Please check your internet connection and try again.
# Mylotarg (Gemtuzumab Ozogamicin)
## Overview
Gemtuzumab ozogamicin is a CD33-directed antibody-drug conjugate (ADC). It consists of a monoclonal antibody (anti-CD33) linked to the cytotoxic agent calicheamicin, which causes DNA double-strand breaks leading to cell apoptosis.
## Primary Indications
* Newly diagnosed CD33-positive acute myeloid leukemia (AML) in adults and pediatric patients aged 1 month and older.
* Relapsed or refractory CD33-positive AML in adults and pediatric patients aged 2 years and older.
## 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 (Monotherapy):** 9 mg/m² as a single dose. Subsequent dose (if needed) is 9 mg/m² at least 14 days later, or 3 mg/m² on days 1, 4, and 7.
## Pediatric Dosing
* **Patients $\geq$ 1 month:**
* **Newly Diagnosed:** 3 mg/m² (up to a max of 4.5 mg) on days 1, 4, and 7 of the induction cycle. For patients with a body surface area (BSA) < 0.6 m², the dose is 0.1 mg/kg.
* **Relapsed/Refractory:** 3 mg/m² (BSA $\geq$ 0.6 m²) or 0.1 mg/kg (BSA < 0.6 m²) on days 1, 4, and 7.
## Dose Adjustments
* **Hepatic Impairment:** Avoid in patients with severe hepatic impairment (total bilirubin > 3x ULN and AST/ALT > 2.5x ULN). Use with caution in patients with baseline bilirubin > 2x ULN.
* **Renal Impairment:** No specific adjustment required for mild to moderate impairment.
## Contraindications
* Known hypersensitivity to gemtuzumab ozogamicin.
## Adverse Effects
* **Hepatotoxicity:** Including Veno-Occlusive Disease (VOD)/Sinusoidal Obstruction Syndrome (SOS).
* **Infusion-Related Reactions:** Chills, fever, tachycardia, hypotension.
* **Myelosuppression:** Severe neutropenia, thrombocytopenia, and anemia.
* **Infections:** Risk of opportunistic infections due to immunosuppression.
* **Hemorrhage:** Risk of intracranial or GI bleeding.
## Key Drug Interactions
* **QT Prolonging Agents:** Risk of additive QT interval prolongation.
* **Strong CYP3A4 inhibitors/inducers:** Monitor for altered safety/efficacy (though the cytotoxic payload is primarily metabolic-independent, the conjugate metabolism may be affected).
## Monitoring
* **Liver Function:** Baseline and prior to each dose; monitor for signs of VOD (weight gain, jaundice, hepatomegaly).
* **CBC:** Monitor blood counts frequently throughout therapy.
* **Cardiac:** Monitor for signs of infusion-related reactions; ECG/electrolytes if on concomitant QT-prolonging medications.
## Clinical Pearls
* **VOD Risk:** The risk of VOD is significantly increased in patients undergoing hematopoietic stem cell transplantation (HSCT) post-therapy. Delay HSCT for at least 2 weeks after the last dose.
* **Premedication:** Administer corticosteroids, antihistamines, and antipyretics 1 hour prior to infusion to mitigate reaction symptoms.
* **Administration:** Infuse over 2 hours; protect from light during preparation and administration.
***
**Educational Disclaimer:** This information is for educational purposes only. Always verify dosages, contraindications, and drug interactions against the most current institutional protocols and the official FDA-approved prescribing information (package insert) before prescribing or administering medication.
