On June 16, the U.S. Food and Drug Administration (FDA) extended the indication of gemtuzumab ozogamicin (Mylotarg) for newly diagnosed CD33-positive acute myeloid leukemia (AML) to include pediatric patients aged 1 month and older.
Efficacy and safety in the pediatric population were supported by data from AAML0531, a multicenter, randomized study of 1,063 patients with newly diagnosed AML aged 0 to 29 years. Patients were randomly assigned to receive five-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 measured from the date of trial entry until induction failure, relapse, or death by any cause. The event-free survival hazard ratio was 0.84 (95% confidence interval [CI] = 0.71–0.99). The estimated percentage of patients free of induction failure, relapse, or death at 5 years was 48% (95% CI = 43%–52%) in the gemtuzumab ozogamicin plus chemotherapy arm vs 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 adverse reactions that occurred during induction 1 and intensification 2 in ≥ 5% of patients who received gemtuzumab ozogamicin were infection, febrile neutropenia, decreased appetite, hyperglycemia, mucositis, hypoxia, hemorrhage, increased transaminase, diarrhea, nausea, and hypotension.