Autologous bone marrow transplantation versus intensive consolidation chemotherapy for acute myeloid leukemia in childhood

Background. The value of autologous bone marrow transplantation in the treatment of children with acute myeloid leukemia (AML) is unknown. We compared autologous bone marrow transplantation with intensive consolidation chemotherapy as treatments for children with AML in first remission. Methods. We induced remission with one course of daunorubicin, cytarabine, and thioguanine, followed by one course of high-dose cytarabine (3 g per square meter of body-surface area for six doses). Patients in remission after the second course of induction therapy were eligible for randomization. Between June 1988 and March 1993, 552 of 649 enrolled patients who could be evaluated (85 percent) entered remission. A total of 209 patients were not eligible for randomization; of the remaining 343 patients, 232 were randomly assigned to receive six courses of intensive chemotherapy (117 patients) or autologous transplantation (115 patients). Of the original 649 patients, 189, including 21 with Down's syndrome, were nonrandomly assigned to receive intensive chemotherapy. Results. The mean (±SE) rates of event-free survival and overall survival for the entire group at three years were 34±2.5 percent and 42±2.6 percent, respectively. For patients who were randomly assigned to one of the two treatment groups, the rates of event-free survival three years after randomization were not significantly different in the two groups when examined by intention-to-treat analysis: 36±5.8 percent for the intensive- chemotherapy group as compared with 38±6.4 percent for the autologous- transplantation group; and the relative risk of treatment failure for the chemotherapy group as compared with the autologous-transplantation group was 0.81 (P = 0.20 by the log-rank test; 95 percent confidence interval, 0.58 to 1.12). Overall survival at three years followed a similar pattern. There was a lower relapse rate (31 percent vs. 58 percent, P<0.001) but a higher rate of treatment-related mortality (15 percent vs. 2.7 percent, P = 0.005) in the group treated with autologous transplantation than in the intensive- chemotherapy group. The event-free survival at three years for the nonrandomized intensive-chemotherapy group was 39±5.1 percent, and for a contemporaneous group of patients each of whom received a histocompatible bone marrow transplant from a sibling, it was 52±8.0 percent. Conclusions. Treatment of children with AML in first remission with either autologous bone marrow transplantation or intensive chemotherapy prolongs event-free survival equally.