This medication is used to treat certain types of cancer (such as breast, lung). It works by slowing or stopping the growth of cancer cells.

Read the Medication Guide provided by your pharmacist before you start using datopotamab deruxtecan and each time you get a treatment. If you have any questions, ask your doctor or pharmacist.

This medication is given by injection into a vein by a health care professional. It is given as directed by your doctor, usually once every 21 days. The first dose is injected slowly into a vein over 90 minutes. Later doses may be given over 30 minutes. The dosage is based on your medical condition, weight, and response to treatment.

Infusion reactions may happen during the infusion of this drug and for some time afterward. Your doctor may prescribe other medications (such as acetaminophen, antihistamines, drugs used to treat nausea) before each treatment to help prevent these side effects. Tell your doctor right away if you have any symptoms of infusion reactions such as cough, wheezing, nausea, or vomiting. Your doctor may give you other medications to help with these side effects or may slow down or stop your treatment for some time.

Use this medication regularly to get the most benefit from it. To help you remember, mark your calendar with a reminder.

See also How to Use section.

Dry eye, tiredness, hair loss, muscle/joint pain, constipation, nausea, or vomiting may occur. Nausea and vomiting can be severe. In some cases, your doctor may prescribe medication to prevent or relieve nausea and vomiting. Eating several small meals, not eating before treatment, or limiting activity may help lessen some of these effects. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To prevent or treat dry eyes, your doctor may direct you to use an eye lubricant, such as artificial tears. Ask your doctor or pharmacist for more information.

Pain or sores in the mouth and throat may also occur. To reduce the risk of getting mouth sores when you start datopotamab deruxtecan, your doctor may prescribe a mouthwash that contains a steroid medication. Brush your teeth carefully/gently, avoid using mouthwash that contains alcohol, and rinse your mouth often with cool water mixed with baking soda or salt. It may also be best to eat soft, moist foods.

People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

Tell your doctor right away if you have any serious side effects, including:

• eye pain/redness/swelling/irritation
• eye discharge
• vision changes (such as blurred vision, sensitivity to light)

Although this medication is used to treat certain types of lung cancers, it may rarely cause other serious (possibly fatal) lung problems. Tell your doctor right away if you have any new or worsening shortness of breath, cough, fever, or chest tightness.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using datopotamab deruxtecan, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• eye problems
• kidney disease
• liver disease
• lung/breathing problems

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using datopotamab deruxtecan. Datopotamab deruxtecan may harm an unborn baby. Your doctor should order a pregnancy test before you start this medication. Women using this medication should ask about the use of reliable forms of birth control during treatment and for 7 months after the last dose. Men using this medication should ask about the use of reliable forms of birth control during treatment and for 4 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this medication and for 1 month after the last dose. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as complete blood count, liver function, eye exam) may be done before you start using this medication and while you are using it. Keep all medical and lab appointments. Consult your doctor for more details.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Not applicable. This medication is given in a hospital or clinic and will not be stored at home.