Ado-trastuzumab emtansine (Kadcyla™)

OncoLink Team
Last Modified: April 19, 2013

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

Classification: Monoclonal Antibody

About Kadcyla™

Kadcyla™ 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. Kadcyla™ 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 Kadcyla™

Kadcyla™ 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.

Possible Side Effects of Kadcyla™

There are a number of things you can do to manage the side effects of Kadcyla™. 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:

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.

Read the thrombocytopenia tip sheet for more information.

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. Read the anemia tip sheet for more information.

Allergic Reactions

In some cases, patients can have an allergic reaction to the 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 pre-medication or at a slower rate.

Nausea and/or Vomiting

Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms. Read the Nausea & Vomiting Tip Sheet for more suggestions.

Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


While on cancer treatment 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 and see OncoLink’s section on fatigue for helpful tips on dealing with this side effect.


There are several things you can do to prevent or relieve constipation. Include fiber in your diet (fruits and vegetables), drink 8-10 glasses of non-alcoholic fluids a day, and keep active. A stool softener once or twice a day may prevent constipation. If you do not have a bowel movement for 2-3 days, you should contact your healthcare team for suggestions to relieve the constipation.

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 drug. In some people, the symptoms slowly resolve after the drug 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 change the doses of your medication. See OncoLink's section on peripheral neuropathy for tips on dealing with this side effect.

Heart & Lung Toxicities

Kadcyla™ use can cause cardiac (heart) dysfunction, including severe heart failure (congestive heart failure). Patients should have their heart function tested with a "MUGA scan" prior to starting and regularly during therapy. If heart function decreases, Kadcyla™ should be stopped.

Kadcyla™ use can also result in toxicity to the lungs, including swelling, fluid and/or scarring within the lungs.

Symptoms to report to your healthcare provider include: new or worsening shortness of breath, cough, swelling in feet, ankles or legs, rapid weight gain or rapid heartbeat, as these can be symptoms of heart failure or lung toxicity.

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 your sperm are affected, you could still be fertile and conceive.

Other Side Effects

Kadcyla™ can affect your liver function. Your healthcare provider will monitor your liver function with blood tests regularly during your treatment. Symptoms to report to your healthcare provider include: nausea and vomiting, pain in the abdomen, jaundice (a yellowing of the skin or eyes) or dark tea-colored urine.

Other reported side effects include: muscle and joint pain, headache, and mouth sores.


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