Fludarabine-based Conditioning for Severe Aplastic Anemia (BMT CTN 0301)

The purpose of the current study is to continue to optimize conditioning regimens in high-risk patients with severe aplastic anemia transplanted with marrow from HLA-compatible unrelated donors. Specifically, the study will determine whether the addition of fludarabine to the conditioning regimen previously described by Deeg et al. will permit a reduction in the CY dose, to a point where sustained hematopoietic engraftment and survival are maintained (or improved), while the frequency of major regimen-related toxicity (RRT) and early deaths is reduced.