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Enhertu is used to treat different kinds of cancer that have a protein called HER2, such as certain types of breast, lung, and stomach cancers. Common side effects include nausea and tiredness. Some side effects can be very dangerous. Call your healthcare provider right away if you have a fever or chills, cough, shortness of breath, sudden weight gain, unusual bleeding or bruising, or new or worsening breathing problems. Enhertu is an infusion given into your vein (IV) by your healthcare provider.

Uses

What is Enhertu used for?

Enhertu (fam-trastuzumab deruxtecan-nxki) is commonly used for treating different kinds of HER2-positive solid tumors, including certain types of breast cancer, non-small cell lung cancer (NSCLC), stomach cancer and esophageal cancer,. HER2 is a protein that some cancers express and it allows the cancer cells to grow more quickly. 

Learn more about How Enhertu Works for Breast Cancer.

Enhertu may also be used for other conditions as determined by your healthcare provider.

How does Enhertu work (mechanism of action)?

Enhertu is a type of medicine known as an antibody-drug conjugate (ADC). ADCs work as smart bombs to find cancer cells in the body that have (or express) a certain protein. Enhertu targets a protein called HER2. Once the medicine finds these cells, the different parts of the ADC work to help the trastuzumab deruxtecan, a chemotherapy, get absorbed inside of the cell to damage its DNA and make the cell die, which stops the tumor from spreading and growing. 

How is Enhertu supplied (dosage forms)?

Enhertu is available in an injectable form that is given by a healthcare provider.

How should I store Enhertu?

Enhertu is given by a healthcare provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of Enhertu?

The most common side effects of Enhertu are listed below. Tell your healthcare provider if you have any of these side effects that bother you. These side effects may vary depending on the condition that is being treated.

  • Nausea and vomiting
  • Blood disorders (see below)
  • Tiredness
  • Increased liver function tests
  • Hair loss
  • Constipation
  • Decreased appetite
  • Low potassium levels
  • Diarrhea
  • Muscle or bone pain
  • Stomach pain
  • Fever 

There may be other side effects of Enhertu that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of Enhertu?

While less common, the most serious side effects of Enhertu are described below, along with what to do if they happen.

Severe Allergic Reactions. Enhertu may cause allergic reactions, which can be serious. Get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Lung Inflammation. Enhertu can cause inflammation in your lungs, also called interstitial lung disease. This can be serious or even life-threatening. Tell your healthcare provider right away if you have trouble breathing, shortness of breath, wheezing, or chest tightness. You may also have a cough and/or fever.

Blood Disorders. Enhertu can cause low levels of a type of white blood cell (called neutrophils), which is known as neutropenia. Enhertu can also cause a severely low number of platelets in your blood, also called thrombocytopenia. Neutrophils help prevent infection, whereas platelets help to form blood clots. Having a low level of neutrophils may increase your risk of infection. Having a low level of platelets may increase your risk of bleeding.. Keep all appointments to have your blood checked. Tell your healthcare provider right away if you have any of the following symptoms of blood disorders.

  • Fever, chills, or sweats
  • Sore throat, cough, or shortness of breath
  • Mouth or throat sores
  • Easy bruising or bleeding
  • Frequent infection
  • Unusual weakness or tiredness
  • Swollen lymph nodes
  • Bleeding that does not stop
  • Nosebleeds

Infusion Reactions. Enhertu can cause reactions that can be serious when it is given to you. Your infusion may need to be slowed or stopped if you have these reactions. Tell your healthcare provider right away if you have any symptoms such as itching or nausea when you get your infusion.

Heart Failure. Enhertu may increase your risk of heart failure by causing issues with the left ventricle of your heart, also called left ventricular dysfunction. Tell your healthcare provider right away if you have any of the following symptoms of heart failure.

  • Shortness of breath or trouble breathing, especially while lying down
  • Swelling in your feet, ankles, or legs
  • Unusually fast weight gain
  • Unusual tiredness

Warnings & Precautions

Who should not use Enhertu?

Allergies to Ingredients. People who are allergic to any of the following should not use Enhertu.

  • Enhertu
  • Trastuzumab deruxtecan
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in Enhertu.

What should I know about Enhertu before using it?

Do not use Enhertu unless it has been prescribed by a healthcare provider. Your healthcare provider will store and administer the medicine.

What should I tell my healthcare provider before using Enhertu?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if Enhertu is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Kidney problems
  • Heart or lung problems
  • An infection

Pregnancy. Enhertu may cause harm to an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. You must not be pregnant before starting Enhertu. If you can become pregnant, use effective birth control during treatment with Enhertu and for seven months after your last dose. If you are a male who has a female partner that can become pregnant, use effective birth control during treatment with Enhertu and for four months after your last dose.

Infertility. Enhertu may cause fertility problems in people who were assigned male at birth. Talk with your healthcare provider if this is a concern for you. 

Breastfeeding. Do not undergo treatment with Enhertu while you are breastfeeding and for seven months after your last dose. It is not known if Enhertu passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed.

How can I get more information about Enhertu?

For more information about Enhertu, you can visit the manufacturer’s website at www.enhertu.com or call them at 833-364-3788.

Interactions

Does Enhertu interact with foods or drinks?

There are no known interactions between Enhertu and foods or drinks.

It is unknown if drinking alcohol will affect Enhertu.

Does Enhertu interact with other medicines (drug interactions)?

There are no known interactions between Enhertu and other medicines. Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

This may not be a complete list of medicines that can interact with Enhertu. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much Enhertu?

If you or someone else has used too much Enhertu, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of Enhertu?

Enhertu is given by a healthcare provider in a hospital. Your healthcare provider will make sure you are receiving Enhertu as scheduled. If you miss an appointment, call your healthcare provider right away to reschedule. 

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