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Generic Name: margetuximab (MAR je TUX i mab)
Brand Name: Margenza
Dosage Forms: intravenous solution (25 mg/mL)

Medically reviewed by on Jan 11, 2021. Written by Cerner Multum.

What is margetuximab?

Margetuximab is used in combination with other cancer drugs to treat breast cancer that has spread to other parts of the body (metastatic).

Margetuximab is given after at least two other cancer treatments did not work or have stopped working.

Margetuximab is used only if your cancer has a specific genetic marker (an abnormal "HER2/neu" gene). Your doctor will test you for this gene.

Margetuximab may also be used for purposes not listed in this medication guide.


Margetuximab may cause heart problems. Call your doctor at once if you have symptoms such as: fast or pounding heartbeats, cough, shortness of breath, swelling, or rapid weight gain.

Before taking this medicine

Tell your doctor if you have ever had heart problems.

You may need to have a negative pregnancy test before starting this treatment.

Margetuximab may harm an unborn baby. Use effective birth control to prevent pregnancy, and tell your doctor if you become pregnant. Keep using birth control for at least 4 months after your last dose.

It may not be safe to breastfeed while using margetuximab, and for at least 4 months after your last dose. Ask your doctor about any risk.

How is margetuximab given?

Margetuximab is given as an infusion into a vein. A healthcare provider will give you this injection.

Margetuximab is usually given once every 3 weeks. Follow your doctor's dosing instructions very carefully.

This medicine must be given slowly, and the infusion can take 30 minutes to 2 hours to complete.

Your heart function may need to be checked using an electrocardiograph (sometimes called an EKG) or ultrasound. Your cancer treatments may be delayed or permanently discontinued based on the results.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your margetuximab injection.

What happens if I overdose?

Since margetuximab is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving margetuximab?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Margetuximab side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Some side effects may occur during the injection. Tell your caregiver if you feel dizzy, tired, nauseated, light-headed, itchy, feverish, chilled, or have a headache, joint pain, cough fast heartbeats, trouble breathing, or swelling in your face.

Call your doctor at once if you have:

  • blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;

  • heart problems--fast or pounding heartbeats, cough, feeling light-headed or short of breath, swelling in your face or lower legs, rapid weight gain (more than 5 pounds in 1 day);

  • hand-foot syndrome--pain, blisters, bleeding, or severe rash on the palms of your hands or the soles of your feet; or

  • low white blood cell counts--fever, mouth sores, skin sores, sore throat, cough, trouble breathing.

Common side effects may include:

  • feeling weak or tired;

  • stomach pain, nausea, vomiting, loss of appetite;

  • diarrhea, constipation;

  • fever;

  • hair loss;

  • headache;

  • cough, trouble breathing;

  • pain, numbness, tingling, or burning pain in your arms or legs;

  • hand-foot syndrome; or

  • muscle or joint pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Margetuximab dosing information

Usual Adult Dose for Breast Cancer:

15 mg/kg IV every 3 weeks

-Infuse initial dose over 120 minutes and subsequent doses over 30 minutes.
-This drug may be administered immediately after the completion of chemotherapy.
-Continue treatment until disease progression or unacceptable toxicity.
-All therapeutic proteins, including this drug, have the potential to produce an immune response.

Use: 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 was for metastatic disease

What other drugs will affect margetuximab?

margetuximab can have long-lasting effects on your body. For at least 4 months after your last dose of margetuximab, you should not be treated with certain other cancer drugs. Tell each of your doctors about your treatment with margetuximab.

Other drugs may affect margetuximab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

More about margetuximab

Consumer resources

Other brands

Professional resources

Related treatment guides

Further information

  • Your doctor pharmacist can provide more information about margetuximab.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.