Enhertu is a brand-name prescription drug. It’s FDA-approved to treat HER2-positive (HER2+) breast cancer in women and men. (HER2+ means the cancer cells have abnormally high levels of a protein called HER2, which promotes cell growth.) Enhertu can be used in people who’ve had at least two previous HER2 treatments for metastatic breast cancer.

Enhertu can treat HER2+ breast cancer that’s either:

  • metastatic (has spread to other parts of the body, such as the bones, liver, brain, or lungs), or
  • unresectable (can’t be treated with surgery)

Although Enhertu is approved for use in both women and men, it’s important to note that Enhertu hasn’t been studied in men. Male and female breast tissue is largely the same, but it’s still unknown exactly how effective or safe this drug is in men.

Enhertu contains the combination drug fam-trastuzumab deruxtecan-nxki, which includes two active drugs. The first is fam-trastuzumab deruxtecan, an HER2 antibody. The second drug is DXd, which is a topoisomerase I inhibitor (a type of chemotherapy). The HER2 antibody helps the chemotherapy drug reach the HER2 cancer cells. These drugs then damage the cancer cells, causing them to die.

Enhertu comes as a powder that’s mixed with liquid to form a solution. It’s given as an intravenous (IV) infusion, which goes into your vein. (An infusion is an injection that lasts a certain length of time.) You’ll receive Enhertu at your doctor’s office or a hospital.

FDA approval

The Food and Drug Administration (FDA) first approved Enhertu in 2019 for use in adults with HER2+ breast cancer. It’s important to note that the drug received accelerated approval from the FDA.

Accelerated approval is based on information from early clinical trials of the drug. The FDA’s decision for full approval of Enhertu will be made after additional clinical trials have been completed.

Typically, drugs receive approval from the FDA after extensive studies have been completed. But for some drugs, such as Enhertu, a drug’s approval is granted before all of the studies have been done. Accelerated approval is granted for certain drugs used to treat conditions that don’t have a lot of successful treatment options.

For example, with HER2+ breast cancer, there aren’t many effective treatment choices for people who’ve had two or more previous HER2 treatments for metastatic breast cancer.

Effectiveness

For information on Enhertu’s effectiveness, see the “Enhertu uses” section.

Enhertu is available only as a brand-name medication. It’s not currently available in generic form.

A generic drug is an exact copy of the active drug in a brand-name medication. Generics usually cost less than brand-name drugs.

Enhertu can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Enhertu. These lists don’t include all possible side effects.

For more information on the possible side effects of Enhertu, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to report to the FDA a side effect you’ve had with Enhertu, you can do so through MedWatch.

Mild side effects

Mild side effects of Enhertu can include:*

  • nausea and vomiting
  • fatigue (lack of energy)
  • headache
  • upper respiratory infection, such as the common cold
  • decreased appetite
  • cough
  • mouth sores
  • hair loss (see “Side effect details” below)
  • digestive problems, including indigestion (upset stomach), constipation, and diarrhea (see “Side effect details” below)

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Enhertu. To learn about other mild side effects, talk with your doctor or pharmacist, or view Enhertu’s Medication Guide.

Serious side effects

Serious side effects from Enhertu aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects are explained below in “Side effect details.” These include:

* Enhertu has boxed warnings for these side effects. A boxed warning is the most serious warning from the FDA. For more information, see “FDA warnings” at the beginning of this article.

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on some of the side effects this drug may cause.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Enhertu. Symptoms of a mild allergic reaction may include:

  • flushing (warmth and redness in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have a severe allergic reaction to Enhertu. Call 911 or your local emergency phone number if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious lung conditions

Enhertuhas a boxed warning for serious lung conditions, including interstitial lung disease and pneumonitis. A boxed warning is the most serious warning from the FDA. It alerts doctors and patients about a drug’s effects that may be dangerous.

With interstitial lung disease, you have scarring and inflammation (swelling or damage) in your lungs. This is a serious side effect and can even be fatal. Symptoms may vary depending on the condition but can include cough, fever, and shortness of breath.

In clinical studies:

  • 9% of people taking Enhertu had interstitial lung disease
  • 2.6% of people taking Enhertu died due to complications of interstitial lung disease

Enhertu wasn’t compared with any other drugs or a placebo in these studies.

