Mylod%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520at

# Mylotarg (gemtuzumab ozogamicin) ## Overview Mylotarg is a targeted immunotherapy, specifically an antibody-drug conjugate, that targets CD33-expressing cancer cells. It consists of a humanized anti-CD33 monoclonal antibody linked to the cytotoxic agent calicheamicin. ## Primary Indications * Treatment of newly diagnosed adult patients with acute myeloid leukemia (AML) who are ineligible for intensive induction chemotherapy. * Treatment of adult patients with relapsed or refractory AML. ## Adult Dosing **Newly Diagnosed, Chemotherapy-Ineligible AML:** * **First cycle:** 3 mg/kg on Day 1, Day 4, and Day 7. * **Second cycle (if achieving response):** 3 mg/kg on Day 1. * The second cycle should be administered approximately 14 to 21 days after the first cycle. **Relapsed or Refractory AML:** * **First cycle:** 6 mg/kg on Day 1. * **Second cycle (if achieving response):** 3 mg/kg on Day 1, approximately 14 to 21 days after the first cycle. * The maximum cumulative dose should not exceed 23.4 mg/kg. ## Pediatric Dosing Mylotarg is **not approved** for pediatric use. Limited data exists, and use would be considered off-label under specialist guidance. ## Dose Adjustments * **Hepatic Impairment:** If bilirubin > 1.5 times the upper limit of normal (ULN) or AST/ALT > 3 times ULN, the drug should be **held**. Once bilirubin is ≤ 1.5 ULN and AST/ALT are ≤ 3 ULN, Mylotarg can be administered at a reduced dose of 1.5 mg/kg. * **Renal Impairment:** No specific dose adjustments are recommended for mild to moderate renal impairment. Data is limited for severe renal impairment. ## Contraindications * None listed in standard prescribing information. ## Adverse Effects * **Hepatotoxicity:** Severe and potentially fatal hepatotoxicity, including hepatic veno-occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS), hyperbilirubinemia, and elevated AST/ALT. * **Myelosuppression:** Neutropenia, thrombocytopenia, anemia, and febrile neutropenia. * **Hemorrhage:** Including severe and fatal bleeding events. * **Infusion-related reactions:** Fever, chills, rash, dyspnea. * **Nausea, vomiting, diarrhea, mucositis, fatigue, peripheral neuropathy.** ## Key Drug Interactions * **Strong CYP3A4 Inhibitors/Inducers:** While gemtuzumab ozogamicin is an antibody-drug conjugate, caution is advised if co-administered with strong CYP3A4 inhibitors or inducers, as the cytotoxic payload (calicheamicin) might be subject to some metabolic pathways. However, clinically significant interactions are not well-established. ## Monitoring * **Liver Function Tests (LFTs):** Regularly monitor bilirubin, AST, ALT, and alkaline phosphatase, especially prior to each dose and as clinically indicated. Monitor closely for signs and symptoms of VOD/SOS. * **Complete Blood Counts (CBCs):** Monitor for myelosuppression, including neutrophil count, platelet count, and hemoglobin. * **Bleeding Events:** Monitor for signs and symptoms of bleeding. * **Infusion-related reactions:** Monitor vital signs and patient for signs of reaction during and after infusion. ## Clinical Pearls * **Hepatotoxicity is a significant risk.** Patients should be closely monitored for signs of VOD/SOS, including jaundice, ascites, hepatomegaly, and right upper quadrant pain. Dose modifications or discontinuation may be necessary. * **Consider prophylactic measures** for febrile neutropenia and bleeding based on patient's clinical status and local guidelines. * **Administer over 2 hours.** Monitor patients closely for infusion-related reactions. * **Restarting therapy after a response** in the newly diagnosed indication should occur approximately 14-21 days after the first cycle, provided ANC is ≥ 1.5 x 10^9/L, platelets are ≥ 50 x 10^9/L, and bilirubin is ≤ 1.5 ULN. *** **Disclaimer:** This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant guidelines before making treatment decisions. Drug information can change rapidly.