margetuximab

What is the most important information I should know about margetuximab?

What is margetuximab?

Margetuximab is used in combination with other cancer drugs to treat HER2-positive breast cancer that has spread to other parts of the body (metastatic).

Margetuximab is for use in people who have received at least two prior chemotherapy treatments for HER2-positive breast cancer.

Your doctor will test to make sure your cancer has an abnormal "HER2/neu" gene (a specific genetic marker).

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

What should I discuss with my healthcare provider before receiving margetuximab?

Tell your doctor if you have ever had heart problems.

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

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.

Margetuximab must be given slowly, and the infusion can take 30 minutes to 2 hours to complete. This medicine is sometimes given right after you've received other chemotherapy medication.

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?

What happens if I overdose?

Since this medicine 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.

What are the possible side effects of margetuximab?

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

• new or worsening cough;
• blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;
• heart problems --pounding heartbeats, dizziness, swelling in your face or lower legs, rapid weight gain (more than 5 pounds in 1 day), feeling short of breath;
• 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, or tingling in your arms or legs;
• muscle or joint pain;
• hand-foot syndrome; or
• side effects during the injection.

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.

What other drugs will affect margetuximab?

This medicine 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.

Where can I get more information?

Your doctor pharmacist can provide more information about margetuximab.