If you develop cough, shortness of breath, fever, or any other change in breathing, call your doctor right away. These symptoms may be a sign of interstitial lung disease or other serious lung conditions. Your doctor will likely have you stop taking Enhertu temporarily until your symptoms get better. Or they may have you switch to a different drug to treat your breast cancer.

If you have concerns about your risk for interstitial lung disease, talk with your doctor.

Blood disorders

Enhertu can cause blood disorders in some people. These disorders can include anemia, neutropenia, leukopenia, and thrombocytopenia. With each of these conditions, you have a low level of a certain type of blood cell.

In a clinical study of people taking Enhertu:

  • 30% had neutropenia (low level of white blood cells)
  • 31% had anemia (low level of red blood cells)
  • 22% had leukopenia (low level of white blood cells)
  • 20% had thrombocytopenia (low level of platelets, a type of blood cell)

Enhertu wasn’t compared with any other drugs or a placebo in this study.

Your doctor will order blood tests before each dose of your Enhertu treatment to check for blood disorders. Depending on your test results, your doctor may have to temporarily stop your Enhertu treatment until your levels return to normal. This is to help reduce your risk of side effects from the drug.

Talk with your doctor if you have concerns about your risk for these conditions.

Reduced heart function

Enhertu may affect left-sided heart function for some people, which causes the left side of the heart to not work properly. When this happens, blood can back up into your lungs.

Ejection fraction is a measurement used to see what percentage of blood flows out of your heart each time it contracts. Your doctor can check how well the left side of your heart pumps blood by looking at what is known as the left ventricular ejection fraction (LVEF).

In a clinical study, 0.9% of people taking Enhertu had their LVEF drop after taking the drug. A drop in LVEF could lead to heart failure in some cases. It’s important to note that none of these people in the clinical study developed symptoms of heart failure.

Enhertu wasn’t compared with any other drugs or a placebo in this study.

Examples of symptoms that may mean your heart isn’t pumping enough blood include:

  • cough
  • feeling dizzy or lightheaded
  • feeling tired
  • fluid retention, especially in the ankles or legs
  • shortness of breath
  • sudden weight gain

Call your doctor right away if you experience any of these symptoms.

Your doctor will continue to monitor your LVEF during your Enhertu treatment. If your LVEF drops too low or if you develop symptoms of heart failure, they’ll likely have you stop taking Enhertu and switch to a different medication.

Before taking Enhertu, talk with your doctor about any current heart problems you may have, or if you have a history of heart problems.

Hair loss

Hair loss is one of the most common side effects of Enhertu. It’s also a common side effect for many other drugs used to treat breast cancer.

In a clinical study, 46% of people taking Enhertu experienced hair loss. Enhertu wasn’t compared with any other drugs or a placebo in this study.

Besides hair loss on the head, Enhertu can also affect hair on other areas of your body, such as your legs, arms, and eyelashes. Your hair should begin to grow back after your treatment with Enhertu is completed.

If you’re concerned about hair loss during your Enhertu treatment, talk with your doctor.

Digestive problems

Enhertu can cause digestive problems in some people. In a clinical study:

  • 35% of people taking Enhertu had constipation
  • 29% of people taking Enhertu had diarrhea
  • 12% of people taking Enhertu had indigestion

Enhertu wasn’t compared with any other drugs or a placebo in this study.

If you’re concerned about digestive problems during your Enhertu treatment, talk with your doctor. They may suggest ways to relieve your symptoms with or without using a new medication. They may also recommend discussing other treatment options for your condition.

The Enhertu dosage your doctor prescribes will depend on several factors. These include:

  • other medical conditions you may have
  • how well your body tolerates Enhertu
  • your weight (your dose is determined by your weight in kilograms)

Typically, your doctor will start you on the recommended dosage of 5.4 milligrams (mg) of Enhertu per kilogram (kg) of body weight.

Your doctor will ultimately prescribe the dosage that provides the desired effect. Your doctor may lower your dose if you get certain side effects.

