Rabbit Antithymocyte Globulin Versus Campath-1H for Treating Severe Aplastic Anemia
Status:
Completed
Trial end date:
2016-02-05
Target enrollment:
Participant gender:
Summary
Severe aplastic anemia, characterized by pancytopenia and a hypocellular bone marrow, is
effectively treated by immunosuppressive therapy, usually a combination of antithymocyte
globulin (ATG) and cyclosporine (CsA). Survival rates following this regimen are equivalent
to those achieved with allogeneic stem cells transplantation. However, approximately 1/3 of
patients will not show blood count improvement after ATG/CsA. General experience and small
pilot studies have suggested that such patients may benefit from further immunosuppression.
Furthermore, analysis of our own clinical data suggest that patients with poor blood count
responses to a single course of ATG, even when transfusion-independence is achieved, have a
markedly worse prognosis than patients with robust hematologic improvement. The management of
such cases is uncertain.
This study will enroll patients who are either refractory to h-ATG (continued severe
pancytopenia) or who have only modest improvement in blood counts (weak hematologic
responders) to receive a further immunosuppressive therapy, delivered either as rabbit ATG
(Thymoglobulin, r-ATG) or a humanized monoclonal antibody to T-cells, alemtuzumab (Campath-1H
). Primary endpoint will be response rate at 3 months defined as no longer meeting criteria
for severe aplastic anemia. Relapse, robustness of hematopoietic recovery at 3 months,
survival and clonal evolution to paroxysmal nocturnal hemoglobinuria (PNH), myelodysplasia
and acute leukemia will be the secondary endpoints.