Ado-trastuzumab emtansine is used to treat a HER2-positive breast cancer. This medicine is used both for early breast cancer and for breast cancer that has spread to other parts of the body (metastatic).

Ado-trastuzumab emtansine is usually given after other treatments have failed.

Kadcyla (ado-trastuzumab) should not be used in place of Herceptin (trastuzumab).

Ado-trastuzumab emtansine may also be used for purposes not listed in this medication guide.

Tell your doctor if you have ever had:

• heart problems;
• liver disease (especially hepatitis B or C);
• bleeding or blood clotting disorder such as hemophilia; or
• asthma, chronic obstructive pulmonary disease (COPD), sleep apnea, or other breathing disorder.

You may need to have a negative pregnancy test before starting this treatment.

Ado-trastuzumab emtansine can harm an unborn baby if the mother or the father is using this medicine.

• If you are a woman, do not use ado-trastuzumab emtansine if you are pregnant. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 7 months after your last dose.
• If you are a man, use effective 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 while either the mother or the father is using ado-trastuzumab emtansine.

Do not breastfeed while using this medicine, and for at least 7 months after your last dose.

Use Ado-Trastuzumab Emtansine (Intravenous) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

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

Some side effects may occur during the injection. Tell your caregiver right away if you feel cold, light-headed, feverish or sweaty, or have chest tightness, rapid heartbeats, or trouble breathing.

Call your doctor at once if you have:

• easy bruising, unusual bleeding, purple or red spots under your skin;
• coughing up blood or vomit that looks like coffee grounds;
• bloody or tarry stools;
• chest pain, wheezing, dry cough;
• unusual tiredness, feeling light-headed;
• pale skin, cold hands and feet;
• numbness, tingling, or burning pain in your hands or feet;
• sudden numbness or weakness (especially on one side of the body), severe headache, slurred speech, balance problems;
• heart problems--swelling in your lower legs, rapid weight gain, feeling short of breath, cough, fast or pounding heartbeat, dizziness, feeling like you might pass out;
• liver problems--loss of appetite, stomach pain (upper right side), dark urine, jaundice (yellowing of the skin or eyes); or
• signs of tumor cell breakdown--confusion, weakness, muscle cramps, nausea, vomiting, fast or slow heart rate, decreased urination, tingling in your hands and feet or around your mouth.

Your cancer treatments may be delayed or permanently discontinued if you have certain side effects.

Common side effects may include:

• easy bruising or bleeding (especially nosebleeds);
• nausea, constipation;
• joint or muscle pain;
• headache; or
• feeling tired.

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.

Avoid activities that may increase your risk of bleeding or injury. Use extra care to prevent bleeding while shaving or brushing your teeth.