The following information describes dosages that are commonly used or recommended. However, your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Enhertu comes as a powder that’s mixed with liquid to form a solution. It’s given as an intravenous (IV) infusion, which goes into your vein. (An infusion is an injection that lasts a certain length of time.) You’ll receive Enhertu at your doctor’s office or a hospital.

Enhertu is usually prescribed at a dosage of 5.4 mg/kg.

Dosage for breast cancer

To treat HER2+ breast cancer, in most cases your dose will be your weight in kg multiplied by 5.4. For example, someone who weighs 150 lb (68 kg) would receive a dose of 367 mg of Enhertu.

Enhertu is typically given once every 3 weeks. You’ll continue taking it for as long as your doctor prescribes. You’ll likely continue treatment with Enhertu until your cancer gets worse or you develop side effects that affect your daily life.

If you experience negative reactions to Enhertu, your doctor may adjust your dosage to better fit your needs.

Your first infusion will last 90 minutes. After that, your infusions will typically be 30 minutes. The length of your infusion may vary depending on how you react to Enhertu.

What if I miss a dose?

To make sure you don’t miss an appointment, try setting a reminder on your phone. If you can’t make your appointment, call your doctor’s office as soon as possible to reschedule.

Will I need to use this drug long term?

The length of Enhertu treatment can vary. It’s possible that you may take the drug long term. In clinical studies, at least half of the people using Enhertu took it for 7 months or longer.

Your doctor will determine the length of treatment that’s safe and effective for you. In general, you’ll continue treatment with Enhertu until either your cancer gets worse or you develop side effects that have a major impact on your daily life.

Enhertu comes as a powder that’s mixed with liquid to form a solution. It’s administered as an intravenous (IV) infusion, which goes into your vein. (An infusion is an injection that lasts a certain length of time.) You’ll receive Enhertu at your doctor’s office or a hospital.

Your first infusion will last 90 minutes. After that, your infusions will typically be 30 minutes. The length of your infusion may vary depending on how you react to Enhertu.

When it’s given

Enhertu is typically given every 3 weeks. To help make sure you don’t miss an appointment to have your infusion, try setting a reminder on your phone. You can also put your treatment schedule on a calendar.

Other drugs are available that can treat your condition. Some may be a better fit for you than others. If you’re interested in finding an alternative to Enhertu, talk with your doctor. They can tell you about other medications that may work well for you.

Note: Some of the drugs listed here are used off-label to treat this specific condition. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Alternatives for HER2-positive breast cancer

Examples of other drugs that may be used to treat HER2-positive (HER2+) breast cancer include:

  • trastuzumab (Herceptin)
  • ado-trastuzumab emtansine (Kadcyla)
  • neratinib (Nerlynx)
  • pertuzumab (Perjeta)
  • lapatinib (Tykerb)
  • tamoxifen
  • chemotherapy drugs, including:
    • docetaxel (Taxotere)
    • paclitaxel
    • carboplatin
    • capecitabine (Xeloda)
    • vinorelbine

You may wonder how Enhertu compares with other medications that are prescribed for similar uses. Here we look at how Enhertu and Herceptin are alike and different.

Ingredients

Enhertu contains the active drug fam-trastuzumab deruxtecan-nxki. Herceptin contains the active drug trastuzumab.

Uses

Here is a list of conditions that the Food and Drug Administration (FDA) has approved Enhertu and Herceptin to treat in adults.

  • Both Enhertu and Herceptin are FDA-approved to treat:
    • HER2-positive (HER2+) breast cancer that’s metastatic (has spread to other parts of the body)
  • Enhertu is also FDA-approved to treat:
    • HER2+ breast cancer that’s unresectable (can’t be treated with surgery)
  • Herceptin is also FDA-approved to treat:
    • HER2+ gastric (stomach) cancer that’s metastatic
    • HER2+ breast cancer that isn’t metastatic (for this condition, Herceptin may be used alone or with other medications)

Drug forms and administration

Enhertu and Herceptin both come as a powder that’s mixed with liquid to form a solution. They’re both given as an intravenous (IV) infusion, which goes into your vein. (An infusion is an injection that lasts a certain length of time.) You’ll receive Enhertu or Herceptin at your doctor’s office or a hospital.

