Improved outcome with hematopoietic stem cell transplantation in a poor prognostic subgroup of infants with mixed-lineage-leukemia (MLL)-rearranged acute lymphoblastic leukemia: results from the Interfant-99 Study

To define a role for hematopoietic stem cell transplantation (HSCT) in infants with acute lymphoblastic leukemia and rearrangements of the mixed-lineage-leukemia gene (MLL(+)), we compared the outcome of MLL(+) patients from trial Interfant-99 who either received chemotherapy only or HSCT. Of 376 patients with a known MLL status in the trial, 297 (79%) were MLL(+). Among the 277 of 297 MLL(+) patients (93%) in first remission (CR), there appeared to be a significant difference in disease-free survival (adjusted by waiting time to HSCT) between the 37 (13%) who received HSCT and the 240 (87%) who received chemotherapy only (P = .03). However, the advantage was restricted to a subgroup with 2 additional unfavorable prognostic features: age less than 6 months and either poor response to steroids at day 8 or leukocytes more than or equal to 300 g/L. Ninety-seven of 297 MLL(+) patients (33%) had such high-risk criteria, with 87 achieving CR. In this group, HSCT was associated with a 64% reduction in the risk of failure resulting from relapse or death in CR (hazard ratio = 0.36, 95% confidence interval, 0.15-0.86). In the remaining patients, there was no advantage for HSCT over chemotherapy only. In summary, HSCT seems to be a valuable option for a subgroup of infant MLL(+) acute lymphoblastic leukemia carrying further poor prognostic factors. The trial was registered at www.clinicaltrials.gov as #NCT00015873 and at www.controlled-trials.com as #ISRCTN24251487.

Long-term results of the children's cancer group studies for childhood acute lymphoblastic leukemia 1983-2002: a Children's Oncology Group Report

The Children's Cancer Group enrolled 13 298 young people age <21 years on 1 of 16 protocols between 1983 and 2002. Outcomes were examined in three time periods, 1983-1988, 1989-1995, 1996-2002. Over the three intervals, 10-year event-free survival (EFS) for Rome/National Cancer Institute standard risk (SR) and higher risk (HR) B-precursor patients was 68 and 58%, 77 and 63%, and 78 and 67%, respectively, whereas for SR and HR T-cell patients, EFS was 65 and 56%, 78 and 68%, and 70 and 72%, respectively. Five-year EFS for infants was 36, 38, and 43%, respectively. Seminal randomized studies led to a number of important findings. Stronger post-induction intensification improved outcome for both SR and HR patients. With improved systemic therapy, additional intrathecal (IT) methotrexate effectively replaced cranial radiation. For SR patients receiving three-drug induction, iso-toxic substitution of dexamethasone for prednisone improved EFS. Pegylated asparaginase safely and effectively replaced native asparaginase. Thus, rational therapy modifications yielded better outcomes for both SR and HR patients. These trials provide the platforms for current Children's Oncology Group trials.