Patients receive fludarabine IV over 30 minutes on days -7 to -3 and cyclophosphamide IV over 1 to 2 hours on days -5 to -3. Patients undergo allogeneic peripheral blood stem cell transplantation on days 0-1. Patients then receive filgrastim (G-CSF) subcutaneously daily beginning on day 5 and continuing until blood counts recover.