Potential Risks of
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What is the most important information I should know about ENHERTU?

ENHERTU can cause side effects.

Some serious or life-threatening side effects may affect your lungs, heart, or white blood cell count, affecting
your ability to fight infection.

Pay special attention to new or worsening symptoms as they may be related to:

Call or see your healthcare provider right away if you develop any of the following signs and symptoms or if these symptoms get worse:

  • Cough
  • Trouble breathing or shortness of breath
  • Fever
  • Other new or worsening breathing symptoms (e.g., chest tightness, wheezing)

If lung problems develop, your healthcare provider may treat you with corticosteroid medicines.

  • Low white blood cell counts are common with ENHERTU and can sometimes be severe
  • Your healthcare provider will check your white blood cell counts before starting ENHERTU and before starting each dose
  • Tell your healthcare provider right away if you develop any signs or symptoms of an infection or have fever or chills during treatment with ENHERTU

Your healthcare provider will check your heart function before starting treatment with ENHERTU. Tell your healthcare provider right away if you get any of the following signs and symptoms:

  • New or worsening shortness of breath
  • Coughing
  • Feeling tired
  • Swelling of your ankles or legs
  • Irregular heartbeat
  • Sudden weight gain
  • Dizziness or feeling light-headed
  • Loss of consciousness

Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with ENHERTU

  • If you are able to become pregnant, your healthcare provider should do a pregnancy test before you start treatment with ENHERTU
  • Females who are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 7 months after the last dose
  • Males who have female partners that are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 4 months after the
    last dose

Your healthcare provider will check you for these problems during your treatment with ENHERTU. Your healthcare provider may reduce your dose, delay treatment, or completely stop treatment with ENHERTU if you have severe side effects.

Contact your healthcare provider right away if you develop any of these side effects, experience new symptoms, or if your current symptoms get worse.

Will my healthcare provider adjust my dose if I have side effects?

To help manage side effects, your healthcare provider may:

Lower your dose icon: white arrow pointing down against orange background Lower your dose icon: white arrow pointing down against orange background

Lower your dose

Delay your dose icon: white clock against green background Delay your dose icon: white clock against green background

Delay your dose

Stop ENHERTU Icon: white octagon (stop sign) against dark blue background Stop ENHERTU Icon: white octagon (stop sign) against dark blue background

Stop ENHERTU

What can I do to help manage side effects?

Tips to help with side effects

  • Try to eat 5 or 6 small meals and snacks each day instead of 3 large meals
  • Eat bland, easy-to-digest food and drinks
  • Avoid food and drinks that are too hot or too cold
  • Avoid strong smells, if possible
  • If you are vomiting, take deep, slow breaths and, if possible, get fresh air
  • Try to eat 5 or 6 small meals and snacks each day instead of 3 large meals
  • Eat foods that are low in fiber
  • Drink clear liquids to replace lost fluids. Check with your healthcare provider to figure out how much and what types of fluid might be best
  • Try activities such as meditation, which helps with relaxation and decreases stress
  • Plan rest time and try not to do too much
  • Try regular exercise during times when your energy level is high (according to your healthcare provider’s approval)
  • Let other people help you with everyday tasks
Before hair loss:
  • Talk to your healthcare provider about the possibility of hair loss
  • Consider cutting your hair short to feel more in control of hair loss
  • Be gentle when you wash your hair. Use a mild shampoo, such as baby shampoo
  • Avoid items such as electric hair dryers, hairspray, hair dyes, products to perm or relax hair, hair bands, and/or clips that can hurt your scalp
  • If you plan on buying a wig, you should do so while you still have hair
If hair loss occurs:
  • Protect your scalp
  • Cover your head to stay warm. You may feel colder if you lose your hair
  • Sleep on a satin pillow case. Satin creates less friction and may be more comfortable

What are the possible side effects of ENHERTU?

ENHERTU can cause serious side effects.
See "What is the most important information I should know about ENHERTU?".

The most common side effects of ENHERTU:

  • Nausea
  • Feeling tired
  • Vomiting
  • Hair loss
  • Constipation
  • Decreased appetite
  • Low red blood cell counts
  • Low white blood cell counts
  • Diarrhea
  • Cough
  • Low platelet counts

ENHERTU may cause fertility problems in males, which may affect the ability to father children. Talk to your healthcare provider if you have concerns about fertility.

These are not all of the possible side effects of ENHERTU. Call your doctor for medical advice about side effects. You may report side effects to Daiichi Sankyo at 1-877-437-7763 or to FDA at 1-800-FDA-1088.

