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Unrelated-donor bone marrow transplantation for Philadelphia chromosome-positive chronic myelogenous leukemia in children.

PURPOSE
Bone marrow transplantation (BMT) for Philadelphia chromosome-positive (Ph1) chronic myelogenous leukemia (CML) results in a 55% to 64% disease-free survival (DFS) rate in 20% to 30% of cases with a matched-sibling donor (MSD). Studies that include primarily adults with CML, using unrelated-donor (URD) BMT, have expanded this option to those without an MSD. We review and compare the efficacy of URD and MSD BMT in children with Ph1 CML.


PATIENTS AND METHODS
Eleven children with URD BMTs were reviewed and compared with 11 children with MSD BMTs for Ph1 CML. Among the URD BMT recipients, there were three with fully matched marrows and 10 with advanced CML. The median time from diagnosis to transplant was 2.6 years. Among the MSD BMT recipients, 11 had fully matched marrows and five had advanced CML. The median time from diagnosis to BMT was 0.7 years. All received non-T-depleted marrows after cyclophosphamide and fractionated total-body irradiation.


RESULTS
Both groups had similar engraftment times. Late graft failure occurred in two URD patients. Graft-versus-host disease (GVHD), > or = grade II, was similar in both groups (77% for URD BMT, 45% for MSD BMT), although more severe acute disease and more persistent chronic disease was seen in the URD group. The Kaplan-Meier estimate of DFS was 45% +/- 15% (SE) and 78% +/- 14% (SE) in the URD and MSD groups, respectively, at 3 years. All had Karnofsky scores of more than 70%, except one URD patient debilitated from GVHD.


CONCLUSION
CML is eventually fatal to all patients without BMT. The high survival rate seen among children who receive a URD BMT, despite several adverse factors, opens this important therapeutic option to those without an MSD.