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# Mylotarg (gemtuzumab ozogamicin)
## Overview
Mylotarg is an antibody-drug conjugate that targets CD33, a protein found on most leukemia cells, and delivers a cytotoxic agent (calicheamicin) to kill these cells.
## Primary Indications
Treatment of adult patients with newly diagnosed acute myeloid leukemia (AML) who are younger than 60 years and are candidates for intensive induction chemotherapy.
Treatment of adult patients with relapsed or refractory AML.
## Adult Dosing
**Newly Diagnosed AML (as induction and consolidation):**
* **Induction:** 6 mg/m² on days 1, 4, and 7. If remission is achieved, consider consolidation.
* **Consolidation:** 3.5 mg/m² on days 1, 4, and 7. A maximum of 4 cycles (one induction and up to three consolidation cycles) may be administered.
**Relapsed or Refractory AML:**
* 6 mg/m² on day 1.
* If remission is achieved, a second dose of 3.5 mg/m² may be administered on day 4.
## Pediatric Dosing
Safety and effectiveness have not been established in pediatric patients.
## Dose Adjustments
* **Hepatotoxicity:** If ALT > 5 times ULN or total bilirubin > 2 times ULN, withhold Mylotarg until toxicity resolves. If AST > 5 times ULN, withhold. Consult prescribing information for specific dose reduction guidelines based on grade of hepatotoxicity.
* **Thrombocytopenia:** If platelet count < 50,000/µL, withhold Mylotarg. Do not resume until platelets recover.
* **Mucositis/Stomatitis:** If Grade 3 or 4, withhold. Resume at a reduced dose (3.5 mg/m²) once toxicity resolves to Grade 1 or less.
## Contraindications
* None listed.
## Adverse Effects
* **Hepatotoxicity:** Including veno-occlusive liver disease (VOD)/sinusoidal obstruction syndrome (SOS), elevated transaminases, and hyperbilirubinemia. This is a significant concern and can be fatal.
* **Myelosuppression:** Including neutropenia, thrombocytopenia, and anemia.
* **Bleeding events:** Including gastrointestinal hemorrhage and intracranial hemorrhage.
* **Infusion-related reactions:** Fever, rash, dyspnea.
* **Nausea, vomiting, diarrhea, mucositis.**
## Key Drug Interactions
* **Strong CYP3A4 inhibitors:** May increase exposure to calicheamicin, potentially increasing toxicity. Use with caution.
* **Hepatotoxic agents:** Concomitant use may increase the risk or severity of hepatotoxicity.
## Monitoring
* **Liver function tests:** Including ALT, AST, and bilirubin, at baseline and regularly during treatment.
* **Complete blood counts (CBC) with differential and platelet count:** At baseline and regularly during treatment.
* **Signs and symptoms of VOD/SOS:** Monitor for fluid retention, elevated liver enzymes, jaundice, and right upper quadrant pain.
* **Signs and symptoms of infusion-related reactions and bleeding events.**
## Clinical Pearls
* **VOD/SOS is a life-threatening complication.** Early recognition and management are critical. Pre-treatment screening for VOD risk factors and close monitoring are essential.
* **Infusion reactions can occur.** Administer premedications as appropriate and monitor closely during infusion.
* **Dosing is weight-based (mg/m²).** Ensure accurate calculation.
* **Consult the full prescribing information for detailed dose modification guidelines for specific toxicities.**
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*This information is intended for clinical pharmacists and healthcare professionals. It is essential to consult the most current prescribing information for Mylotarg (gemtuzumab ozogamicin) and relevant institutional protocols before initiating therapy.*
