PRCA using tacrolimus. A 73-year-old man was markedly anemic 8 months after starting epoetin beta treatment. He was diagnosed with anti-EPO PRCA. Cyclosporine was started, but he experienced side effects. He was switched from cyclosporine to tacrolimus. No side effects were observed, and his anti-EPO PRCA was improved 6 months later, despite the persistence of anti-EPO antibodies. Tacrolimus was continued until the disappearance of the antibodies. Following the cessation of tacrolimus, PRCA did not relapse. Antibody remained detectable at the time of clinical remission, indicating that immunosuppressive therapy should be continued while monitoring the antibody titer. When the antibody titer decreases to the negative range, cessation of the immunosuppressive therapy does not result in disease relapse.