Side effects and risks

Enhertu and Herceptin have some similar side effects and others that vary. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Enhertu, with Herceptin, or with both drugs (when taken individually).

  • Can occur with Enhertu:
    • hair loss
    • decreased appetite
    • cough
    • mouth sores
  • Can occur with Herceptin:
    • chills
    • fever
    • muscle and joint pain
    • increased blood pressure
    • dizziness
  • Can occur with both Enhertu and Herceptin:
    • nausea and vomiting
    • digestive problems, including indigestion (upset stomach), constipation, and diarrhea
    • fatigue (lack of energy)
    • headache

Serious side effects

These lists contain examples of serious side effects that can occur with Enhertu, with Herceptin, or with both drugs (when taken individually).

  • Can occur with Enhertu:
  • Can occur with Herceptin:
    • reaction to the infusion or lung problems†
  • Can occur with both Enhertu and Herceptin:
    • allergic reactions
    • blood disorders
    • reduced heart function†
    • harm to a fetus‡

* Enhertu has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. For more information, see “FDA warnings” at the beginning of this article.

Herceptin has boxed warnings for these side effects.

‡ Both Enhertu and Herceptin have a boxed warning for harm to a fetus.

Effectiveness

These drugs haven’t been directly compared in clinical studies. However, studies have found both Enhertu and Herceptin to be effective for treating HER2+ breast cancer.

Costs

According to estimates on WellRx.com, Herceptin generally costs less than Enhertu. The actual price you’ll pay for either drug depends on your insurance plan, your location, and if applicable, the pharmacy you use.

Enhertu and Herceptin drug are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

Herceptin is a biologic drug, which means it’s made from parts of living organisms. It has a biosimilar available called trastuzumab-anns (Kanjinti). A biosimilar is a medication that’s similar to a brand-name drug. Biosimilars are also created from parts of living organisms. They may cost less than brand-name medications.

Enhertu and Tykerb are prescribed for similar uses. Here’s a look at how are these drugs are alike and different.

Ingredients

Enhertu contains the active drug fam-trastuzumab deruxtecan-nxki. Tykerb contains the active drug lapatinib.

Uses

Here is a list of conditions that the Food and Drug Administration (FDA) has approved Enhertu and Tykerb to treat:

  • Enhertu and Tykerb are both FDA-approved to treat metastatic HER2-positive (HER2+) breast cancer in women and men. (Metastatic means the cancer has spread to other parts of the body, such as the bones, liver, brain, or lungs.)
    • For this purpose, Enhertu is used in adults who’ve had at least two previous HER2 treatments for metastatic breast cancer.
    • For this purpose, Tykerb is used in adults who’ve had at least one previous treatment that included anthracyclines, taxanes, and trastuzumab.
  • Enhertu is also FDA-approved for use in men and women with HER2+ breast cancer that’s unresectable (can’t be treated with surgery). For this purpose, Enhertu can be used in adults who’ve had at least two previous HER2 treatments for metastatic breast cancer.

Drug forms and administration

Enhertu comes as a powder that’s mixed with liquid to form a solution. It’s given as an intravenous (IV) infusion. (An infusion is an injection into your vein that’s slowly dripped in over time.)

Tykerb is a tablet that’s typically taken once a day. It’s common for Tykerb to be taken with either capecitabine (Xeloda) or letrozole (Femara).

Side effects and risks

Enhertu and Tykerb have some similar side effects and others that vary. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Enhertu, with Tykerb, or with both drugs (when taken individually).

  • Can occur with Enhertu:
    • digestive problems, including indigestion (upset stomach) and constipation
    • hair loss
    • cough
  • Can occur with Tykerb:
    • rash, redness, or blisters on the palms of your hands or soles of your feet
    • rash on any area of the body
    • shortness of breath
  • Can occur with both Enhertu and Tykerb:
    • nausea and vomiting
    • diarrhea
    • mouth sores
    • decreased appetite
    • headache

Serious side effects

These lists contain examples of serious side effects that can occur with Tykerb or with both drugs (when taken individually).

* Tykerb has a boxed warning for severe liver damage. A boxed warning is the most serious warning from the FDA.

