Key takeaways

  • Targeted chemotherapy: Enhertu combines a targeted antibody with a powerful chemotherapy drug to attack HER2-positive cancer cells directly.
  • Common but manageable side effects: Many people experience nausea, fatigue, and hair loss.
  • Long-term IV treatment: Enhertu is given as an IV infusion every 3 weeks. You will typically stay on the medication as long as it continues to work and your body tolerates it well.

If your doctor has recommended Enhertu, you may have questions about what it is, how it works, and what to expect during treatment.

This guide provides an overview of Enhertu to help you feel informed and empowered as you discuss your care plan with your healthcare team.

Enhertu is a brand-name prescription medication given as an intravenous (IV) infusion. The active ingredient in Enhertu is fam-trastuzumab deruxtecan-nxki.

To understand how Enhertu works, it helps to know that it is a type of medication called an antibody-drug conjugate (ADC). You can think of it as a targeted delivery system with two main parts:

  1. A monoclonal antibody: This part actively seeks out and attaches to cancer cells that have high amounts of a specific protein called HER2 on their surface.
  2. A chemotherapy drug: Once the antibody attaches to the HER2-positive cancer cell, it releases the chemotherapy directly inside the affected cell to destroy it.

Because it specifically targets HER2 proteins, Enhertu works differently from traditional, broad-acting chemotherapy.

Currently, Enhertu is only available as a brand-name biologic drug. There is no generic or biosimilar version available.

The Food and Drug Administration (FDA) has approved Enhertu to treat several specific types of cancer in adults. Your doctor may prescribe Enhertu if you have:

Enhertu is given by a healthcare professional as an IV infusion, which means the medication is slowly dripped into your vein over a set period.

  • Frequency: Infusions are usually scheduled once every 3 weeks.
  • Dose: Your specific dose is highly personalized. It is calculated based on your body weight in kilograms, the type of cancer being treated, and how well your body tolerates the medication.
  • Duration: You will typically continue receiving Enhertu as long as your body handles the treatment well and the medication continues to keep the cancer from progressing.

If you experience side effects, your doctor might pause your treatment temporarily or lower your dose to help your body recover.

Like all medications, Enhertu can cause side effects. How you react to the medication will be unique to you, but clinical trials have shown some common trends.

Common, mild side effects

Some of the most frequently reported side effects in clinical studies include:

Your care team can often provide supportive treatments, like anti-nausea medications, to help manage these symptoms effectively.

Serious side effects and boxed warnings

Enhertu carries boxed warnings, which are the FDA’s most serious type of safety alert. It’s important to be aware of these risks, so you can report any concerning symptoms to your doctor immediately.

  • Serious lung conditions: Enhertu can cause severe, life-threatening inflammation and scarring in the lungs, known as interstitial lung disease (ILD) or pneumonitis. Call your doctor right away if you develop a new or worsening cough, trouble breathing, or a fever.
  • Harm to an unborn baby: Enhertu can cause serious fetal harm or pregnancy loss if taken during pregnancy. Because of these risks, your doctor will verify you are not pregnant before starting treatment. If you or your partner can become pregnant, they’ll also typically recommend using effective birth control throughout treatment and for at least 4 to 7 months after your last infusion.

Other serious risks

Enhertu can also affect your heart function, specifically reducing how well your heart pumps blood (left ventricular dysfunction). Your doctor will likely monitor your heart health before and during your treatment.

It can also cause severely low levels of red blood cells, white blood cells, and platelets. Your doctor will monitor your blood counts with regular blood tests.

Key terms defined

Treatments like Enhertu can temporarily lower the levels of different cells in your blood. Your doctor will monitor these closely, but it helps to know what they are looking for:

  • Anemia (low red blood cells): Red blood cells carry oxygen throughout your body. A low red blood cell count can leave you feeling unusually exhausted, weak, or short of breath.
  • Thrombocytopenia (low platelets): Platelets help your blood clot. If you have a low platelet count, you might notice that you bruise more easily or experience unusual bleeding, like nosebleeds or bleeding gums.
  • Leukopenia (low white blood cells): Leukocytes are white blood cells, which help your body respond to infection. When your white blood cell counts are low, you have a higher risk of getting an infection.
  • Neutropenia (low neutrophil count): Neutrophils are a type of white blood cells, which help your body respond to infection. When your white blood cell counts are low, you have a higher risk of getting an infection. Febrile neutropenia is considered as a medical emergency.

