Care During Chemotherapy and Beyond



Generic Name: Fam-trastuzumab deruxtecan-nxki

Enhertu® is the trade name for Fam-trastuzumab deruxtecan-nxki. In some cases, health care professionals may use the trade name Enhertu® when referring to the generic drug name Fam-trastuzumab deruxtecan-nxki.

Drug Type: Enhertu® is an anti-HER2 monoclonal antibody combined with a topoisomerase I inhibitor (for more detail, see "How Enhertu Works" section below).

What Enhertu® Is Used For

Enhertu® is a prescription medicine used in adults to treat human epidermal growth receptor 2 (HER2)-positive breast cancer that cannot be removed by surgery or that has spread to other parts of your body (metastatic), and who have received two or more prior anti-HER2 breast cancer treatments.

Note: If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.

How Enhertu® Is Given

  • Enhertu® is given through an infusion into a vein (intravenous, IV).
  • Enhertu® is given once every three weeks (21-day treatment cycle).
  • The amount of Enhertu® that you will receive depends on many factors, including your weight, your general health or other health problems, and the type of cancer or condition you have. Your doctor will determine your exact dosage and schedule.

Side Effects

Important things to remember about the side effects of Enhertu®:

  • Most people will not experience all of the Enhertu® side effects listed.
  • Enhertu® side effects are often predictable in terms of their onset, duration, and severity.
  • Most Enhertu® side effects will improve after therapy is complete.
  • Enhertu® side effects may be quite manageable. There are options to minimize or prevent the side effects of Enhertu®.

The following side effects are common (occurring in greater than 30%) for patients taking Enhertu®:

These are less common side effects (occurring in 10-29%) for patients receiving Enhertu®:

Some severe rare possible side effects of Enhertu® include:

  • Lung problems
  • Heart problems affecting left ventricular ejection fraction (LVEF)

Not all side effects are listed above. Side effects that are very rare -- occurring in less than about 10 percent of patients -- are not listed here. But you should always inform your health care provider if you experience any unusual symptoms.

When to Contact Your Doctor or Health Care Provider

Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:

  • Fever of 100.4º F (38º C) or higher, chills (possible signs of infection)
  • Cough, trouble breathing or shortness of breath, other new or worsening breathing symptoms (e.g., chest tightness, wheezing)
  • Feeling tired, swelling or your ankles or legs, irregular heartbeat, sudden weight gain, dizziness or feeling light-headed, loss of consciousness

The following symptoms require medical attention, but are not an emergency. Contact your health care provider within 24 hours of noticing any of the following:

  • Signs of infection: fever, chills, very bad sore throat, ear or sinus pain, cough with or without sputum, pain with passing urine, wounds that will not heal
  • Nausea (interferes with ability to eat and unrelieved with prescribed medication)
  • Vomiting (vomiting more than 4-5 times in a 24-hour period)
  • Diarrhea (4-6 episodes in a 24-hour period)
  • Unusual bleeding or bruising
  • Black or tarry stools, or blood in your stools
  • Blood in the urine
  • Pain or burning with urination
  • Extreme fatigue (unable to carry on self-care activities)
  • Mouth sores (painful redness, swelling or ulcers)

Always inform your health care provider if you experience any unusual symptoms.


  • Before starting Enhertu® treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.).
  • Before you receive Enhertu®, tell your health care provider if you have lung or breathing problems, signs or symptoms of an infection, have or have had any heart problems.
  • Do not receive any kind of immunization or vaccination without your doctor's approval while taking Enhertu®.
  • Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment. Enhertu® may be hazardous to the fetus. Women who are pregnant or become pregnant must be advised of the potential hazard to the fetus.
  • For women: use contraceptives, and do not conceive a child (get pregnant) while taking Enhertu®. Barrier methods of contraception, such as condoms, are recommended. Verify pregnancy status prior to treatment initiation. Effective contraception should be used during treatment with Enhertu® and for at least 7 months after the last dose of Enhertu®.
  • For men: effective contraception should be used during treatment with Enhertu® and for at least 4 months after the last dose of Enhertu®.
  • Avoid breastfeeding while taking Enhertu® and for up to 7 months after stopping the medication.

