Treatment of higher risk acute lymphoblastic leukemia in young people (CCG-1961), long-term follow-up: a report from the Children’s Oncology Group

Children’s Cancer Group CCG-1882 improved outcome for 1–21-year old with high risk acute lymphoblastic leukemia and Induction Day 8 marrow blasts ≥25% (slow early responders, SER) with longer and stronger post induction intensification (PII). This CCG-1961 explored alternative PII strategies. We report 10-year follow-up for patients with rapid early response (RER) and for the first time details our experience for SER patients. A total of 2057 patients were enrolled, and 1299 RER patients were randomized to 1 of 4 PII regimens: standard vs. augmented intensity and standard vs. increased length. At the end of interim maintenance, 447 SER patients were randomized to idarubicin/cyclophosphamide or weekly doxorubicin in the delayed intensification phases. The 10-year EFS for RER were 79.4 ± 2.4% and 70.9 ± 2.6% (hazard ratio = 0.65, 95% CI 0.52–0.82, p