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Ado-trastuzumab emtansine

(add-oh traz-too-zuh-mab em-tan-seen)

Trade/other name(s): Kadcyla, trastuzumab emtansine, T-DM1

Why would this drug be used?

This drug is used to treat certain types of breast cancer. It is being studied for use against other types of cancer as well.

How does this drug work?

Ado-trastuzumab emtansine is a type of drug known as an antibody-drug conjugate. It has 2 parts. The first is a monoclonal antibody (a man-made version of an immune system protein) called trastuzumab. It specifically attaches to the HER2 protein, which is found on the surface of cells and normally helps them grow. Some breast (and other) cancers have higher than normal amount of this protein on their cells. The second part is a chemotherapy drug known as DM1, which works by interfering with microtubules, part of the internal scaffolding needed by cells when they are dividing to make new cells.

The antibody acts like a homing signal, bringing the chemotherapy drug to the cancer cells, where it enters the cells and causes them to die when they try to divide. The antibody itself may also help to stop the cancer cells from growing and may cause the body’s immune system to help kill them.

Not all breast cancers have too much of the HER2 protein on the cell surfaces. Your doctor will test your cancer cells to be sure they have this before starting treatment with this drug. (Most likely this will already have been done before you received other treatments aimed at HER2.)

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have ever had heart problems (such as congestive heart failure, an abnormal heart rhythm, or a recent heart attack), radiation to the chest, or if you have ever had medicines that might have damaged your heart. This drug may raise your risk of heart failure (see “Precautions” below).
  • If you have any type of liver disease, including hepatitis or cirrhosis. This drug can damage the liver, which in some cases might even be life threatening (see “Precautions” below).
  • If you have any other medical conditions such as kidney disease, diabetes, gout, or infections. Your doctor may need to monitor you more closely during treatment.
  • If you had to stop getting trastuzumab (Herceptin), a similar drug, because you had a reaction to it. People who have had serious reactions to trastuzumab should not get this drug.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug can cause harm to the fetus if it is given to a woman during pregnancy Women who could become pregnant need to follow special precautions if taking this drug (see “Precautions” below).
  • If you are breast-feeding. While no studies have been done, this drug may pass into breast milk and affect the baby. Women should not breast-feed during treatment with this drug (see “Precautions” below).
  • If you think you might want to have children in the future. This drug has not been tested for its effects on fertility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

This drug might interact with a number of other drugs and supplements, so it is important to check with your health care team before taking any new medicines.

Some drugs could cause this drug to build up in your blood, which might worsen side effects and other problems:

  • Some antibiotics, such as erythromycin, clarithromycin (Biaxin), telithromycin (Ketek), and similar drugs
  • Anti-fungal medicines such as ketoconazole (Nizoral), itraconazole (Sporanox), and voriconazole (Vfend)
  • Some anti-depressant drugs, such as nefazodone (Serzone)
  • Some anti-HIV drugs, such as indinavir (Crixivan), ritonavir (Kaletra), nelfinavir (Viracept), atazanavir (Reyataz), saquinavir (Invirase), and others

These drugs should be avoided while taking ado-trastuzumab emtansine if possible. If you need to take any of them, your dose of this drug may need to be delayed.

Some drugs and supplements might lower the levels of this drug in the blood, which might make it less effective:

  • Anti-seizure drugs, such as carbamazepine (Tegretol), phenobarbital (Solfoton), and phenytoin (Dilantin)
  • Drugs to treat tuberculosis (TB), such as rifampin (Rifadin, Rimactane; also in Rifamate and Rifater), rifabutin (Mycobutin), and rifapentin (Prifin)
  • The steroid drug dexamethasone (Decadron)
  • St. John’s wort (herbal dietary supplement)

Do not start or stop taking any of these medicines without talking with your doctor(s) about all of the medicines you take.

This drug can increase your risk of uncontrolled bleeding (see “Precautions”). Drugs and supplements that interfere with blood clotting can increase this risk further. These include:

  • Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn) and many others
  • Vitamin E
  • Warfarin (Coumadin)
  • Ticlopidine (Ticlid)
  • Clopidogrel (Plavix)
  • Dabigatran (Pradaxa)
  • Rivaroxaban (Xarelto)
  • Apixaban (Eliquis)
  • Fondaparinux (Arixtra)
  • Any type of heparin including enoxaparin (Lovenox) and dalteparin (Fragmin)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren’t sure what’s in the medicines you take.

No other serious interactions are known at this time, but this does not necessarily mean that none exist. Check with your doctor, nurse, or pharmacist about your other medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

Grapefruit, grapefruit juice, or grapefruit extract might change the level of this drug in your blood. Check with your doctor, nurse, or pharmacist about whether you should avoid grapefruit products during treatment with this drug, and about whether other foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

This drug is given by infusion in a vein (IV). The dose depends on your weight.

The first dose is typically given over 90 minutes. You will be watched closely during the first infusion and for at least 90 minutes afterward for possible signs of an infusion reaction (see “Precautions” below). If you don’t have any problems, later doses can be given over 30 minutes, after which you will be watched closely for another 30 minutes. Your doctor or nurse might give you medicine before your treatment to try to prevent an infusion reaction.

This drug is typically given once every 3 weeks. Later treatments might need to be delayed and/or the dose reduced if you have a reaction during the infusion or have other side effects. If the effects are severe enough, treatment with this drug might need to be stopped altogether.