Self-Care Tips

  • Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
  • You may be at risk of infection so try to avoid crowds or people with colds, and report fever or any other signs of infection immediately to your health care provider.
  • Wash your hands often.
  • To help treat/prevent mouth sores, use a soft toothbrush, and rinse three times a day with 1 teaspoon of baking soda mixed with 8 ounces of water.
  • Use an electric razor and a soft toothbrush to minimize bleeding.
  • Avoid contact sports or activities that could cause injury.
  • To reduce nausea, take anti-nausea medications as prescribed by your doctor, and eat small, frequent meals.
  • Follow regimen of anti-diarrhea medication as prescribed by your health care professional.
  • Eat foods that may help reduce diarrhea (see managing side effects - diarrhea).
  • Acetaminophen or ibuprofen may help relieve discomfort from fever, headache and/or generalized aches and pains. However, be sure to talk with your doctor before taking it.
  • Avoid sun exposure. Wear SPF 15 (or higher) sunblock and protective clothing.
  • In general, drinking alcoholic beverages should be kept to a minimum or avoided completely. You should discuss this with your doctor.
  • Get plenty of rest.
  • Maintain good nutrition.
  • Remain active as you are able. Gentle exercise is encouraged such as a daily walk.
  • If you experience symptoms or side effects, be sure to discuss them with your health care team. They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and Testing While Taking Enhertu®

You will be checked regularly by your doctor while you are taking Enhertu® to monitor side effects and check your response to therapy. Periodic blood work will be obtained to monitor your complete blood count (CBC) as well as the function of other organs (such as your kidneys, liver, and heart) will also be ordered by your doctor.

How Enhertu® Works

Targeted therapy is the result of about 100 years of research dedicated to understanding the differences between cancer cells and normal cells. To date, cancer treatment has focused primarily on killing rapidly dividing cells because one feature of cancer cells is that they divide rapidly. Unfortunately, some of our normal cells divide rapidly too, causing multiple side effects.

Targeted therapy is about identifying other features of cancer cells. Scientists look for specific differences in the cancer cells and the normal cells. This information is used to create a targeted therapy to attack the cancer cells without damaging the normal cells, thus leading to fewer side effects. Each type of targeted therapy works a little bit differently but all interfere with the ability of the cancer cell to grow, divide, repair and/or communicate with other cells.

There are different types of targeted therapies, defined in three broad categories. Some targeted therapies focus on the internal components and function of the cancer cell. The targeted therapies use small molecules that can get into the cell and disrupt the function of the cells, causing them to die. There are several types of targeted therapy that focus on the inner parts of the cells. Other targeted therapies target receptors that are on the outside of the cell. Therapies that target receptors are also known as monoclonal antibodies.

Enhertu® is made up of two cancer-fighting agents: an antibody attached to chemotherapy. Trastuzumab is a monoclonal antibody targeting HER2 receptor on cancer cells. The HER2 gene produces a protein receptor on the cell surface that signals normal cell growth by telling the cell to divide and multiply. Some cancerous breast tissue has too much HER2 (HER2/neu overexpression), triggering the cells to divide and multiply very rapidly. Trastuzumab attaches to the HER2 receptors to prevent cells from multiplying, preventing further cancer growth and slowing cancer progression. It may also work by stimulating an immune mechanism.

Enhertu® incorporates the HER2 targeted actions of trastuzumab with a topoisomerase I inhibitor. This allows for selective delivery into HER2 overexpressing cells, resulting in DNA damage and cell death.

Note: We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice. is designed to provide the latest information about chemotherapy to patients and their families, caregivers and friends. For information about the 4th Angel Mentoring Program visit