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# Mylotarg (gemtuzumab ozogamicin)
## Overview
Mylotarg is an antibody-drug conjugate consisting of a humanized anti-CD33 monoclonal antibody linked to the cytotoxic agent calicheamicin. It targets CD33-expressing cells, primarily myeloid blasts in acute myeloid leukemia (AML).
## Primary Indications
* Treatment of newly diagnosed adult patients with acute myeloid leukemia (AML) in morphologic remission, with the intention of proceeding to hematopoietic stem cell transplantation.
* Treatment of adult patients with relapsed or refractory AML.
## Adult Dosing
**Newly Diagnosed AML (in morphologic remission, for HSCT):**
* A single IV infusion of 3 mg/kg on day 1 of the treatment cycle.
* **Note:** Dosing is typically part of a chemotherapy regimen and further doses are based on local protocols and physician discretion.
**Relapsed or Refractory AML:**
* **First Cycle:** 3 mg/kg IV infusion on day 1.
* **Second Cycle (if eligible):** 3 mg/kg IV infusion on day 1.
* **Note:** For patients who have not achieved remission or have not proceeded to transplant after the second cycle, further cycles are generally not recommended.
## Pediatric Dosing
* Mylotarg is not approved for use in pediatric patients. Data is limited.
## Dose Adjustments
* **Hepatotoxicity:** Dose interruption or discontinuation may be necessary. See "Monitoring" for specific transaminase thresholds.
* **Thrombocytopenia:** Monitor platelet counts closely. Dose reduction is not specified, but interruption may be considered.
* **Infusion Reactions:** Slowing or stopping the infusion may be necessary.
## Contraindications
* None specified in product labeling. However, caution is advised in patients with severe hepatic impairment.
## Adverse Effects
* **Common:** Thrombocytopenia, nausea, vomiting, stomatitis, constipation, headache, fever, rash, fatigue, infection, diarrhea, peripheral neuropathy, liver test abnormalities.
* **Serious:** Hepatotoxicity (including VOD/SOS), myelosuppression, infusion reactions, tumor lysis syndrome, embryofetal toxicity.
* **Hepatotoxicity (VOD/SOS):** Early signs include weight gain, ascites, splenomegaly, jaundice, and hepatomegaly. Risk is higher in patients with prior stem cell transplant, elevated baseline bilirubin, or concomitant sirolimus therapy.
## Key Drug Interactions
* **Sirolimus:** Concomitant use with sirolimus in patients who have undergone HSCT increases the risk of VOD/SOS. Avoid concomitant use.
* **Other myelosuppressive agents:** Increased risk of myelosuppression.
## Monitoring
* **Complete Blood Counts (CBC) with differential:** Prior to each dose and regularly thereafter. Monitor for myelosuppression.
* **Liver Function Tests (LFTs):** Including AST, ALT, bilirubin, and alkaline phosphatase. Monitor prior to each dose and regularly.
* If AST or ALT > 3x ULN, interrupt gemtuzumab ozogamicin.
* If AST or ALT > 5x ULN, interrupt gemtuzumab ozogamicin.
* If AST or ALT > 10x ULN, discontinue gemtuzumab ozogamicin.
* If total bilirubin > 2x ULN, interrupt gemtuzumab ozogamicin.
* If total bilirubin > 3x ULN, discontinue gemtuzumab ozogamicin.
* **Renal Function:** Monitor urinalysis and renal function tests.
* **Signs and symptoms of VOD/SOS and infusion reactions:** Monitor closely during and after infusion.
## Clinical Pearls
* Administer over 60-120 minutes.
* Premedicate with corticosteroids, antihistamines, and antipyretics to reduce infusion reactions.
* Consider the risk of VOD/SOS, especially in patients with prior HSCT and elevated bilirubin. Early recognition is crucial.
* Use effective contraception during and for at least 6 months after treatment due to embryofetal toxicity.
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**Disclaimer:** This information is intended for clinical decision-making support and does not replace comprehensive drug information resources or professional judgment. Always consult the official prescribing information and current clinical guidelines for the most up-to-date and complete details before prescribing or administering any medication.
