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# Mylod (Mylotarg / Gemtuzumab Ozogamicin)
## Overview
Gemtuzumab ozogamicin is a CD33-directed antibody-drug conjugate (ADC) consisting of a humanized anti-CD33 monoclonal antibody linked to the cytotoxic agent calicheamicin. It is designed to target CD33-expressing leukemia cells to induce DNA double-strand breaks and apoptosis.
## Primary Indications
* Newly diagnosed CD33-positive acute myeloid leukemia (AML) in adults and pediatric patients (aged ≥1 month).
* Relapsed or refractory CD33-positive AML in adults and pediatric patients (aged ≥2 years).
## Adult Dosing
* **Newly Diagnosed AML (Combination Therapy):** 3 mg/m² (up to a maximum dose of 4.5 mg) on Days 1, 4, and 7 of the induction cycle.
* **Relapsed/Refractory AML:** 3 mg/m² (up to a maximum dose of 4.5 mg) on Days 1, 4, and 7.
* *Note:* Dose is based on Body Surface Area (BSA). Always verify strict adherence to institutional protocols regarding BSA-based rounding for this agent.
## Pediatric Dosing
* **Patients ≥1 month (Newly Diagnosed):** 3 mg/m² (up to a maximum of 4.5 mg) on Days 1, 4, and 7. For patients with a BSA < 0.6 m², the dose is 0.1 mg/kg on Days 1, 4, and 7.
* **Patients ≥2 years (Relapsed/Refractory):** 3 mg/m² (up to a maximum of 4.5 mg) on Days 1, 4, and 7.
## Dose Adjustments
* **Hepatic Impairment:** No formal adjustment for mild impairment. Avoid in patients with moderate to severe hepatic impairment or direct bilirubin >2x ULN.
* **Renal Impairment:** No formal adjustment required for doses up to 3 mg/m².
* **Hematologic Toxicity:** Dose modifications are typically not performed for cytopenias during the induction phase as intended myelosuppression is expected; however, recovery should be monitored closely before proceeding to consolidation.
## Contraindications
* Known hypersensitivity to gemtuzumab ozogamicin or any component of the formulation.
* Patients with active, uncontrolled infections.
## Adverse Effects
* **Hepatotoxicity:** Risk of severe and potentially fatal Veno-Occlusive Disease / Sinusoidal Obstruction Syndrome (VOD/SOS).
* **Infusion-Related Reactions:** Fever, chills, hypotension, and dyspnea (premedication with corticosteroids, antihistamines, and acetaminophen is mandatory).
* **Hematologic:** Prolonged neutropenia, thrombocytopenia, and anemia.
* **Gastrointestinal:** Stomatitis, nausea, and vomiting.
## Key Drug Interactions
* **Hepatotoxic Agents:** Risk of additive liver toxicity; avoid concomitant use with other known hepatotoxins when possible.
* **Live Vaccines:** Avoid live virus vaccines during therapy; immune response may be impaired.
* **Strong CYP3A4 Inhibitors/Inducers:** While calicheamicin is a substrate, clinical dose adjustments are not standardized; monitor for increased toxicity or decreased efficacy.
## Monitoring
* **Hepatic Function:** Baseline and regular monitoring of bilirubin, AST/ALT, and alkaline phosphatase. Monitor for signs of VOD/SOS (weight gain, hepatomegaly, ascites, jaundice).
* **CBC:** Frequent monitoring of blood counts for evidence of myelosuppression and recovery.
* **Infection:** Monitor for signs of opportunistic infections during periods of prolonged neutropenia.
## Clinical Pearls
* **VOD/SOS Awareness:** The risk of VOD/SOS is significantly increased in patients undergoing hematopoietic stem cell transplantation (HSCT) post-gemtuzumab. Maintain a minimum washout period between gemtuzumab and subsequent HSCT per protocol.
* **Premedication:** Always administer premedication at least 1 hour prior to infusion to attenuate hypersensitivity.
* **Stability:** The drug must be protected from light during reconstitution and infusion. Use only 0.9% Sodium Chloride for administration.
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**Educational Disclaimer:** This information is for educational purposes and does not substitute for clinical judgment. Always verify current prescribing information in the official FDA-approved package insert or local institutional guidelines before administration.
