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What is Trastuzumab Emtansine

31st July 2022 by Claire O'Donnell Education

Trastuzumab Emtansine

What is Trastuzumab Emtansine

Trastuzumab emtansine is a type of targeted cancer drug. It is also known by its brand name Kadcyla and TDM1.

It is a treatment for breast cancer that has spread or come back within 6 months of finishing treatment (advanced breast cancer) 

Trastuzumab emtansine is a combination of the drug trastuzumab (also known by its brand name Herceptin) and a drug called emtansine. It is for HER2 positive breast cancer.


How trastuzumab emtansine works

Trastuzumab is a type of targeted cancer drug (biological therapy) called monoclonal antibody. Emtansine is a cancer drug that becomes active once it enters the cancer cell.

Some breast cancers have too much of a protein called human epidermal growth factor receptor 2 (HER2) on the surface of their cells. These are called HER2 positive cancers. HER2 makes the cells grow and divide. Trastuzumab attaches to the HER2 receptor. When this happens it allows the emtansine to go into the cancer cell. Inside the cell emtansine becomes active and kills the cancer cell.


How you have trastuzumab emtansine

You have trastuzumab emtansine as a drip into your bloodstream (intravenously).

You have treatment through a cannula or you might have treatment through a long line: a central line, a PICC line or a portacath. 


When you have trastuzumab emtansine

You have trastuzumab emtansine once every 3 weeks, this is one cycle of treatment. You have the first treatment over 90 minutes. You usually have your first treatment as an inpatient to monitor you for any reactions to the drug. If the first one went well you might have the next treatments over 30 minutes. 

For breast cancer that has come back or spread around the body, you continue to have treatment for as long as it helps and the side effects aren't too bad.

If you're having radiotherapy as well as trastuzumab emtansine your treatment is usually spaced to reduce the risk of having radiation related side effects. 



You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

You usually have heart tests such as an echocardiogram (ECHO) or a multigated acquisition (MUGA) scan to build up a picture of how well your heart if working. You usually have one of these before starting treatment and every 3 months during treatment. 


Common Side Effects:

  • Liver change

  • Bruising, bleeding gums or nose bleeds

  • Numbness or tingling in fingers or toes

  • Breathlessness and looking pale

  • Feeling or being sick

  • Diarrhoea or constipation

  • Dry mouth

  • Urinary tract infections (UTIs)

  • Difficulty sleeping

  • Headaches

  • Tummy (abdominal) cramps

  • Cough and difficulty breathing

  • Sore mouth

  • Joint or muscle pain

  • Tiredness and weakness

  • High temperature (fever)