Fludarabine-Based Conditioning for Allogeneic Marrow Transplantation from HLA-Compatible Unrelated Donors in Severe Aplastic Anemia

Severe aplastic anemia is a blood disorder in which the bone marrow stops working, and produces few or no blood cells (such as white and red blood cells and platelets). Left untreated, aplastic anemia can cause death from infection or bleeding. A bone marrow transplant may therefore be performed to replace the patient’s abnormal bone marrow with functioning marrow.

The bone marrow may come from a related donor or an unrelated donor whose marrow matches that of the recipient. In this study, investigators are evaluating a new approach to bone marrow transplantation for aplastic anemia in which the marrow is coming from an unrelated donor.

Before the transplant, the patient’s immune function and abnormal bone marrow are suppressed using a combination of medications (usually anti-thymocyte globulin and cyclophosphamide) and total body irradiation. However, this “conditioning” regimen can cause side effects, especially due to the cyclophosphamide. In this study, researchers are adding a new drug called fludarabine to this conditioning regimen in hopes of reducing the dose of cyclophosphamide. They will determine what dose of cyclophosphamide should be used in the conditioning step when fludarabine is also used.