Summary
This phase II trial tests whether treosulfan, fludarabine, and rabbit antithymocyte globulin (rATG) work when given before a blood or bone marrow transplant (conditioning regimen) to cause fewer complications for patients with bone marrow failure diseases. Chemotherapy drugs, such as treosulfan, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Fludarabine may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. rATG is used to decrease the body's immune response and may improve bone marrow function and increase blood cell counts. Adding treosulfan to a conditioning regimen with fludarabine and rATG may result in patients having less severe complications after a blood or bone marrow transplant.