The Food and Drug Administration (FDA) has expanded the approval of Mylotarg (gemtuzumab ozogamicin; Pfizer) to include treatment of patients aged 1 month and older with newly-diagnosed CD33-positive acute myeloid leukemia (AML). Previously, Mylotarg was only approved in adults for this indication.
The approval was based on data from the multicenter phase 3 AAML0531 study that evaluated the efficacy and safety of gemtuzumab ozogamicin plus chemotherapy in 1063 patients aged 0 to 29 years with newly-diagnosed AML. Patients were randomized to receive either 5-cycle chemotherapy alone or in combination with gemtuzumab ozogamicin administered by intravenous (IV) infusion once on day 6 of the induction 1 cycle and once on day 7 in the intensification 2 cycle. The co-primary end points were event-free survival (EFS), measured from date of trial entry until induction failure, relapse, or death by any cause, and overall survival (OS).
Findings from the study showed an EFS hazard ratio of 0.84 (95% CI, 0.71-0.99). At 5 years, the percentage of patients free of induction failure, relapse, or death was 48% (95% CI, 43-52) for the gemtuzumab ozogamicin plus chemotherapy arm and 40% (95% CI, 36-45) for the chemotherapy alone arm. No difference in OS was observed between the treatment arms.
With regard to safety, the most common adverse reactions of grade ≥3 that occurred during the induction 1 cycle and the intensification 2 cycle were infection, febrile neutropenia, decreased appetite, hyperglycemia, mucositis, hypoxia, hemorrhage, increased transaminase, diarrhea, nausea, and hypotension. Mylotarg also carries a Boxed Warning for hepatotoxicity, including severe or fatal hepatic veno-occlusive disease, also known as sinusoidal obstruction syndrome.
Mylotarg is also indicated for the treatment of relapsed or refractory CD33-positive AML in patients aged ≥2 years.
The product is supplied in a carton containing one 4.5mg single-dose vial for reconstitution and dilution.
For more information visit pfizer.com.