Datopotamab deruxtecan

Datopotamab deruxtecan is used in adults to treat breast cancer that has spread to other parts of the body (metastatic), cannot be removed with surgery, or after other treatments did not work or stopped working.

Your doctor will confirm that you have the right type of tumor to be treated with datopotamab deruxtecan.

Datopotamab deruxtecan may also be used for reasons not mentioned in this medication guide.

Tell your doctor if you take other medicines or have other medical conditions or allergies.

You should not take datopotamab deruxtecan if you are allergic to it.

Tell your doctor if you have ever had:

• lung disease or breathing problems;
• eye problem; or
• use contact lenses.

Datopotamab deruxtecan can harm an unborn baby if the mother or the father is using datopotamab deruxtecan.

• If you are a woman, you may need a pregnancy test to make sure you are not pregnant. Use birth control while using this medicine and for at least 7 months after your last dose.
• If you are a man, use birth control if your sex partner is able to get pregnant. Keep using birth control for at least 4 months after your last dose.
• Tell your doctor right away if a pregnancy occurs.

Do not breastfeed while using this medicine, and for at least 1 month after your last dose.

Datopotamab deruxtecan may affect fertility in men or women.

Get emergency medical help if you have signs of an allergic reaction: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Datopotamab deruxtecan may cause serious side effects. Call your doctor right away if you have:

• fever, chills, cough with mucus, chest pain, feeling short of breath, wheezing, trouble breathing;
• dry eyes or watery eyes, blurred vision;
• signs of eye infection—swelling, redness, severe discomfort, crusting or drainage;
• feeling like something is in your eye; or
• blisters or ulcers in your mouth, red or swollen gums, trouble swallowing;

Common side effects of datopotamab deruxtecan may include:

• nausea, vomiting, constipation;
• tiredness;
• low blood calcium—muscle spasms or contractions, numbness or tingling (around your mouth, or in your fingers and toes);
• low blood cell counts—fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;
• hair loss;
• dry eyes; or
• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Your doctor will perform tests to make sure datopotamab deruxtecan is the right treatment for you.

Datopotamab deruxtecan is given as an infusion into a vein by a healthcare provider.

Datopotamab deruxtecan is given in a 21-day treatment cycle. You will receive an injection only on certain days of this cycle.

Your healthcare provider will decide how long you should be treated with datopotamab deruxtecan based on response.

You may be given other medications to help prevent serious side effects or an allergic reaction. Keep using these medicines for as long as your doctor has prescribed.

Use preservative free eye drops at least 4 times daily and as needed during treatment.

You may need frequent vision exams.

Use a steroid mouthwash to help prevent and treat mouth sores. Hold ice chips or ice water in the mouth during infusion.

Call your doctor for guidance if you miss an appointment for your datopotamab deruxtecan injection.

In a medical setting, an overdose would be treated quickly.

• Avoid wearing contact lenses during treatment with datopotamab deruxtecan.

Other drugs may affect datopotamab deruxtecan, including prescription and over-the-counter medicines, vitamins, and herbal products. Inform your doctor about all other medicines you are taking.