Enhertu has boxed warnings for these side effects. For more information, see “FDA warnings” at the beginning of this article.

Effectiveness

These drugs haven’t been directly compared in clinical studies. However, studies have found both Enhertu and Tykerb to be effective for treating HER2+ breast cancer.

Costs

According to estimates on WellRx.com, Enhertu generally costs more than Tykerb. The actual price you’ll pay for either drug depends on your insurance plan, your location, and if applicable, the pharmacy you use.

Enhertu and Tykerb are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

There are no known interactions between Enhertu and alcohol.

But certain side effects of Enhertu can be made worse if you drink alcohol. This includes diarrhea and headache.

If you drink alcohol, talk with your doctor about how much is safe for you to drink during your Enhertu treatment.

Enhertu is not known to interact with other medications. It’s also not known to interact with any herbs, supplements, or foods.

Enhertu and other medications

Before taking Enhertu, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Enhertu and herbs and supplements

There aren’t any herbs or supplements that have been specifically reported to interact with Enhertu. However, you should still check with your doctor or pharmacist before using any of these products while taking Enhertu.

Enhertu and foods

There aren’t any foods that have been specifically reported to interact with Enhertu. If you have any questions about eating certain foods with Enhertu, talk with your doctor.

The Food and Drug Administration (FDA) approves prescription drugs such as Enhertu to treat certain conditions. Enhertu may also be used off-label for other conditions. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Enhertu for breast cancer

Enhertu is FDA-approved to treat HER2-positive (HER2+) breast cancer in women and men. (HER2+ means the cancer cells have abnormally high levels of a protein called HER2, which promotes cell growth.) Enhertu can be used in people who’ve had at least two previous HER2 treatments for metastatic breast cancer.

Enhertu can treat HER2+ breast cancer that’s either:

  • metastatic (has spread to other parts of the body, such as the bones, liver, brain, or lungs), or
  • unresectable (can’t be treated with surgery)

Although Enhertu is approved for use in both women and men, it’s important to note that Enhertu hasn’t been studied in men. Male and female breast tissue is largely the same, but it’s still unknown exactly how effective or safe this drug is in men.

Effectiveness for breast cancer

One clinical study involved women with HER2+ breast cancer that couldn’t be surgically removed or was metastatic. All of the women with metastatic breast cancer had received two or more previous HER2 treatments.

In this study:

  • 4.3% of women taking Enhertu had a complete response to the drug. (A complete response is when tests show no more cancer in your blood.)
  • 56% of women taking Enhertu had a partial response to the drug. (A partial response means the amount of cancer in your body has decreased.)

For at least half of the women taking Enhertu, their response to the drug lasted 14.8 months or more before their cancer got worse.

Enhertu wasn’t compared with any other drugs or a placebo in this study.

Enhertu and children

Enhertu isn’t approved for use in children. Enhertu hasn’t been studied in children, so it’s not known if the drug is safe or effective for them to use.

As with all medications, the cost of Enhertu can vary. To find current prices for Enhertu in your area, check out WellRx.com.

The cost you find on WellRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and if applicable, the pharmacy you use.

It’s important to note that you’ll have to get Enhertu through your doctor’s office or at a specialty pharmacy. This type of pharmacy is authorized to carry specialty medications. These are drugs that may be expensive or may require help from healthcare professionals to be used safely and effectively.

Your insurance plan may require you to get prior authorization before it approves coverage for Enhertu. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide if the drug will be covered.

If you’re not sure if you’ll need to get prior authorization for Enhertu, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Enhertu, or if you need help understanding your insurance coverage, help is available.

Daiichi Sankyo Inc., the manufacturer of Enhertu, offers a program called ENHERTU4U. This program includes resources that may help lower the cost of the drug for you. For more information and to find out if you’re eligible for support, call 833-ENHERTU (833-364-3788) or visit the program website.

Generic version

Enhertu isn’t available in a generic form. A generic drug is an exact copy of the active drug in a brand-name medication. Generics tend to cost less than brand-name drugs.

Enhertu is FDA-approved to treat HER2-positive (HER2+) breast cancer in women and men. It can be used in people who’ve had at least two previous HER2 treatments for metastatic breast cancer.

