Gemtuzumab Ozogamicin

What it is and how it works

Mechanism of Action Gemtuzumab ozogamicin is a CD33-directed antibody-drug conjugate (ADC). The antibody portion (hP67.6) recognizes human CD33 antigen. The small molecule, N-acetyl gamma calicheamicin, is a cytotoxic agent that is covalently attached to the antibody via a linker. Nonclinical data suggest that the anticancer activity of gemtuzumab ozogamicin is due to the binding of the ADC to CD33-expressing tumor cells, followed by internalization of the ADC-CD33 complex, and the intracellular release of N-acetyl gamma calicheamicin dimethyl hydrazide via hydrolytic cleavage of the linker.

Mechanism class: CD33-directed Antibody Interactions

Indications

is a CD33-directed antibody and cytotoxic drug conjugate indicated for: • treatment of newly-diagnosed CD33-positive acute myeloid leukemia (AML) in adults and pediatric patients 1 month and older . • treatment of relapsed or refractory CD33-positive AML in adults and pediatric patients 2 years and older . Newly-Diagnosed CD33-positive Acute Myeloid Leukemia (AML) MYLOTARG is indicated for the treatment of newly-diagnosed CD33-positive acute myeloid leukemia in adults and pediatric patients 1 month and older. Relapsed or Refractory CD33-positive AML MYLOTARG is indicated for the treatment of relapsed or refractory CD33-positive acute myeloid leukemia in adults and pediatric patients 2 years and older.

Dosage and administration (summary)

• Newly-diagnosed, de novo AML (combination regimen) Adults : - Induction: 3 mg/m 2 (up to one 4.5 mg vial) on Days 1, 4, and 7 in combination with daunorubicin and cytarabine . - Consolidation: 3 mg/m 2 on Day 1 (up to one 4.5 mg vial) in combination with daunorubicin and cytarabine . Pediatric patients 1 month and older : - 3 mg/m 2 for patients with body surface area (BSA) 0.6 m 2 or greater . - 0.1 mg/kg for patients with BSA less than 0.6 m 2 . - See Full Prescribing Information for complete dosing information . • Newly-diagnosed AML (single-agent regimen): Adults : - Induction: 6 mg/m 2 (not limited to one 4.5 mg vial) on Day 1 and 3 mg/m 2 (not limited to one 4.5 mg vial) on Day 8 .

Contraindications

is contraindicated in patients with a history of hypersensitivity to the active substance in MYLOTARG or any of its components or to any of the excipients. Reactions have included anaphylaxis . Hypersensitivity to MYLOTARG or any of its components .

Warnings and precautions

• Infusion-related reactions (including anaphylaxis): Premedicate with a corticosteroid, acetaminophen, and diphenhydramine. Monitor patients during and for at least 1 hour after the end of the infusion. Interrupt the infusion, administer steroids or antihistamines, or permanently discontinue treatment as necessary ( 2.1 , 5.2 , 6 ). • Hemorrhage: Severe, including fatal, hemorrhage may occur when MYLOTARG is used at recommended doses. Monitor platelet counts frequently ( 5.3 , 6.1 ). • Embryo-fetal toxicity: Can cause fetal harm.

Pregnancy

Pregnancy Risk Summary Based on its mechanism of action and findings from animal studies , MYLOTARG can cause embryo-fetal harm when administered to a pregnant woman. There are no available data on MYLOTARG use in pregnant women to evaluate for a drug-associated risk.

Storage and supply

Refrigerate (2°C to 8°C; 36°F to 46°F) MYLOTARG vials and store in the original carton to protect from light. DO NOT FREEZE. MYLOTARG is a cytotoxic drug. Follow applicable special handling and disposal procedures. 1

Source: Gemtuzumab Ozogamicin (Mylotarg) — US FDA prescribing information, 2025-12-19, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.