Description
OUTLINE: Patients are assigned to 1 of 2 arms.
ARM I: Patients aged 6 months through 30 years old receive myeloablative conditioning comprising fludarabine intravenously (IV) over 30 minutes on days -8 to -6, cyclophosphamide IV on days -7 and -6, and undergo high-dose TBI twice daily (BID) on days -4 to -1. Patients then undergo UCBT on day 0. Patients undergo blood sample collection throughout the study. Patients undergo echocardiography (ECHO) or multigated acquisition scan (MUGA) and diagnostic imaging during screening and as clinically indicated on study. Patients also undergo blood sample collection throughout the study and bone marrow aspirate during screening and on study.
ARM II: Patients aged 6 months through 65 years old receive myeloablative conditioning comprising fludarabine IV over 30-60 minutes on days -6 to -2, cyclophosphamide IV on day -6, thiotepa IV over 2-4 hours on days -5 and -4, and middle-intensity TBI once daily (QD) on days -2 and -1. Patients undergo ECHO or MUGA and diagnostic imaging during screening and as clinically indicated on study. Patients also undergo blood sample collection throughout the study and bone marrow aspirate during screening and on study.
All patients receive GVHD prophylaxis comprising cyclosporine IV over 1 hour every 8 or 12 hours, then cyclosporine orally (PO) (if tolerated), on days -3 to 100 with taper on day 101. Patients also receive mycophenolate mofetil IV every 8 hours on days 0 to 7 and then PO (if tolerated) three times daily (TID) on days 8-30. Mycophenolate mofetil is tapered to BID on day 30 or 7 days after engraftment if there is no acute GVHD, and then tapered over 2-3 weeks beginning on day 45 (or 15 days after engraftment if engraftment occurred > day 30) after engraftment if there continues to be no evidence of acute GVHD.
After completion of study treatment, patients are followed up at day 180, 1 year, and 2 years.