Enhertu (fam-trastuzumab deruxtecan-nxki)

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.

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

WARNING

INTERSTITIAL LUNG DISEASE and EMBRYO-FETAL TOXICITY

• Interstitial Lung Disease (ILD) and pneumonitis, including fatal cases, have been reported with Enhertu.Monitor for and promptly investigate signs and symptoms including cough, dyspnea, fever, and other new orworsening respiratory symptoms. Permanently discontinue Enhertu in all patients with Grade 2 or higherILD/pneumonitis. Advise patients of the risk and the need to immediately report symptoms.
• Embryo-Fetal Toxicity: Exposure to Enhertu during pregnancy can cause embryo-fetal harm. Advise patients of these risks and the need for effective contraception.

Enhertu can cause serious side effects.

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 FDA at 1-800-FDA-1088.

Recommended Dosage And Schedules

Do Not Substitute Enhertu For Or With Trastuzumab Or Ado-Trastuzumab Emtansine

• The recommended dosage of Enhertu is 5.4 mg/kg given as an intravenous infusion once every 3 weeks (21-day cycle) until disease progression or unacceptable toxicity.

First Infusion

• Administer infusion over 90 minutes.

Subsequent Infusions

• Administer over 30 minutes if prior infusions were well tolerated.
• Slow or interrupt the infusion rate if the patient develops infusion-related symptoms.
• Permanently discontinue Enhertu in case of severe infusion reactions.

Dose Modifications

• Management of adverse reactions may require temporary interruption, dose reduction, or treatment discontinuation of Enhertu as described in Tables 1 and 2.

Do Not Re-Escalate The Enhertu Dose After A Dose Reduction Is Made

• If a planned dose is delayed or missed, administer as soon as possible; do not wait until the next planned cycle.
• Adjust the schedule of administration to maintain a 3-week interval between doses. Administer the infusion at the dose and rate the patient tolerated in the most recent infusion.

Table 1: Dose Reduction Schedule

Table 2: Dose Modifications for Adverse Reactions

• Based on its mechanism of action, Enhertu can cause fetal harm when administered to a pregnant woman.
• There are no available data on the use of Enhertu in pregnant women.
• In postmarketing reports, use of a HER2-directed antibody during pregnancy resulted in cases of oligohydramnios manifesting as fatal pulmonary hypoplasia, skeletal abnormalities, and neonatal death.
• There is no data regarding the presence of fam-trastuzumab deruxtecan-nxki in human milk, the effects on the breastfed child, or the effects on milk production.
• Because of the potential for serious adverse reactions in a breastfed child, women should not breastfeed during treatment with Enhertu and for 7 months after the last dose.