Rechallenge with intravenous recombinant human erythropoietin can be successful following the treatment of anti-recombinant erythropoietin associated pure red cell aplasia.

Anti recombinant human erythropoietin (r-HuEpo) associated pure red cell aplasia (PRCA) is an immunologic adverse effect of using subcutaneous r-HuEpo. Immunosuppressive agents have been suggested as treatment of this serious complication. After the reversal of anti-r-HuEpo antibody, the patients continue to have renal anemia and require long-term blood transfusion, albeit less frequently than when the antibody is positive. It is controversial whether re-challenging the patients with r-HuEpo is appropriate because re-challenging may cause the reappearance of the antibody. To balance the risk of antir-HuEpo antibody reappearance and longterm blood transfusion complications, we re-challenged r-HuEpo in five anti-r-HuEpo associated PRCA cases after a successful reversal of antibody using prednisolone in combination with cyclophosphamide. The rechallenge was performed intravenously since there were no reports of anti-r-HuEpo associated PRCA cases using this administration route. The duration after the reversal of antibody was 2.4 months before the re-challenge. Two patients were immediately re-challenged as soon as the antibodies reversed. After rechallenge with intravenous r-HuEpo, all patients responded to r-HuEpo: target level of Hb was maintained, blood transfusion was not required, and anti-r-HuEpo was consistently negative. All patients were followed for at least 6 months after re-challenge. Our data suggest that re-challenge with intravenous r-HuEpo can successfully treat anti- r-HuEpo associated PRCA.