Before starting Enhertu, have an open conversation with your doctor about your complete medical history.

  • Heart and lung history: Be sure to mention if you have a history of heart failure, lung disease, or breathing problems.
  • Active infections: Enhertu can weaken your immune system. If you have an active infection, your doctor will likely wait for it to clear before starting treatment.
  • Pregnancy and breastfeeding: Enhertu is not safe to receive during pregnancy or while breastfeeding. If you are pregnant, breastfeeding, or planning for either, be sure to talk with your doctor before starting treatment.
  • Drug interactions: Tell your doctor and pharmacist about all prescription drugs, over-the-counter medications, vitamins, and herbal supplements you take to help avoid interactions.

Cancer treatments can be expensive, and dealing with financial logistics is often stressful. The cost of Enhertu varies widely depending on your health insurance plan, your location, and where you receive infusions.

Because it is a specialized medication, your insurance company will likely require prior authorization before covering it. This means your doctor needs to explain to the insurance company why this specific drug is medically necessary for you.

Need help paying for Enhertu?

If you are feeling overwhelmed by the cost, support is available. The manufacturer offers a program called ENHERTU4U, which provides financial assistance resources and help with navigating insurance coverage. You can find out if you are eligible by calling 1-833-ENHERTU (1-833-364-3788) or visiting the official website.

» Find out more: Enhertu and cost

If you’re researching HER2-positive treatments, you might see other drugs mentioned, such as Herceptin (trastuzumab).

While they share an active drug and both target the HER2 protein, they aren’t exactly alike. Here is a quick breakdown of how they compare:

Enhertu
Herceptin
Enhertu
Herceptin

treating some HER2-positive, HER2-low, and HER2-mutant cancers

treating some HER2-positive cancers

trastuzumab (monoclonal antibody) and deruxtecan (chemotherapy)

trastuzumab (monoclonal antibody)

IV infusion

IV infusion

typically prescribed as a stand-alone treatment (monotherapy)

typically prescribed as a combination therapy alongside separate chemotherapy drugs

hair loss, severe nausea, and low blood cell counts

fever, nausea, and headache

interstitial lung disease (ILD) and pneumonitis, pregnancy complications, and left sided heart failure

cardiomyopathy, infusion reactions, pregnancy complications, and breathing problems

It’s possible. Hair loss was a commonly reported side effect in clinical studies of Enhertu and other drugs that contain chemotherapy.

Currently, advanced and metastatic cancers do not have a definitive cure. However, Enhertu is a highly effective treatment designed to shrink tumors, prevent the cancer from spreading further, and help manage the disease so you can maintain your quality of life for as long as possible.

Yes. While male breast cancer is rare, Enhertu is FDA approved for use in both males and females.

If you are considering Enhertu, here is a quick checklist of questions and topics to bring to your next appointment. Consider bookmarking this page or taking a screenshot of the list so it’s easy to reference later.

  • Confirm your HER2 status: Ask your doctor if your specific cancer type and HER2 status make Enhertu a good option for you.
  • Review your medical history: Discuss your complete medical history, paying special attention to any past heart, lung, or breathing issues.
  • Discuss side effect management: Ask about the plan for monitoring side effects (like blood tests and heart scans) and what supportive medications (like anti-nausea drugs) will be provided.
  • Check for interactions: Review all your current prescription medications, over-the-counter drugs, and supplements with your care team.
  • Explore financial support: Ask to speak with a social worker or financial navigator about prior authorizations and assistance programs like ENHERTU4U.

Disclaimer: While Medical News Today strives for factual, comprehensive, and current drug information, this article is not a substitute for a licensed healthcare professional’s expertise. Always consult a doctor before taking or discontinuing any medication. Drug information is subject to change and may not cover all uses, directions, precautions, warnings, interactions, reactions, or adverse effects. The lack of a warning does not guarantee a drug’s safety, effectiveness, or appropriateness for all patients or specific uses. Learn more about our approach to content integrity.