Children's Oncology Group AALL1731: blinatumomab added to chemotherapy for children with standard-risk B-cell ALL
Two courses of blinatumomab added to standard chemotherapy cut relapses in children with average- or higher-risk standard-risk leukaemia, raising three-year disease-free survival from 88% to 96%.
AALL1731 was a phase 3 Children's Oncology Group trial in children aged 1 to under 10 with newly diagnosed National Cancer Institute standard-risk B-cell ALL. Those with average- or high-risk features after induction (1440 patients) were randomised to standard chemotherapy or the same chemotherapy with two 28-day cycles of blinatumomab. The primary endpoint was disease-free survival. At the first interim analysis three-year DFS was 96.0% with blinatumomab versus 87.9% (hazard ratio 0.39), and randomisation was stopped early for efficacy. Sepsis and catheter-related infections were more frequent with blinatumomab, but there were few grade 3 or higher CRS or neurological events.
- 1440 children with NCI standard-risk B-ALL (average- or high-risk subgroups) randomised; chemotherapy with or without 2 cycles of blinatumomab.
- 3-year disease-free survival 96.0% vs 87.9%; hazard ratio 0.39.
- Benefit in both the average-risk and high-risk standard-risk subgroups.
- Randomisation halted early at interim analysis for efficacy.
- Higher rates of sepsis and catheter-related infections with blinatumomab; CRS and neurotoxicity rare and mostly low grade.
AALL1731 brings immunotherapy into the front-line treatment of the commonest childhood cancer, in the group of children where most relapses were occurring despite good initial risk. Blinatumomab was approved for this use in 2024 and paediatric protocols worldwide are being amended. Whether it can allow less chemotherapy, and its effect on very low-risk children, are the next questions.
- Early stopping at interim analysis may overestimate the effect size.
- Follow-up is short for a disease where late relapses occur; overall survival not yet different.
- Infection-related toxicity and central-line management are practical concerns in small children.
- Very favourable-risk children (not randomised) were not tested.