Please check your internet connection and try again.
# Mylotarg (gemtuzumab ozogamicin)
## Overview
Mylotarg is a CD33-directed antibody-drug conjugate (ADC). It delivers the cytotoxic agent calicheamicin to CD33-expressing leukemia cells. It requires careful handling as a hazardous antineoplastic agent.
## Primary Indications
* Newly diagnosed CD33-positive acute myeloid leukemia (AML) in adults and pediatric patients ≥1 month.
* Relapsed or refractory CD33-positive AML in adults and pediatric patients ≥2 years.
## Adult Dosing
* **Newly Diagnosed AML:** 3 mg/m² (up to a maximum dose of 4.5 mg) on days 1, 4, and 7 in combination with daunorubicin and cytarabine.
* **Relapsed/Refractory AML:** 3 mg/m² (up to a maximum dose of 4.5 mg) on days 1, 4, and 7 as a single agent.
## Pediatric Dosing
* **Newly Diagnosed AML:**
* BSA ≥0.6 m²: 3 mg/m² (max 4.5 mg) on days 1, 4, and 7.
* BSA <0.6 m²: 0.1 mg/kg on days 1, 4, and 7.
* **Relapsed/Refractory AML:**
* 3 mg/m² (max 4.5 mg) on days 1, 4, and 7.
## Dose Adjustments
* **Hepatic Impairment:** Avoid in patients with total bilirubin >2x ULN or AST/ALT >2.5x ULN.
* **VOD/SOS:** Permanently discontinue if veno-occlusive disease (sinusoidal obstruction syndrome) develops.
* **Infusion-Related Reactions:** If Grade 3 or higher occurs, discontinue permanently.
## Contraindications
* Known hypersensitivity to gemtuzumab ozogamicin or any component of the formulation.
## Adverse Effects
* **Hepatotoxicity:** Including veno-occlusive disease (VOD/SOS), particularly in patients undergoing hematopoietic stem cell transplant (HSCT).
* **Myelosuppression:** Severe neutropenia, thrombocytopenia, and anemia.
* **Infusion-Related Reactions:** Fever, chills, hypotension, and dyspnea.
* **Infections:** Significant risk of opportunistic infections.
* **QT Prolongation.**
## Key Drug Interactions
* **QT-Prolonging Agents:** Use with caution; monitor ECGs closely.
* **Strong CYP3A4 Inhibitors/Inducers:** Use caution, though limited clinical data exist on the impact of CYP3A4 modulation on the calicheamicin payload.
## Monitoring
* **Liver Function Tests:** Monitor bilirubin, GGT, ALP, ALT, and AST prior to every dose.
* **CBC:** Monitor blood counts frequently throughout therapy.
* **Physical Exam:** Monitor for signs of hepatotoxicity (hepatomegaly, rapid weight gain, ascites).
* **ECG:** Monitor for QT prolongation as clinically indicated.
## Clinical Pearls
* **VOD Risk:** The risk of VOD is significantly elevated in patients who undergo HSCT post-treatment or who have underlying hepatic impairment.
* **Pre-medication:** Administer corticosteroids, antihistamines, and antipyretics 1 hour prior to each dose to mitigate infusion-related reactions.
* **Handling:** Must be prepared under a laminar flow hood; do not shake; protect from light.
* **Administration:** Infuse over 2 hours via a dedicated line; do not perform as an IV push.
* **Note:** Always verify dosing against current institutional protocols as pediatric dosing or combination regimens may vary by center.
***
**Educational Disclaimer:** This information is for educational purposes only. Always consult the latest FDA-approved prescribing information, institutional guidelines, and clinical trial protocols before administering this medication.
