What is Enhertu® (fam-trastuzumab deruxtecan-nxki)?

Enhertu® (fam-trastuzumab deruxtecan-nxki) is a human epidermal growth factor receptor-2 (HER2) directed antibody and topoisomerase inhibitor conjugate, which means it combines an antibody with a chemotherapy medication. Enhertu may be used to treat patients with HER2+ breast cancer that is unresectable (cannot be removed by surgery) or metastatic (has spread to other parts of the body) and who were previously treated with at least two other therapies that target HER2.1,2

What is the active ingredient in Enhertu?

The active ingredient in Enhertu is fam-trastuzumab deruxtecan-nxki.

How does Enhertu work?

The fam-trastuzumab portion of Enhertu is a monoclonal antibody. This means it is designed to seek out and attach to a very specific cell in the body. In this case, the target is HER-2 positive breast cancer cells.

The other part of Enhertu is the deruxtecan-nxki. This drug is a type of chemotherapy called a topoisomerase inhibitor. By combining the antibody and chemotherapy medication together, the antibody portion helps to find and attach to the HER2+ breast cancer cells, and once attached, the chemotherapy portion is released to attack the cancer cell. Enhertu is given by intravenous infusion (IV) only.2

What are the side effects of Enhertu?

The most common side effects of Enhertu include:2

  • Nausea
  • Fatigue
  • Hair loss
  • Vomiting
  • Low counts of red blood cells (the cells involved in delivering oxygen throughout the body)
  • Low counts of white blood cells (the cells that help protect the body from infection)
  • Low platelet counts (the cells involved in blood clotting and stopping bleeding)
  • Diarrhea
  • Constipation
  • Decreased appetite
  • Cough

These are not all the possible side effects of Enhertu. Patients should talk to their doctor about what to expect with treatment with Enhertu.

Things to know about Enhertu

Enhertu may cause serious side effects, including interstitial lung disease (ILD) and pneumonitis (inflammation of the lungs). These conditions can be life-threatening in certain cases. If a person receiving Enhertu develops ILD/pneumonitis, their doctor will need to evaluate their condition. Tell your doctor as soon as possible if you notice any signs of ILD or pneumonitis, including:2

  • Cough
  • Shortness of breath
  • Fever
  • Other new or worsening respiratory symptoms

Enhertu may cause harm to a developing fetus. Women who are pregnant or planning to become pregnant should not take Enhertu. While receiving Enhertu, men with female partners who can become pregnant, and women who can become pregnant, should both use effective contraceptives during treatment and for a period of time after completing treatment (patients should discuss appropriate birth control methods, and how long they need to use them, with their doctor).

Additionally, because Enhertu may cause heart damage, heart function tests may be performed before and during treatment with Enhertu.

Patients should talk to their doctor if they have any questions, or if they have questions regarding their Enhertu regimen. Before starting treatment with Enhertu, patients should tell their doctor about all their health conditions, as well as any medications (prescription and over-the-counter), herbal supplements, and vitamins they are taking.

Read the prescribing information to learn more about Enhertu.

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Written by: Editorial Team | Last reviewed: October 2020.