Trastuzumab (Herceptin®)
This information is about the use of trastuzumab (pronounced tras-to-zoo-mab) as a treatment for people with cancer. It is commonly known as Herceptin®. It is used to treat women with breast cancer. It should ideally be read with our general information about breast cancer and secondary breast cancer, or about your type of cancer.
- What is Herceptin?
- How it works
- How it is given
- When it may be given
- Possible side effects
How it works
Herceptin works by interfering with one of the ways in which breast cancer cells divide and grow. Some breast cancer cells divide and grow when a protein that naturally occurs in the body (known as human epidermal growth factor) attaches itself to another protein known as HER2, which is found on the surface of some breast cancer cells.
Herceptin blocks this process by attaching itself to the HER2 protein so that the epidermal growth factor cannot reach the breast cancer cells. This stops the cells from dividing and growing. Herceptin also works by attracting the body’s own immune cells to help destroy the cancer cells.
Herceptin only works in people who have high levels of the HER2 protein. It appears to have little effect in those who do not. At the moment it seems that only about one in five women with breast cancer have tumours that will be sensitive to Herceptin. It is thought that fewer men with breast cancer have tumours that are sensitive.
Several tests are available to measure HER2 levels. Testing can be done at the same time as initial breast cancer surgery, or samples of cancer cells from previous biopsies or surgery may be used.
Current research is assessing Herceptin's effects when it is given with certain chemotherapy drugs. If it is given with some chemotherapy drugs, particularly paclitaxel (Taxol) and docetaxel (Taxotere®), it increases the effectiveness of the chemotherapy and may improve survival. Herceptin on its own causes a shrinkage of the cancer in a few women and stops it growing in others.
How it is given
Herceptin is given by a drip (infusion) through a fine tube (cannula) inserted into a vein. It can usually be given in the outpatient department at the hospital.
The first dose is given slowly, usually over about an hour and a half. After this, doses normally take about 30 minutes. After the infusion you will need to stay for a short time to make sure that you don't have a reaction to the Herceptin. The drug may be given once a week or once every three weeks. If Herceptin is given together with Taxol or Taxotere, they are given in the normal way, which is usually every three weeks.
When it may be given
In the UK, Herceptin is used mainly to treat women with breast cancer. It may be used in the early stages to increase the chances of a cure or in advanced stages to help control the disease when the breast cancer has come back.
Some other cancers also have high levels of the HER2 protein and research trials are currently underway to see if Herceptin may help in conditions other than breast cancer.
Possible side effects
Each person's reaction to a cancer drug is different. Some people have very few side effects, while others may experience more. We have outlined the most common side effects. We have not included those that are rare, however, and which are therefore extremely unlikely to affect you. If you notice any effects that you think may be due to the drug, but which are not listed below, please discuss them with your doctor or nurse.
The side effects appear to be mild because Herceptin works specifically on breast cancer cells and does not affect normal cells.
Effects on the heart Herceptin may lead to some people having heart problems. For that reason it is recommended that Herceptin is not given to people with a history of heart disease or high blood pressure.
In order to check your normal heart function, you will have tests (usually an echocardiogram) before starting treatment with Herceptin.
Flu-like symptoms This includes a high temperature (fever) and chills, shortly after the drug is given. These symptoms can be controlled or reduced with medicines, which your doctor can prescribe for you.
Tumour pain Some people may experience mild pain in parts of the body to which the breast cancer has spread. Painkillers can be given to relieve this.
Diarrhoea This can usually be controlled with medicine, but let your doctor know if it is severe or if it continues. It is important to drink plenty of fluids if you have diarrhoea.
Headaches Let your doctor know if you have headaches while having treatment with Herceptin.
Allergic reactions This is a rare side effect of Herceptin. Signs of this include skin rashes and itching, wheezing, difficulty breathing, and breathlessness. You will be closely monitored during your treatment, but let your nurse or doctor know if you have any of these symptoms. To reduce the chance of developing an allergic reaction, antihistamines can be given before the infusion. The infusion can also be slowed down or stopped until the reaction is over.
If you have any questions about these or any other side effects, talk to your doctor or nurse.
If Herceptin is given in combination with chemotherapy you will also experience the side effects of the chemotherapy drug.
