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# Mylotarg (gemtuzumab ozogamicin)
## Overview
Mylotarg is an antibody-drug conjugate (ADC) that targets CD33-expressing cells, used in the treatment of acute myeloid leukemia (AML).
## Primary Indications
* Treatment of newly diagnosed adult patients with acute myeloid leukemia (AML) who are >= 75 years of age or unable to receive intensive induction chemotherapy.
* Treatment of relapsed or refractory (R/R) adult patients with AML.
## Adult Dosing
**Newly Diagnosed AML (>= 75 years or ineligible for intensive induction chemotherapy):**
* Day 1: 3 mg/kg intravenously (IV)
* Day 4: 3 mg/kg IV
* Day 7: 2 mg/kg IV
**Relapsed or Refractory AML:**
* Cycle 1: 6 mg/kg IV on Day 1
* If tolerated, Day 2: 3 mg/kg IV
* Cycle 2 (if tolerated): 3 mg/kg IV on Day 1, 4, and 7.
* Subsequent cycles (if tolerated): 3 mg/kg IV every 2 to 4 weeks.
**Maximum dose per administration:** 6 mg/kg for Cycle 1 of R/R AML.
## Pediatric Dosing
Safety and efficacy have not been established in pediatric patients.
## Dose Adjustments
* **Hepatotoxicity:** Dose interruption or discontinuation may be required based on the severity of liver enzyme elevations and/or bilirubin levels. Consult prescribing information for specific criteria.
* **Thrombocytopenia:** Dose interruption or discontinuation may be required based on platelet count and bleeding severity. Consult prescribing information for specific criteria.
* **Infusion Reactions:** Slowing or interrupting the infusion may be necessary.
## Contraindications
* None listed in standard prescribing information.
## Adverse Effects
* **Hepatotoxicity:** Including sinusoidal obstruction syndrome (SOS)/veno-occlusive disease (VOD), hyperbilirubinemia, and transaminase elevations. This is a potentially life-threatening adverse event.
* **Myelosuppression:** Including neutropenia, thrombocytopenia, and anemia.
* **Infusion-related reactions:** Fever, chills, rash, dyspnea.
* Gastrointestinal effects: Nausea, vomiting, diarrhea, stomatitis.
* Fatigue, headache, pyrexia.
## Key Drug Interactions
* **Potent CYP3A4 inhibitors/inducers:** Gemtuzumab ozogamicin is metabolized by CYP3A4. Coadministration with potent CYP3A4 inhibitors or inducers may affect plasma concentrations of the active metabolite. Closely monitor for adverse effects or lack of efficacy.
## Monitoring
* **Liver Function Tests (LFTs):** Monitor ALT, AST, alkaline phosphatase, and bilirubin before and regularly during treatment, especially during the first cycle.
* **Complete Blood Count (CBC) with differential and platelet count:** Monitor frequently during treatment for myelosuppression.
* **Signs and symptoms of infusion reactions and hepatotoxicity.**
* **Signs of bleeding.**
## Clinical Pearls
* Hepatotoxicity, particularly SOS/VOD, is a serious and potentially fatal adverse event. Patients with known hepatic impairment may be at increased risk.
* Administer prophylactic antipyretics, antihistamines, and antiemetics prior to infusion to prevent infusion-related reactions.
* Monitor patients closely for signs and symptoms of bleeding and infection due to myelosuppression.
* The 2 mg/kg dose in Cycle 1 of R/R AML is only given if the patient tolerates the initial 6 mg/kg dose.
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*Disclaimer: This information is intended for healthcare professionals. Always consult the most current prescribing information and institutional protocols for complete details. Clinical decisions should be individualized based on patient-specific factors.*
