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# Mylod (Mylotarg / Gemtuzumab Ozogamicin) ## Overview Gemtuzumab ozogamicin is a CD33-directed antibody-drug conjugate (ADC). It consists of a monoclonal antibody linked to calicheamicin, a potent cytotoxic agent that induces double-strand DNA breaks, leading to cell cycle arrest and apoptosis in CD33-positive cells. ## Primary Indications Treatment of newly diagnosed CD33-positive acute myeloid leukemia (AML) in adults and pediatric patients 1 month and older. Also indicated for relapsed or refractory CD33-positive AML. ## Adult Dosing * **Newly diagnosed AML (Combination):** 3 mg/m² (up to a maximum dose of 10 mg) on days 1, 4, and 7 of the induction cycle. * **Monotherapy:** 9 mg/m² as a single dose for relapsed/refractory cases, or 3 mg/m² on days 1, 4, and 7. * *Note: Max dose is 10 mg due to risk of hepatotoxicity.* ## Pediatric Dosing * **Ages 1 month and older:** Dosing is based on body surface area (BSA). * **Newly diagnosed (Combination):** 3 mg/m² (up to max of 10 mg) on days 1, 4, and 7. * *Consult institutional protocols for specific weight-based modifications in neonates or small infants.* ## Dose Adjustments * **Hepatic Impairment:** Avoid use in patients with severe hepatic impairment (Total bilirubin >2x ULN or AST/ALT >2.5x ULN). No dose adjustment required for mild impairment, but monitor closely. * **Renal Impairment:** No specific dose adjustment guidelines; use clinical judgment. ## Contraindications * Known hypersensitivity to gemtuzumab ozogamicin or any of its components. * Severe hepatic impairment. ## Adverse Effects * **Hepatotoxicity:** Including veno-occlusive disease (VOD) or sinusoidal obstruction syndrome (SOS). Increased risk with post-HSCT use. * **Myelosuppression:** Profound neutropenia, thrombocytopenia, and anemia. * **Infusion-Related Reactions:** Fever, chills, hypotension, and dyspnea. * **Infection:** High risk of opportunistic infections due to neutropenia. * **Tumor Lysis Syndrome:** Secondary to rapid cell death. ## Key Drug Interactions * **Hepatotoxic Agents:** Risk of VOD/SOS is additive; exercise caution with concomitant use of drugs known to cause liver injury. * **Strong CYP3A inhibitors/inducers:** May theoretically alter the pharmacokinetics of the calicheamicin moiety, though clinical impact is often secondary to the ADC mechanism. ## Monitoring * **Liver Function Tests (LFTs):** Baseline and prior to each dose; specifically monitor bilirubin, alkaline phosphatase, and transaminases for signs of VOD. * **CBC:** Monitor blood counts frequently for cytopenias. * **Infection Signs:** Monitor temperature and blood cultures if febrile neutropenia is suspected. * **Cardiac/Electrolyte:** Baseline and periodic ECGs and electrolytes (magnesium, potassium) to prevent/manage tumor lysis syndrome. ## Clinical Pearls * **Premedication:** Always administer corticosteroids, antihistamines, and antipyretics 1 hour prior to infusion to reduce infusion-related reactions. * **Handling:** This is a hazardous cytotoxic agent; follow strict USP <800> guidelines for handling, preparation, and disposal. * **VOD Risk:** The risk of VOD is significantly higher in patients undergoing hematopoietic stem cell transplantation (HSCT) post-therapy. Ensure a recovery interval (usually >60 days) between therapy and transplant if possible. *** **Educational Disclaimer:** This information is for educational purposes only. Drug information, protocols, and safety guidelines change frequently. Always verify current prescribing information, institutional guidelines, and the manufacturer’s package insert before administering any medication.