FDA extends approval for gemtuzumab ozogamicin in newly diagnosed CD33-positive AML

On June 16, 2020, the U.S. Food and Drug Administration (FDA) extended the indication of gemtuzumab ozogamicin (GO) for newly diagnosed CD33-positive acute myeloid leukemia (AML) to include pediatric patients ≥ 1 month of age. This approval was based on data from the AAML0531 trial (NCT00372593).¹

Study design^1,2

• Phase III, multicenter, randomized study of 1,063 patients with newly diagnosed AML who were between the ages of 0 and 29 years
• Aimed to compare the efficacy of GO in combination with chemotherapy with that of chemotherapy alone
• Patients were randomized to 5-cycle chemotherapy alone or with GO administered at 3 mg/m² once on Day 6 in the induction 1 stage and once on Day 7 of the intensification 2 stage
• Primary endpoint: Event-free survival (EFS), measured from the date of trial entry until induction failure, relapse, or death by any cause
• The study started in August 2006 and completed in August 2013

Results¹

• EFS hazard ratio was 0.84 (95% CI, 0.71–0.99)
• Estimated percentage of patients free of induction failure, relapse, or death at 5 years was 48% (95% CI, 43–52) in the chemotherapy plus GO arm vs 40% (95% CI, 36–45) in the chemotherapy alone arm
• No demonstrable difference in overall survival between treatment arms
• The most common ≥ Grade 3 adverse reactions occurring in at least 5% of patients treated with GO included infection, febrile neutropenia, decreased appetite, hyperglycemia, mucositis, hypoxia, hemorrhage, increased transaminase, diarrhea, nausea, and hypotension

GO was previously approved by the FDA for the treatment of adult patients with newly diagnosed CD33-positive AML. Ongoing trials AML18 and AML19 are investigating how GO should be applied in AML and whether a fractionated dosing schedule can provide benefit over a single dose.