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

Challenges and recent advances in erythropoietin stability

Erythropoietin (EPO) is a pivotal hormone that regulates red blood cell production, predominantly synthesized by the kidneys and also produced by the liver. Since the introduction of recombinant human EPO (rh-EPO) in 1989 through recombinant DNA technology, the therapeutic landscape for anemia has been improved. rh-EPO's market expansion has been substantial, with its application extending across various conditions such as chronic kidney disease, cancer-related anemia, and other disorders. Despite its success, significant concerns remain regarding the stability of EPO, which is critical for preserving its biological activity and ensuring therapeutic efficacy under diverse environmental conditions. Instability issues, including degradation and loss of biological activity, challenge both drug development and treatment outcomes. Factors contributing to EPO instability include temperature fluctuations, light exposure, and interactions with other substances. To overcome these challenges, pharmaceutical research has focused on developing innovative strategies such as stabilizing agents, advanced formulation techniques, and optimized storage conditions. This review article explores the multifaceted aspects of EPO stability, examining the impact of instability on clinical efficacy and drug development. It also provides a comprehensive review of current stabilization strategies, including the use of excipients, lyophilization, and novel delivery systems.

Case Report: Roxadustat in Combination With Rituximab Was Used to Treat EPO-Induced Pure Red Cell Aplasia

Recombinant human erythropoietin (rHuEPO) is a drug given to patients who have low hemoglobin related to chronic kidney disease or other anemia-related diseases. Some patients who receive rHuEPO repeatedly develop anti-rHuEPO-neutralizing antibodies, leading to the occurrence of pure red cell aplasia (PRCA). PRCA associated with rHuEPO includes severe rHuEPO resistance, blood transfusion dependence, high serum ferritin, severe reticulocytopenia, and presence of anti-rHuEPO antibody. However, the optimal treatment of erythropoietin (EPO)-induced PRCA is unclear. Therapeutic options against it remain a major clinical challenge. Herein we report on 2 male patients with PRCA during rHuEPO treatment, who received a combination therapy of roxadustat plus rituximab but had completely different clinical outcomes. The results obtained in this study show that roxadustat in combination with rituximab could be one of the treatment options for EPO-induced PRCA, but the treatment efficacy can vary from one individual to another. Additionally, we recommend starting reticulocyte monitoring and immunosuppressive agent therapy as early as possible to shorten the course of the disease and improve the outcomes of the patients.