Unrelated donor bone marrow transplantation for children with acute myeloid leukemia beyond first remission or refractory to chemotherapy

Purpose Identify prognostic factors that influence outcome after unrelated donor bone marrow transplantation in children with acute myeloid leukemia (AML). Patients and Methods Included are 268 patients (age <= 18 years) with AML in second complete remission (n = 142), relapse (n = 90), or primary induction failure (n = 36) at transplantation. All patients received bone marrow grafts from an unrelated donor and a myeloablative conditioning regimen. Cox regression models were constructed to identify risk factors that influence outcome after transplantation. Results In this analysis, the only risk factor that predicted leukemia recurrence and overall and leukemia-free survival was disease status at transplantation. The 5-year probabilities of leukemia-free survival were 45%, 20%, and 12% for patients who underwent transplantation at second complete remission, relapse, and primary induction failure, respectively. As expected, risk of acute but not chronic graft-versus-host disease (GVHD) was lower with T-cell-depleted bone marrow grafts; T-cell-depleted grafts were not associated with higher risks of leukemia recurrence. We observed similar risks of leukemia relapse in patients with and without acute and chronic GVHD. Conclusion Children who underwent transplantation in remission had a superior outcome compared with children who underwent transplantation during relapse or persistent disease. Nevertheless, 20% of children who underwent transplantation in relapse are long-term survivors, suggesting that unrelated donor bone marrow transplantation is an effective therapy in a significant proportion of children with recurrent or primary refractory AML.