Detailed instructions for use of Margetuximab/Meganex

1. Generic names: Margetuximab, Margetuximab

Product name: MARGENZA, MARGENZA

Other names: Magituximab Injection, Magituximab, Magituximab Injection

2. Indications:

Margetuximab is indicated in combination with chemotherapy for the treatment of adult patients with metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 regimens, at least one of which is used to treat metastatic disease.

3. Usage and dosage:

1. Recommended dose and schedule: The recommended dose of margituximab is 15 mg/kg, intravenously infused every 3 weeks (21-day cycle) until disease progression or unacceptable toxicity occurs. Administer margituximab as an initial intravenous infusion of 15 mg/kg over 120 minutes, followed by all subsequent doses over at least 30 minutes every 3 weeks. On days when margetuximab and chemotherapy are used simultaneously, margetuximab can be given immediately after chemotherapy is completed.

2. Dose adjustment: If the patient misses a dose of margetuximab, please take the scheduled dose as soon as possible. Adjust the dosing schedule to maintain a 3-week interval between doses.

4. Adverse reactions:

In clinical studies of margetuximab, common adverse reactions may include fatigue/asthenia, nausea, diarrhea, and vomiting; there is also a boxed warning regarding left ventricular dysfunction and embryo-fetal toxicity.

5. Supply and storage:

Margetuximab injection is a clear to slightly opalescent, colorless to light yellow or light brown solution in a single-dose vial containing 250 mg/10 milliliters (25 milligrams per milliliter [mg/mL]). Store vials refrigerated in the original carton at 2°C to 8°C (36°F to 46°F) to protect from light until use.

6. Mechanism of action:

Margituximab binds to the extracellular domain of the human epidermal growth factor receptor2 protein (HER2) . After binding to HER2-expressing tumor cells, margetuximab inhibits tumor cell proliferation, reduces the shedding of the extracellular domain of HER2, and mediates antibody-dependent cellular cytotoxicity (ADCC). In vitro, the modified Fc region of margetuximab increased binding to the activating Fc receptor FCGR3A (CD16A) and decreased binding to the inhibitory Fc receptor FCGR2B (CD32B). These changes resulted in greater ADCC and NK cell activation in vitro.

7. Listing situation:

Original research version:

China: Approved on 2023-08-29 (trade name: McGanle);

United States: Approved on 2020-12-16 (trade name: MARGENZA).

8. Special groups:

1. Women: According to animal research results and mechanism of action, magituximab used by pregnant women can cause harm to the fetus. Verify pregnancy status in females of reproductive potential before initiating an infusion of margetuximab. Inform pregnant women and females of reproductive potential that exposure to margetuximab during pregnancy or within 4 months before conception can cause fetal harm. Advise females of reproductive potential to use an effective method of contraception during treatment and for 4 months after the last dose.

Reference materials:https://www.margenza.com/