Cord Blood Transplantation from Unrelated Donors Versus Stem Cell Transplantation from HLA-Identical Sibling in Adults with Philadelphia-Positive Acute Lymphoblastic Leukemia

Allogeneic stem cell transplantation (allo-SCT) is considered the best post-remission therapy for patients with Ph+ALL. However, the application of this procedure is limited by the availability of suitable HLA-compatible donors. Umbilical cord blood transplantation (UCBT) from unrelated donors has emerged as an alternative approach for patients lacking an HLA-matched donor. This study compares the clinical outcome of 36 adults with Ph+ALL who received either UCBT from unrelated donors (n = 25) or bone marrow or peripheral blood stem cell transplantation (BMT/PSCT) from HLA-matched sibling donors (n = 11) at a single institution. From June 1999 to August 2010, all consecutive patients with Ph+ALL, except one who received total body irradiation, received busulfan, thiotepa, and cyclophosphamide or fludarabine as myeloablative conditioning regimen. Antithymocyte globulin was added in UCBT patients. All patients received cyclosporine as graft-versus-host disease prophylaxis, combined prednisone or mycophenolate mofetil in UCBT or methotrexate in matched-sibling allo-SCT. Median age was 33 years (range, 16-54) and 21 (58%) were males. At time of transplantation, 28 (78%), 3 (8%) and 5 (14%) were in first complete remission (CR), second or further CR and more advanced phase of the disease, respectively. Patient and disease characteristics were similar in both groups. Except for one patient undergoing UCBT that experienced primary graft failure, all remaining patients engrafted. Myeloid engraftment was faster in BMT/PSCT than UCBT (median 12 days vs 20 days; p< 0.01). With a median follow-up of surviving patients of 41 months (range 15-114), the 4-year CI of NRM for UCBT and BMT/PSCT recipients was 36% and 9%, respectively (p = 0.1), and the CI of relapse 22% and 64%, respectively (p = 0.15). Disease-free survival at 4 years was 42% in UCBT and 27% in matched-sibling allo-SCT recipients; (p = 0.6). Our data suggest that for patients with Ph+ALL, UCBT from unrelated donors is a reasonable approach with efficacy similar to that of BMT/PSCT from HLA-identical sibling.