ACNS0333: high-dose chemotherapy and three-dimensional conformal radiation for atypical teratoid/rhabdoid tumour
The first trial designed for atypical teratoid/rhabdoid tumour, a brain cancer of infants, showed that intensive chemotherapy with stem cell rescue and focused radiotherapy cut the risk of relapse or death by more than half compared with how children had been treated before.
Overview
Children's Oncology Group trial ACNS0333: patients from birth to 22 years with atypical teratoid/rhabdoid tumour had surgery, two courses of multi-agent induction chemotherapy, three courses of high-dose chemotherapy with peripheral blood stem cell rescue, and involved-field radiotherapy timed by age and disease extent. SMARCB1 testing was mandatory. The primary analysis compared event-free survival in children under 36 months with a historical cooperative group cohort.
Of 65 evaluable patients, 54 were under 36 months; the regimen significantly reduced the hazard of an event (hazard rate 0.43). Four-year event-free and overall survival for the whole cohort were 37 and 43 percent; 91 percent of relapses occurred within two years and four patients died of treatment.
- Hazard rate for an event 0.43 (95% CI 0.28 to 0.66; p < 0.0005) against the historical cohort in children under 36 months.
- Four-year event-free survival 37 percent (95% CI 25 to 49) and overall survival 43 percent (31 to 55).
- Timing of radiotherapy did not affect survival; four treatment-related deaths.
ACNS0333 established the treatment backbone for atypical teratoid/rhabdoid tumour and the platform on which new agents are being tested.
- Non-randomised comparison with historical controls.
- Molecular subgroup and clinical features suggest prognostic differences that the trial was not powered to test.