Ado-trastuzumab Emtansine (Kadcyla®)

OncoLink Team
Last Modified: July 20, 2015

Pronounced: A-doh-tras-TOO-zoo-mab em-TAN-seen

Classification: monoclonal antibody

About Ado-trastuzumab Emtansine (Kadcyla®)

Ado-trastuzumab emtansine is a monoclonal antibody attached to a chemotherapy agent called maytansine (a microtubule inhibitor). Monoclonal antibodies are designed to target a specific type of cell – in this case, a Her2- positive breast cancer cell. Her2 is a protein that is overexpressed in about 25-30% of all breast cancers. Her2 receptors on cells send signals telling the cell to grow and divide. Cancers that overexpress Her2 have too many receptors, which cause the cells to grow and divide more quickly. Ado-trastuzumab emtansine attaches itself to the Her2 receptor and pushes the chemotherapy into the cell – think of it as a smart bomb that targets the cancer cells with chemotherapy.

How to Take Ado-trastuzumab Emtansine (Kadcyla®)

Ado-trastuzumab emtansine is given by IV (into a vein) infusion, typically once every 3 weeks. The initial infusion generally takes about 90 minutes, and subsequent treatments may take 30-90 minutes, depending on how you tolerate the infusion. The actual dose is based on your body size and type of cancer.

Even when carefully and correctly administered by trained personnel, this drug may cause a feeling of burning and pain. There is a risk that this drug may leak out of the vein at the injection site, resulting in tissue damage that can be severe. If the area of injection becomes red, swollen, or painful at anytime during or after the injection, notify your doctor or nurse immediately. Do not apply anything to the site unless instructed by your doctor or nurse.

Possible Side Effects of Ado-trastuzumab Emtansine (Kadcyla®)

There are a number of things you can do to manage the side effects of ado-trastuzumab emtansine. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Infusion reactions

In some cases, patients can have an allergic reaction to this medication. Signs of a reaction can include: shortness of breath or difficulty breathing, chest pain, rash, flushing or itching or a decrease in blood pressure. If you notice any changes in how you feel during the infusion, let your nurse know immediately. The infusion will be slowed or stopped if this occurs. Depending on the severity of your reaction, you may still be able to receive the medication with a pre-medication to prevent a reaction, or if the medication is given at a slower rate.

Low Platelet Count (Thrombocytopenia)

Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your doctor or nurse know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.

  • Do not use a razor (an electric razor is fine).
  • Avoid contact sports and activities that can result in injury or bleeding.
  • Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin®, Aleve®, Advil®, etc. as these can all increase the risk of bleeding. Unless your healthcare team tells you otherwise, you may take acetaminophen (Tylenol).
  • Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.

Heart Problems

This medication can cause cardiac (heart) problems including reduced heart function and congestive heart failure.  Your care team will monitor your cardiac functioning.  If you have symptoms including rapid weight gain, swelling in the legs and ankles, shortness of breath or irregular heart beat contact your health care provider immediately or go to the emergency room.

Liver Toxicity

This medication can cause liver toxicity, which your doctor may monitor for using blood tests called liver function tests. If you develop elevations in your liver function tests, your healthcare provider may need to lower your dose or stop the medication. Notify your healthcare provider if you notice yellowing of the skin or eyes, your urine appears dark or brown or pain in your abdomen, as these can be signs of liver toxicity.

Lung Problems

This medication may cause lung problems, including inflammation of the lung tissue. Signs of lung problems may include trouble breathing, cough, tiredness, and fluid in the lungs.  If you experience any of these symptoms, contact your healthcare provider or go to the emergency room.

Low Red Blood Cell Count (Anemia)

Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your doctor or nurse know if you experience any shortness of breath, difficulty breathing or pain in your chest. If the count gets too low, you may receive a blood transfusion.

Peripheral Neuropathy (Numbness or Tingling in the Hands and/or Feet)

Peripheral neuropathy is a toxicity that affects the nerves. It causes a numbness or tingling feeling in the hands and feet, often in the pattern of a stocking or glove. This can get progressively worse with additional doses of the medication. In some people, the symptoms slowly resolve after the medication is stopped, but for some it never goes away completely. You should let your healthcare provider know if you experience numbness or tingling in the hands and feet, as they may need to adjust the doses of your medication.


Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect.

Low potassium (hypokalemia)

Hypokalemia is an electrolyte imbalance which is indicated by a low level of potassium in the blood.  This medication can cause hypokalemia. Your oncology team will periodically check your blood potassium levels while receiving this medication.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment and for at least 6 months after treatment. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. You should consult with your healthcare team before breastfeeding while receiving this medication.



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