The Food and Drug Administration (FDA) extended the indication of gemtuzumab ozogamicin for newly-diagnosed CD33-positive acute myeloid leukaemia (AML) to include paediatric patients 1 month and older.

Efficacy and safety in the paediatric population were supported by data from AAML0531 (NCT00372593), a multi-centre randomised study of 1,063 patients with newly-diagnosed AML ages 0 to 29 years.

Patients were randomised to 5-cycle chemotherapy alone or with gemtuzumab ozogamicin (3 mg/m2) administered once on day 6 in Induction 1 and once on day 7 in Intensification 2.

The main efficacy outcome measure was event-free survival (EFS) measured from the date of trial entry until induction failure, relapse, or death by any cause.

The EFS hazard ratio was 0.84 (95% CI: 0.71-0.99).

The estimated percentage of patients free of induction failure, relapse, or death at five years was 48% (95% CI: 43%-52%) in the gemtuzumab ozogamicin chemotherapy arm versus 40% (95% CI: 36%‑45%) in the chemotherapy alone arm.

No difference between treatment arms in overall survival was demonstrated.

The most common grade 3 and higher adverse reactions that occurred during Induction 1 and Intensification 2 in ≥ 5% of patients who received gemtuzumab ozogamicin were infection, febrile neutropenia, decreased appetite, hyperglycaemia, mucositis, hypoxia, haemorrhage, increased transaminase, diarrhoea, nausea, and hypotension.

Source: The Food and Drug Administration