This drug can cause infusion reactions in some people when it is given, especially with the first treatment. Mild reactions usually consist of fever and chills. More serious reactions happen rarely, but can be dangerous. Symptoms can include flushing (warmth and redness of the skin), feeling lightheaded or dizzy (due to low blood pressure), fast heartbeat, hives, nausea, itching, headache, coughing, tightness in the throat or chest, shortness of breath, or swelling of the face, tongue, or eyes. Tell your doctor or nurse right away if you notice any of these symptoms during or after being given the drug.

This drug can damage the liver, which in some cases might be life threatening. Your doctor will check your liver function with blood tests before each treatment with this drug. Your dose may need to be lowered and/or delayed, or the drug stopped altogether if the tests show liver damage. Tell your doctor right away if you notice possible symptoms of liver damage, such as nausea, vomiting, pain in the abdomen (especially on the right side), yellowing of the skin or eyes (jaundice), dark urine, loss of appetite, or itching skin.

This drug may damage the muscle of the heart. This risk is higher if you are also treated with other drugs that can damage the heart, such as chemotherapy drugs known as anthracyclines (including doxorubicin and epirubicin). Your doctor will test your heart function before treatment and regularly (about every 3 months) during treatment with this drug. Possible symptoms of heart damage might include increased coughing, trouble breathing (especially at night), heart palpitations, rapid weight gain (5 pounds or more in less than a week – for a reliable weight, be sure to weigh yourself at the same time of day while wearing the same type of clothes), dizziness, fainting, or swelling in the ankles or legs. Tell your doctor right away if you start to notice any of these symptoms once treatment starts.

In rare cases, patients have developed severe lung disease (pneumonitis) during treatment with this drug. Tell your doctor right away if you have symptoms that might be caused by lung problems, such as trouble breathing, coughing, wheezing, or feeling tired.

This drug might cause nerve damage (neuropathy). This can lead to numbness, weakness, pain, or sensations of burning or tingling, usually in the hands or feet. These symptoms can sometimes progress to include sensitivity to cold or trouble walking or holding things in your hands. Let your doctor know right away if you notice any of these problems. If your symptoms are severe enough, this drug may need to be stopped or the dose reduced until they get better.

This drug might leak from the vein or needle and cause reactions such as redness, tenderness, skin irritation, or pain or swelling at the infusion site. If this happens, it is likely to be within 24 hours of the infusion. Tell your doctor or nurse right away if you notice any of these symptoms.

Your doctor will test your blood throughout your treatment, looking for possible effects of the drug on blood cell counts or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it altogether. Keep all your appointments for lab tests and doctor visits.

This drug can lower your blood platelet count, which can raise your risk of bleeding. Your doctor will check your platelet count before each treatment, and your dose might need to be delayed and/or reduced if you have a low platelet count. Be sure your doctor knows if you take any medicines that may affect your body’s ability to stop bleeding (see “Interactions with other drugs”), because these can increase the risk of serious bleeding.

This drug can increase your risk of serious bleeding. The risk may be higher if your platelet count is low or if you are taking certain medicines such as blood thinners (see “Interactions with other drugs”), but bleeding has can happen without these risk factors. Tell your doctor right away if you cough up blood or have unusual bruising, nosebleeds, unexpected or severe vaginal bleeding, bleeding gums when you brush your teeth, vomit that is bloody or looks like coffee grounds, or black, tarry stools. Bleeding that happens in the brain can cause symptoms of a stroke, such as weakness and/or numbness on one side of the body, and trouble speaking or moving. If you have these symptoms get emergency help.

This drug might lower your red blood cell count. If this occurs, it will usually happen a few months after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you to feel weak or tired all the time.

This drug can lower your white blood cell count. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, new onset of cough, or bringing up sputum.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor’s OK. This drug might affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get live vaccines during treatment or for some time afterward. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

This drug should not be taken if you are pregnant. This drug might cause problems with the fetus if taken at the time of conception or during pregnancy. Women who could become pregnant need to use effective birth control during treatment and for at least 6 months afterward. Check with your doctor about what kinds of birth control can be used with this medicine. Tell your doctor right away if you think you might be pregnant.

This drug might pass into breast milk, which could affect the baby. This drug should not be taken if you are breast-feeding. Women who are taking this drug and their doctors should decide if they will get this drug or breast-feed, but they should not do both.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • Nausea
  • Feeling tired
  • Muscle, bone, or joint pain
  • Headache
  • Low blood platelet count (with increased risk of bleeding)*
  • Abnormal results on blood tests of liver function (your doctor will discuss what these mean)*
  • Constipation
  • Diarrhea
  • Bleeding, including nosebleeds
  • Numbness or tingling in the hands or feet*

Less common

  • Vomiting
  • Cough
  • Pain in the abdomen
  • Fever
  • Feeling weak
  • Dry mouth
  • Swelling or sores in the mouth
  • Low red blood cell count (anemia)*
  • Trouble sleeping
  • Rash or itchy skin
  • Shortness of breath
  • Feeling dizzy
  • Upset stomach
  • Urinary tract infection
  • Abnormal levels of certain minerals on blood tests (your doctor will discuss what these mean)
  • Change in how things taste
  • Chills
  • Swelling in the hands or feet
  • High blood pressure
  • Low white blood cell count (with increased risk of infection)*


  • Too many or too few tears, blurred vision, or conjunctivitis (pink eye)
  • Serious bleeding, which can happen in the brain (stroke), lungs, stomach, or intestines*
  • Drug leaking out of vein, causing redness or irritation at infusion site*
  • Reaction during or shortly after infusion*
  • Damage to the heart muscle*
  • Damage to the liver*
  • Damage to the lungs*
  • Death due to heart damage, liver damage, lung disease, bleeding, or other cause

*See the “Precautions” section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2013

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 09/16/2014
Last Revised: 09/16/2014