Eltrombopag for the Treatment of Refractory Pure RBC Aplasia after Major ABO Incompatible Hematopoietic Stem Cell Transplantation

Pure RBC aplasia (PRCS) is a well-recognized complication after allogeneic hematopoietic stem cell transplantation (HSCT). Many therapeutic options are available to treat this condition, including erythropoietin, rituximab, bortezomib, plasma exchange, immunoadsorption, donor lymphocyte infusion, mesenchymal stem cells, antithymocyte globulin, and high-dose steroids; however, treatment outcomes are often variable and can sometimes lead to disappointing results. In this brief article we report our experience with 2 patients with PRCA after major ABO-incompatible HSCT who were resistant to multiple therapeutic interventions and who eventually benefited from treatment with eltrombopag, a thrombopoietin mimetic approved by the US Food and Drug Administration for the treatment of patients with immune thrombocytopenic purpura or severe aplastic anemia refractory to immunosuppressive agents or not eligible for HSCT. Data from these 2 patients show that eltrombopag was effective in treating erythroid aplasia and transfusion dependence after HSCT in patients who did not benefit from multiple previous treatments. Moreover, eltrombopag was well tolerated, with only a transient thrombocytosis requiring dose adjustment and no evidence of clonal evolution. Based on the positive results obtained in these 2 patients, we suggest that eltrombopag may have a favorable effect on unilineage cytopenias such as PRCA. Further studies in a large proportion of patients are mandatory to confirm these preliminary results.