Allogeneic bone marrow transplantation for Philadelphia chromosome- positive chronic myelogenous leukemia in childhood

Allogeneic bone marrow transplantation (BMT) offers the only potential for long-term control of chronic myelogenous leukemia. From November 1992 to August 1994, we prospectively studied five pediatric patients with Philadelphia chromosome-positive chronic myelogenous leukemia, a unique finding in Taiwan, who were treated with allogeneic BMT at different stages of the disease. Their ages at diagnosis ranged from 2 to 10 years. Four donors were HLA-matched siblings and the other was an HLA-matched unrelated donor. All patients received busulfan (4 mg/kg/day for 4 days) followed by cyclophosphamide (60 mg/kg/day for 2 successive days) as the conditioning regimen. Engraftment was documented within 22 days after transplantation in all five patients. Two out of the four patients in the sibling donor group, both of whom had BMT in the first chronic phase, achieved event-free survival after follow-up for 41 months and 17 months. The other two patients, who had BMT in the second lymphoblastic crisis and the second chronic phase, died within 6 months after transplantation due to lymphoid blastic crisis and complication of cytomegaloviral pneumonitis, respectively. The patient who received marrow from the unrelated donor underwent BMT in the accelerated phase and died within 6 months after transplantation due to myeloid blastic crisis. In conclusion, allogeneic BMT performed in the first chronic phase of childhood Philadelphia chromosome-positive chronic myelogenous leukemia seems to have better results than BMT after the first chronic phase.