Enhertu can treat HER2+ breast cancer that’s either:

  • metastatic (has spread to other parts of the body, such as the bones, liver, brain, or lungs), or
  • unresectable (can’t be treated with surgery)

About HER2+ breast cancer

Human epidermal growth factor receptor 2 (HER2) is a gene that makes proteins in the breast. HER2+ breast cancer occurs when HER2 cells in the breast tissue tell your body to make too many copies of the cells. This causes tumors to form. Cancers that are HER2+ tend to grow and spread quickly.

In many cases, these extra copies of the cells spread to other areas of the body. This means the cancer is metastatic.

What Enhurtu does

Enhertu contains the combination drug fam-trastuzumab deruxtecan-nxki, which includes two active drugs. The first is fam-trastuzumab deruxtecan, an HER2 antibody. The second drug is DXd, which is a topoisomerase I inhibitor (a type of chemotherapy). The HER2 antibody helps the chemotherapy to better reach the HER2 cells.

Once Enhertu reaches the HER2 cancer cells, it damages the cell DNA. This causes the cell to die, which can make your tumor shrink.

How long does it take to work?

Enhertu starts working right away. However, you may not notice that Enhertu is working. This is because the drug works to shrink your tumor, but it may not relieve symptoms you’re having from your cancer.

Your doctor may order certain tests, such as blood tests, to check how your cancer is responding to Enhertu.

Enhertu shouldn’t be used during pregnancy. This is because the drug may cause miscarriage or serious harm to a fetus. Enhertu has a boxed warning for this side effect. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

If you’re pregnant or planning a pregnancy, talk with your doctor about treatment options for your cancer.

Enhertu and fertility

In animal studies, Enhertu reduced fertility in males. In these studies, males who were given Enhertu had less ability to father offspring. It isn’t known if Enhertu reduces fertility in humans. Animal studies don’t always predict how a drug will affect humans.

Talk with your doctor if you have concerns about how Enhertu may affect your fertility.

You shouldn’t take Enhertu while pregnant. This is because Enhertu may cause miscarriage or serious harm to a fetus. The drug has a boxed warning for this side effect. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re using Enhertu.

For more information about taking Enhertu during pregnancy, see the “Enhertu and pregnancy” section above.

For women using Enhertu

If you’re able to become pregnant, your doctor will need to make sure you’re not pregnant before starting Enhertu. You’ll need to use birth control during your treatment and for at least 7 months after your last dose of Enhertu.

For men using Enhertu

If you have a female partner who could become pregnant, you’ll need to use birth control during your Enhertu treatment. You and your partner need to keep using birth control for at least 4 months after your last dose of Enhertu.

It’s unknown if Enhertu passes into breast milk. Because of the chance for serious harm to a breastfed child, you shouldn’t breastfeed while taking Enhertu. You should avoid breastfeeding for 7 months after your last dose.

Here are answers to some frequently asked questions about Enhertu.

Is Enhertu a chemotherapy drug?

Enhertu itself isn’t a chemotherapy drug. However, Enhertu contains the active drug DXd. This is a type of chemotherapy drug called a topoisomerase I inhibitor. The other active drug Enhertu contains is fam-trastuzumab deruxtecan, which is an HER2 antibody.

This combination of drugs makes Enhertu work differently than chemotherapy alone. The addition of the HER2 antibody allows the drug to better target the HER2 cancer cells in the body. Once Enhertu reaches the HER2 cancer cells, it damages the cell DNA. This causes the cell to die, which can help your tumor shrink.

Will Enhertu cure my cancer?

No, Enhertu won’t cure your cancer. There is currently no cure for cancer. However, many people taking Enhertu had their tumor shrink.

Also, some people taking Enhertu experienced a complete response. (A complete response is when tests show no more cancer in your blood.)

Talk with your doctor if you have questions about how Enhertu will treat your cancer.

Does Enhertu cause hair loss?

It’s possible. Hair loss is one of the most common side effects of Enhertu. It’s also a common side effect for many other drugs used to treat breast cancer.

In a clinical study, 46% of people taking Enhertu experienced hair loss. Enhertu wasn’t compared with any other drugs or a placebo in this study.

