Last reviewed 2026-04-20 · How we verify

Mylotarg (Gemtuzumab Ozogamicin)

CD33-directed antibody-drug conjugate that delivers cytotoxic calicheamicin to tumor cells.

MYLOTARG is a CD33-directed antibody-drug conjugate indicated for newly-diagnosed and relapsed/refractory CD33-positive AML in adults and pediatric patients. The drug demonstrates potent cytotoxic activity through targeted delivery of calicheamicin to CD33-expressing leukemic cells, with favorable pharmacokinetics showing increased half-life and decreased clearance after repeated dosing. Key risks include hypersensitivity reactions including anaphylaxis, with no clinically significant drug interactions at therapeutic concentrations. The fractionated dosing regimen (9 mg/m² doses 14 days apart) represents an important therapeutic option for AML patients with CD33-positive disease.

At a glance

Mechanism of action

Gemtuzumab ozogamicin is a CD33-directed antibody-drug conjugate composed of the hP67.6 antibody covalently attached to N-acetyl gamma calicheamicin via a linker. The antibody portion recognizes and binds to CD33 antigen expressed on tumor cells, followed by internalization of the ADC-CD33 complex into the cell. Upon internalization, hydrolytic cleavage of the linker releases N-acetyl gamma calicheamicin dimethyl hydrazide intracellularly. The released cytotoxic agent activates and induces double-strand DNA breaks, leading to cell cycle arrest and apoptotic cell death of CD33-expressing tumor cells.

Approved indications

• Acute myeloid leukemia, disease

Common side effects

• Platelets
• Hemoglobin
• Neutrophils/granulocytes (ANC/AGC)
• Leukocytes (total WBC)
• Fatigue (asthenia, lethargy, malaise)
• Glucose, serum-high (hyperglycemia)
• Albumin, serum-low (hypoalbuminemia)
• Sodium, serum-low (hyponatremia)
• Nausea
• Febrile neutropenia
• Constipation
• Anorexia

Drug interactions

• CYP450 enzymes (CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5)
• CYP450 enzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5)
• CYP450 enzymes (CYP1A2, CYP2B6, CYP3A4)
• UGT enzymes (UGT1A1, UGT1A4, UGT1A6, UGT1A9, UGT2B7)
• Drug transporters (P-gp, BCRP, OAT1, OAT3, OCT2, OATP1B1, OATP1B3)

Key clinical trials

• Azacitidine and Gemtuzumab Ozogamicin in Treating Older Patients With Previously Untreated Acute Myeloid Leukemia (PHASE2)

Primary sources

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