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Fam-trastuzumab deruxtecan

Generic name: fam-trastuzumab deruxtecan [ FAM-tras-TOOZ-ue-mab-DER-ux-TEE-kan ]
Brand name: Enhertu
Dosage form: intravenous powder for injection (100 mg)
Drug class: HER2 inhibitors

Medically reviewed by on Jul 7, 2022. Written by Cerner Multum.

What is fam-trastuzumab deruxtecan?

Fam-trastuzumab deruxtecan is used in adults to treat HER2-positive breast cancer that has spread to other parts of the body (metastatic) or cannot be removed with surgery.

Fam-trastuzumab deruxtecan is also used in adults who have received an anti-HER2 breast cancer treatment before for metastatic diseases, or have breast cancer that has come back within 6 months of completing treatment for early stages breast cancer.

Fam-trastuzumab deruxtecan can also used in adults to treat a certain type of HER2-positive esophageal cancer.

Fam-trastuzumab deruxtecan is usually given after other cancer treatments did not work or have stopped working.

Fam-trastuzumab deruxtecan may also be used for purposes not listed in this medication guide.


Fam-trastuzumab deruxtecan can cause serious or life-threatening side effects on your heart or lungs. Call your doctor right away if you have a cough, tiredness, dizziness, chest tightness, wheezing, irregular heartbeats, new or worsening shortness of breath.

Fam-trastuzumab deruxtecan can weaken (suppress) your immune system, and you may get an infection or bleed more easily. Tell your doctor if you have unusual bruising or bleeding, or signs of infection (fever, chills, weakness, cold or flu symptoms, frequent or recurring illness).

Both men and women using fam-trastuzumab deruxtecan should use effective birth control to prevent pregnancy. Birth control should be continued for 7 months after the last dose of fam-trastuzumab deruxtecan in women and 4 months after in men.

Related/similar drugs

Enhertu, Trodelvy, Alecensa, Ibrance, Opdivo, Retevmo, Exkivity

Before taking this medicine

Tell your doctor if you have ever had:

  • heart problems;

  • breathing problems; or

  • an infection.

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

Fam-trastuzumab deruxtecan can harm an unborn baby if the mother or the father is using this medicine.

  • If you are a woman, do not use fam-trastuzumab deruxtecan if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 7 months after your last dose.

  • If you are a man, use effective birth control if your sex partner is able to get pregnant. Keep using birth control for at least 4 months after your last dose.

  • Tell your doctor right away if a pregnancy occurs while either the mother or the father is using fam-trastuzumab deruxtecan.

This medicine may affect fertility (ability to have children), in men.

Do not breastfeed while using this medicine, and for at least 7 months after your last dose.

How is fam-trastuzumab deruxtecan given?

Your doctor will perform blood tests to make sure you do not have conditions that would prevent you from safely using fam-trastuzumab deruxtecan.

Fam-trastuzumab deruxtecan is given as an infusion into a vein. A healthcare provider will give you this injection.

Fam-trastuzumab deruxtecan is usually given once every 3 weeks in a 21-day treatment cycle. Your doctor will determine how long to treat you with fam-trastuzumab deruxtecan.

You may be given medication to prevent nausea or vomiting while you are receiving fam-trastuzumab deruxtecan.

You will need frequent medical tests.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your fam-trastuzumab deruxtecan injection.

What happens if I overdose?

Since fam-trastuzumab deruxtecan is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving fam-trastuzumab deruxtecan?

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

Fam-trastuzumab deruxtecan 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.

Fam-trastuzumab deruxtecan may cause serious side effects. Call your doctor at once if you have:

  • chest tightness, wheezing, cough, new or worsening shortness of breath;

  • pounding heartbeats or fluttering in your chest;

  • fever, tiredness, dizziness;

  • swelling in your lower legs, sudden weight gain;

  • a light-headed feeling, like you might pass out;

  • low blood cell counts--fever, chills, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet; or

  • low potassium level--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects of fam-trastuzumab deruxtecan may include:

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.

Fam-trastuzumab deruxtecan dosing information

Usual Adult Dose for Breast Cancer:

5.4 mg/kg IV every 3 weeks (21-day cycle) until disease progression or unacceptable toxicity

-Administer the first infusion over 90 minutes; administer subsequent infusions over 30 minutes if prior infusions were well tolerated.
-Slow or interrupt the infusion rate if the patient develops infusion-related symptoms.
-Permanently discontinue therapy for severe infusion reactions.

Use: For the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received 2 or more prior anti-HER2-based regimens in the metastatic setting

What other drugs will affect fam-trastuzumab deruxtecan?

Other drugs may affect fam-trastuzumab deruxtecan, 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.

Frequently asked questions

Further information

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.