Your hair should begin to grow back after your treatment with Enhertu is completed. If you’re concerned about hair loss during your Enhertu treatment, talk with your doctor.

Can Enhertu be used by men with breast cancer?

Yes. Enhertu is approved for use in both women and men. However, it’s important to note that Enhertu hasn’t been studied in men. Although male and female breast tissue is largely the same, it’s still unknown exactly how effective or safe this drug is in men.

Some breast cancer medications, known as aromatase inhibitors, are only approved for use in women. Examples of aromatase inhibitors include:

Learn more about breast cancer in men.

This drug comes with several precautions.

FDA warnings

This drug has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Serious lung conditions

Taking Enhertu can raise your risk for serious lung conditions. These include interstitial lung disease or pneumonitis. These conditions can cause scarring and inflammation (swelling or damage) in your lungs.

Interstitial lung disease or pneumonitis may lead to hospitalization or even death.

Your doctor will monitor you closely for symptoms of serious lung conditions during your Enhertu treatment. These symptoms may vary depending on the condition but can include cough, fever, and shortness of breath. If you develop a serious lung condition during your treatment, your doctor may have you stop taking Enhertu.

Harm to a fetus

Taking Enhertu while pregnant may cause miscarriage or serious harm to a fetus. Your doctor will need to make sure you aren’t pregnant before starting Enhertu. You’ll also need to use effective birth control during treatment. And you’ll need to continue to use birth control for several months after you’re received your last dose of Enhertu.

Other precautions

Before taking Enhertu, talk with your doctor about your health history. Enhertu may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Symptoms of infection. You shouldn’t start taking Enhertu if you have an active infection. If you have an infection, talk with your doctor about your treatment options.
  • Heart problems. Enhertu can cause severe heart disease, including heart failure. If you have a history of heart disease, talk with your doctor before taking Enhertu.
  • Lung or breathing problems. Enhertu can cause severe and even life threatening lung problems (see FDA warning above). If you have a history of lung or breathing problems, talk with your doctor before beginning Enhertu treatment.
  • Allergic reaction. If you’ve had an allergic reaction to Enhertu or any of its ingredients, you shouldn’t take Enhertu. Ask your doctor what other medications may work for you.
  • Pregnancy. Enhertu is not safe to take during pregnancy. For more information, see the “Enhertu and pregnancy” section above.
  • Breastfeeding. It’s not safe to breastfeed while taking Enhertu. For more information, see the “Enhertu and breastfeeding” section above.

Note: For more information about the potential negative effects of Enhertu, see the “Enhertu side effects” section above.

The following information is provided for clinicians and other healthcare professionals.

Indications

Enhertu is approved for use in adults with HER2-positive (HER+) breast cancer that is unresectable or metastatic. It can be used in women and men who have previously been treated with two or more anti-HER2 therapies.

Administration

Enhertu is administered intravenously, in the hospital or clinic setting.

The usual dosage of Enhertu is 5.4 mg/kg, given every 3 weeks (a 21-day cycle). Duration varies per person and typically continues until the disease progresses or until toxicity prevents further treatment.

The first infusion is usually given over 90 minutes. Subsequent infusions are given over a 30-minute period, as long as the person tolerates the infusion rate. Dose modifications may be made if the person experiences adverse reactions.

Mechanism of action

Enhertu contains the HER2-directed antibody-drug conjugate fam-trastuzumab deruxtecan-nxki, and DXd, a topoisomerase I inhibitor. Enhertu binds to and cleaves HER2 on tumor cells. This causes damage to the DNA and results in apoptotic cell death.

Pharmacokinetics and metabolism

Absolute bioavailability is up to 35% following intravenous administration. Steady-state concentration is reached after the third cycle of medication.

Enhertu elimination half-life is approximately 5.83 days.

Contraindications

Enhertu doesn’t have any contraindications. Use caution in people with a history of serious hypersensitivity reaction to the drug or any of its components.

Storage

Enhertu should be stored in the refrigerator at 36°F to 46°F (2°C to 8°C). Store in the original container to protect from light. Do not freeze. Do not shake the reconstituted solution after dilution.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.