Erythropoietin-Mimetic Peptide Pegmolesatide Therapy for Pure Red Cell Aplasia in a Patient with Nondialysis-Dependent Type 1 Diabetic Nephropathy: A Case Report

Introduction: Pure red cell aplasia (PRCA) is a rare complication of erythropoietin (EPO) therapy, characterized by a severe deficiency in red blood cell production. There is no guideline on the treatment for PRCA because there have been too few cases to perform prospective cohort studies. The main treatments for PRCA include immediate cessation of EPO, restrictive transfusion, and immunosuppressive therapies. Case Description: A 35-year-old male patient with type 1 diabetic nephropathy was diagnosed with PRCA. Enarodustat and roxadustat were administered successively after discontinuation of EPO, but anemia did not improve, and the patient was maintained with weekly blood transfusions. Subsequently, the EPO-mimetic peptide pegmolesatide was administered, and the patient’s hemoglobin started to increase after 1 week and increased from 50 g/L to 92 g/L over approximately 3 months. Discussion: The new EPO-mimetic peptide pegmolesatide, which consists of 44 amino acids and has a completely different peptide chain structure from peginesatide and EPO (Fig 4), was independently developed in China. It can bind the EPO receptor with high selectivity and high affinity, and then promotes erythrocyte production efficiently. Importantly, pegmolesatide has no homology to the known sequences of endogenous or exogenous EPO. Thus, there is no cross-immune response between pegmolesatide and EPO. In addition, pegmolesatide rarely produces drug antibodies, attributed to the low immunogenicity.Based on these findings, we speculate that pegmolesatide can provide a safe, effective, and convenient therapeutic strategy for PRCA in Chinese patients with chronic kidney disease.