Mylotarg (gemtuzumab Ozogamicin)

# Mylotarg (gemtuzumab Ozogamicin) ## Overview Mylotarg is an antibody-drug conjugate targeting CD33-expressing myeloid cells. It consists of gemtuzumab, a humanized anti-CD33 monoclonal antibody, linked to the cytotoxic agent ozogamicin. ## Primary Indications Treatment of adults and pediatric patients 1 month and older with newly diagnosed or relapsed/refractory acute myeloid leukemia (AML) that is CD33-positive. ## Adult Dosing * **Newly Diagnosed CD33-Positive AML (in combination with chemotherapy):** * Day 1: 3 mg/kg IV infusion over 2 hours. * Day 4: 3 mg/kg IV infusion over 2 hours. * Day 7: 2 mg/kg IV infusion over 2 hours. * Maximum cumulative dose: 10 mg/kg. * **Relapsed/Refractory CD33-Positive AML:** * First cycle: 0.2 mg/kg IV infusion over 2 hours on days 1, 4, and 7. * Second cycle (if indicated): 0.2 mg/kg IV infusion over 2 hours on day 1. * Maximum dose per infusion: 0.2 mg/kg. * Maximum cumulative dose: 0.6 mg/kg. Dosing for combination therapy may depend on specific chemotherapy regimens and local protocols. ## Pediatric Dosing For CD33-positive AML in patients 1 month and older: * **Newly Diagnosed CD33-Positive AML (in combination with chemotherapy):** Dosing is based on body surface area (BSA) and depends on the specific chemotherapy regimen and local institutional protocols. Consult specific pediatric oncology guidelines. * **Relapsed/Refractory CD33-Positive AML:** 0.2 mg/kg IV infusion over 2 hours on days 1, 4, and 7 for the first cycle, and on day 1 for the second cycle. ## Dose Adjustments * **Hepatic Impairment:** Use with caution. If bilirubin > 2.5 times ULN or AST > 5 times ULN, consider withholding or discontinuing. * **Renal Impairment:** No specific dose adjustments are recommended, but use with caution. ## Contraindications None specifically listed for gemtuzumab ozogamicin itself, but contraindications related to combination chemotherapy agents will apply. ## Adverse Effects Common adverse effects include: * Hepatotoxicity (including VOD/SOS) * Thrombocytopenia * Febrile neutropenia * Anemia * Nausea, vomiting, diarrhea * Mucositis * Hypersensitivity reactions * Hemorrhage * Fatigue ## Key Drug Interactions No specific drug interactions identified. However, caution is advised when co-administering with other myelosuppressive agents due to the risk of additive myelosuppression. ## Monitoring * **Hepatotoxicity:** Monitor liver function tests (ALT, AST, bilirubin) closely, especially for VOD/SOS symptoms (e.g., weight gain, hepatomegaly, ascites, thrombocytopenia, elevated bilirubin). * **Hematologic Parameters:** Monitor complete blood counts (CBC) with differential and platelet counts. * **Infusion Reactions:** Monitor vital signs during and after infusion. * **Hemorrhage:** Monitor for signs of bleeding. ## Clinical Pearls * Risk of Veno-occlusive disease/Sinusoidal Obstruction Syndrome (VOD/SOS) is a serious concern, particularly in patients with prior stem cell transplant or liver dysfunction. Early recognition and management are crucial. * Administer prophylactic anti-infectives as clinically indicated. * Administer prescribed antiemetics and antidiarrheals. * Premedication with corticosteroids, antihistamines, and antipyretics may be considered to reduce infusion-related reactions. *** _**Disclaimer:** This information is intended for clinical pharmacy professionals and does not replace a thorough review of the full prescribing information and patient-specific factors. Always consult the most current FDA-approved labeling for Mylotarg (gemtuzumab ozogamicin) for complete and up-to-date prescribing information._