Risk-Adapted Treatment for Acute Lymphoblastic Leukemia: Findings from St. Jude Children’s Research Hospital

Data from St. Jude Total Therapy Study XI were analyzed to identify clinical and biologic features with prognostic significance. Results of this analysis, along with information available in the literature, led us to redefine lower-risk acute lymphoblastic leukemia (ALL) by the following features: DNA index between 1.16 and 1.60, or age 1-9 years plus white blood cell count (WBC)<50 x 109/1; absence of CNS leukemia, testicular leukemia, T-cell immunophenotype, and adverse genetic features (i.e., BCR-ABL [t(9; 22)], ALL-1-AF4 [t(4; 11)], or E2APBX1 [t(l; 19) in pre-B ALL]); and < 5% leukemic blasts in bone marrow aspirate on day 15 of remission induction. Based on these criteria, approximately 50% of newly diagnosed ALL cases would be classified to have lower-risk leukemia, and their projected long-term event-free survival approaches 90%. This new classification schema is being applied in our current risk-adapted clinical protocol for ALL (Study XIIIB).