# COG AAML0531

Source: https://onco.cc/trials/aaml0531/  
OnCo record `aaml0531` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Adding the antibody-drug conjugate gemtuzumab ozogamicin to chemotherapy lowered the chance of relapse in children with acute myeloid leukaemia. Years after the drug had been withdrawn from the US market, this trial helped bring it back for children.

## Summary

Randomised phase 3 (Gamis et al., JCO 2014), 1,022 evaluable patients. Gemtuzumab ozogamicin (GO, 3 mg/m2) given once in induction course 1 and once in intensification course 2 improved 3-year event-free survival (53.1% versus 46.9%; HR 0.83; 95% CI 0.70 to 0.99) through a reduction in relapse risk, with a non-significant trend in overall survival and slightly higher post-remission treatment-related mortality. Benefit was later shown to track with CD33 expression and CD33 splicing genotype, an early example of a pharmacogenomic biomarker in paediatric oncology. GO had been withdrawn in the US in 2010 after the adult SWOG S0106 trial; AAML0531 together with the adult ALFA-0701 trial supported the 2017 FDA re-approval, which included children. Successor COG trials (AAML1031, AAML1831) build on this backbone with FLT3 inhibitors and CPX-351.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-10
- Tags: nci-coverage; paediatric; haematologic
- Registry id: NCT00372593
- Phase: 3
- Setting: Newly diagnosed AML, age 0-29: standard five-course chemotherapy with or without two doses of gemtuzumab ozogamicin
- Sponsor: Children's Oncology Group
- Enrolled: 1070
- Result: 3-year EFS 53.1% vs 46.9%, HR 0.83; relapse risk reduced.
- Outcomes: 3-year event-free survival: Chemotherapy + gemtuzumab ozogamicin 53.1% vs Chemotherapy 46.9%, HR 0.83
- Replication: Adult ALFA-0701 (fractionated GO) and the MRC AML15/16 meta-analysis showed the same relapse reduction; the CD33 splicing biomarker was confirmed in AAML0531 and AAML1031 correlative studies.

## Sources

- ClinicalTrials.gov NCT00372593: https://clinicaltrials.gov/study/NCT00372593
- Gamis et al., JCO 2014: https://doi.org/10.1200/JCO.2014.55.3628

## Connected records

- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [Acute myeloid leukaemia in children](https://onco.cc/cancers/aml-paediatric/)
- technologies: [Antibody-drug conjugate (ADC)](https://onco.cc/technologies/adc/)
- targets: [CD33](https://onco.cc/targets/cd33/)
- drugs: [Cytarabine + anthracycline ('7+3')](https://onco.cc/drugs/cytarabine-7-3/), [Gemtuzumab ozogamicin](https://onco.cc/drugs/gemtuzumab-ozogamicin/)
- companies: [Children's Oncology Group (COG)](https://onco.cc/companies/childrens-oncology-group/)
- trials: [ALFA-0701](https://onco.cc/trials/alfa-0701/)
- key papers: [AAML0531: gemtuzumab ozogamicin added to chemotherapy for children and adolescents with acute myeloid leukaemia](https://onco.cc/key-papers/paper-aaml0531-gemtuzumab-gamis-jco-2014/)
- roadmaps: [Paediatric oncology roadmap: cooperative-group cures → engineered immunity → drugs developed for children first](https://onco.cc/roadmaps/paediatric-oncology-roadmap/)

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