Before you receive ENHERTU, tell your healthcare provider about all of your medical conditions, including if you:

  • Have lung or breathing problems.
  • Have signs or symptoms of an infection.
  • Have or have had any heart problems.
  • Are breastfeeding or plan to breastfeed. It is not known if ENHERTU passes into your breast milk. Do not breastfeed during treatment with ENHERTU and for 7 months after the last dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Harm to your unborn baby. Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with ENHERTU.

  • If you are able to become pregnant, your healthcare provider should do a pregnancy test before you start treatment with ENHERTU.
  • Females who are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 7 months after the last dose.
  • Males who have female partners that are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 4 months after the last dose.

Managing side effects with ENHERTU

Let your healthcare provider know right away if you are experiencing any side effects.

Your healthcare provider may take steps to help manage your side effects, including:

  • Slowing down, interrupting, or stopping ENHERTU treatment
  • Prescribing other medicines to help lessen side effects
  • Recommending lifestyle changes

Are there resources that I or my caregiver might find helpful?

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We offer materials and support for
patients and caregivers

View Resources
Would you like us to send you information about ENHERTU when it becomes available?

What is the most important information I should know about ENHERTU?
ENHERTU can cause serious side effects, including:
Lung problems that may be severe, life-threatening or that may lead to death.
If you develop lung problems your healthcare provider may treat you with corticosteroid medicines. Tell your healthcare provider right away if you get any of the following signs and symptoms:

  • Cough
  • Trouble breathing or shortness of breath
  • Fever
  • Other new or worsening breathing symptoms (e.g., chest tightness, wheezing)

Low white blood cell count (neutropenia). Low white blood cell counts are common with ENHERTU and can sometimes be severe. Your healthcare provider will check your white blood cell counts before starting ENHERTU and before starting each dose. Tell your healthcare provider right away if you develop any signs or symptoms of an infection or have fever or chills during treatment with ENHERTU.

Heart problems that may affect your heart’s ability to pump blood. Your healthcare provider will check your heart function before starting treatment with ENHERTU. Tell your healthcare provider right away if you get any of the following signs and symptoms:

  • New or worsening shortness of breath
  • Coughing
  • Feeling tired
  • Swelling of your ankles or legs
  • Irregular heartbeat
  • Sudden weight gain
  • Dizziness or feeling light-headed
  • Loss of consciousness

Your healthcare provider will check you for these side effects during your treatment with ENHERTU. Your healthcare provider may reduce your dose, delay treatment or completely stop treatment with ENHERTU if you have severe side effects.

Harm to your unborn baby. Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with ENHERTU.

  • If you are able to become pregnant, your healthcare provider should do a pregnancy test before you start treatment with ENHERTU.
  • Females who are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 7 months after the last dose.
  • Males who have female partners that are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for at least 4 months after the last dose.

Before you receive ENHERTU, tell your healthcare provider about all of your medical conditions, including if you:

  • Have lung or breathing problems.
  • Have signs or symptoms of an infection.
  • Have or have had any heart problems.
  • Are breastfeeding or plan to breastfeed. It is not known if ENHERTU passes into your breast milk. Do not breastfeed during treatment with ENHERTU and for 7 months after the last dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How will I receive ENHERTU?

  • You will receive ENHERTU into your vein through an intravenous (IV) line by your healthcare provider.
  • ENHERTU is given 1 time every three weeks (21-day treatment cycle).
  • Your healthcare provider will decide how many treatments you need.
  • Your healthcare provider may slow down or temporarily stop your infusion of ENHERTU if you have an infusion-related reaction, or permanently stop ENHERTU if you have severe infusion reactions.
  • If you miss a planned dose of ENHERTU, call your healthcare provider right away to schedule an appointment. Do not wait until the next planned treatment cycle.

What are the possible side effects of ENHERTU?
ENHERTU can cause serious side effects. See "What is the most important information I should know about ENHERTU?"

The most common side effects of ENHERTU include:

  • Nausea
  • Feeling tired
  • Vomiting
  • Hair loss
  • Constipation
  • Decreased appetite
  • Low red blood cell counts
  • Low white blood cell counts
  • Diarrhea
  • Cough
  • Low platelet counts

ENHERTU may cause fertility problems in males, which may affect the ability to father children. Talk to your healthcare provider if you have concerns about fertility.

These are not all of the possible side effects of ENHERTU. Call your doctor for medical advice about side effects. You may report side effects to Daiichi Sankyo at 1-877-437-7763 or to FDA at 1-800-FDA-1088.

What is ENHERTU?

ENHERTU is a prescription medicine used in adults to treat human epidermal growth factor 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.

ENHERTU was FDA approved for this use based on a clinical study that measured how many patients responded and how long they responded. ENHERTU is still being studied to confirm these results.

It is not known if ENHERTU is safe and effective in children.

Please click here for full Prescribing Information, including Boxed WARNINGS, and click here for Medication Guide.

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