Enhertu Side Effects

Generic name: fam-trastuzumab deruxtecan

Medically reviewed by Philip Thornton, DipPharm. Last updated on Oct 15, 2024.

Note: This document provides detailed information about Enhertu Side Effects associated with fam-trastuzumab deruxtecan. Some dosage forms listed on this page may not apply specifically to the brand name Enhertu.

Applies to fam-trastuzumab deruxtecan: intravenous powder for solution.

Precautions

It is very important that your doctor check your progress closely while receiving the medicine and at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood tests may be needed to check for unwanted effects.

Receiving this medicine while you are pregnant can harm your unborn baby. It may also cause birth defects if the father is receiving it when his sexual partner becomes pregnant. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting treatment. Female patients should use effective birth control during treatment with this medicine and for 7 months after the last dose. Male patients who have female partners should use effective birth control during treatment with this medicine and for 4 months after the last dose. If you think you have become pregnant while receiving the medicine, tell your doctor right away.

Talk with your doctor before receiving this medicine if you plan to have children. Some men who receive this medicine have become infertile (unable to have children).

Tell your doctor right away if you are having chest pain or tightness, chills, cough, fever, general feeling or discomfort or illness, thickening of bronchial secretions, or trouble breathing while receiving this medicine. These could be symptoms of a serious lung problem (eg, interstitial lung disease or pneumonitis).

This medicine can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
• Avoid contact sports or other situations where bruising or injury could occur.

This medicine may cause heart failure. Your doctor may test your heart before and during treatment. Contact your doctor right away if you have chest pain, increased coughing, trouble breathing, rapid weight gain, or swelling in your ankles or legs. These could be symptoms of heart failure.

Serious side effects of Enhertu

Along with its needed effects, fam-trastuzumab deruxtecan (the active ingredient contained in Enhertu) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking fam-trastuzumab deruxtecan:

Other side effects of Enhertu

Some side effects of fam-trastuzumab deruxtecan may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to fam-trastuzumab deruxtecan: intravenous powder for injection.

Hematologic adverse events

• Very common (10% or more): Anemia (e.g., anemia, hemoglobin decreased, hematocrit decreased, red blood cell count decreased) (31%), neutropenia (e.g., neutropenia, neutrophil count decreased) (30%), leukopenia (e.g., leukopenia, lymphopenia, white blood cell count decreased) (22%), thrombocytopenia (e.g., thrombocytopenia, platelet count decreased) (20%)^[Ref]

Immunologic

• Frequency not reported: As with all therapeutic proteins there is potential for immunogenicity^[Ref]

Ocular

• Very common (10% or more): Dry eye (11%)^[Ref]

Metabolic

• Very common (10% or more): Decreased appetite (32%), hypokalemia (12%)^[Ref]

Hepatic

• Very common (10% or more): Aspartate aminotransferase increased (14%), alanine aminotransferase increased (14%)^[Ref]

Respiratory

• Very common (10% or more): Cough (20%), dyspnea (13%), epistaxis (13%)
• Common (1% to 10%): Interstitial lung disease (ILD) (e.g., pneumonitis, ILD, respiratory failure, organizing pneumonia, acute respiratory failure, lung infiltration, lymphangitis, alveolitis), upper respiratory tract infection (e.g., influenza, influenza like illness, upper respiratory tract infection) (15%)^[Ref]

Other

• Very common (10% or more): Fatigue/asthenia (59%)^[Ref]

Nervous system

• Very common (10% or more): Headache (e.g., headache, sinus headache, migraine) (19%)^[Ref]

Cardiovascular

• Frequency not reported: Left ventricular dysfunction (LVEF)^[Ref]

Dermatologic

• Very common (10% or more): Alopecia (46%), rash (e.g., rash, rash pustular, rash maculopapular) (10%)^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (79%), vomiting (47%), constipation (35%), diarrhea (29%), abdominal pain (e.g., abdominal discomfort, GI pain, abdominal pain, abdominal pain lower, abdominal pain upper) (19%), stomatitis (e.g., stomatitis, aphthous ulcer, mouth ulceration, oral mucosa erosion, oral mucosa blistering) (14%), dyspepsia (12%)^[Ref]

See also:

Frequently asked questions

• What is the success rate of Enhertu in metastatic breast cancer?
• Is Enhertu a chemotherapy drug? What's Enhertu used for?

Further information

Enhertu side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer