Stem Cell Transplantation for Genetic Diseases Treatment

PROTOCOL OUTLINE: Patients receive either cyclophosphamide and high dose total body irradiation (TBI) or busulfan and cyclophosphamide. Cyclophosphamide IV is given on days -5 and -4 and TBI on days -2, -1, and 0. Busulfan is given orally every 6 hours on days -9 through -6 and cyclophosphamide IV on days -5 through -2. Patients rest on day -1. Patients receive bone marrow infusion on day 0. For GVHD prophylaxis, patients receive methotrexate on day 1, then on days 3, 6, and 11. Cyclosporine IV begins on day -2 over 12 hours, followed by continuous infusion for 21 days. Then, oral doses of cyclosporine are given every 12 hours to patients who tolerate oral feeding. Cyclosporine is continued 6 months posttransplant, then tapered 10% per week and stopped. Patients who receive genotypically HLA nonidentical stem cells undergo additional GVHD prophylaxis with methylprednisolone (IV or PO) or its equivalent every 12 hours on days 3 to day 100. Dose is then tapered as tolerated over 1 month. Patients who receive cord blood stem cells receive methylprednisolone instead of methotrexate for GHVD prophylaxis. Methylprednisolone is given 3 times daily beginning on day 5 and continuing until day 17. Then, methylprednisolone is tapered 10% per week as clinically tolerated. To accelerate engraftment, patients receive filgrastim IM daily beginning on day +1 and continuing until ANC equals 5000.