Herceptin® (trastuzumab)
What is it?
Herceptin may be used to treat women whose breast cancer has come back or has spread to other parts of the body (secondary breast cancer). It may be given as a treatment on its own, or together with certain chemotherapy drugs. It is being used in trials to see whether it can reduce the chance of breast cancer returning, following initial treatment.
Before you take it
Herceptin works by interfering with one of the ways in which breast cancer cells divide and grow. At the moment, it seems that only a third of women with breast cancer have tumours that will be sensitive to Herceptin. Some breast cancer cells can be stimulated to divide and grow when a protein produced naturally in the body (human epidermal growth factor) attaches itself to another protein which is found on the surface of breast cancer cells (HER2, sometimes called CerbB2). Herceptin blocks this action by attaching itself to the HER2 protein so that the epidermal growth factor cannot reach the breast cancer cells. In doing so it 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 works best in women who have increased amounts of the HER2 protein and appears to have little effect in other women. At the moment, it is only used for women with high levels of HER2 protein. Several tests are available to measure this. Testing can be done at the same time as diagnosis, or samples of cancer cells from previous biopsies or surgery may be used. Herceptin on its own causes a shrinkage of the cancer in a minority of women, but research is assessing Herceptin's effects when it is given with certain chemotherapy drugs. If it is given with some chemotherapy drugs, particularly Taxol, it increases the effectiveness of the chemotherapy and may improve survival.
How to take it?
Herceptin is given by a drip into the vein (intravenously) through a fine tube (cannula) inserted into a vein. It can be given in the outpatient department at the hospital and the first dose is given slowly, usually over about an hour and half. After this, doses are given weekly and this normally takes about 30 minutes. Usually six doses are given. If it is given together with Taxol, this is given in the normal way, usually every three weeks.
Possible side effects
Because Herceptin works specifically on breast cancer cells and does not affect normal cells, the side effects appear to be mild. However, as it is still a relatively new drug it is too early to know all there is about possible side effects. The following appear to be the most common side effects:
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 drugs, which your doctor can prescribe for you.
Mild pain in parts of the body where the breast cancer has spread to. 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 persistent. 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.
Effects on the heart. When given with certain chemotherapy drugs, particularly doxorubicin (Adriamycin), it may lead to a proportion of people having heart problems. For that reason it is not recommended to be given with doxorubicin.
If you have any questions about these or any other side effects do talk to your doctor, pharmacist or nurse. It is also important to let them know if you are experiencing any symptoms or side effects that may be related to the treatment you are having.
Storing it
You will receive this medicine while you are in a hospital or chemotherapy treatment center. However it is important to know that diluted Herceptin has been shown to be stable for up to 24 hours at room temperature (2-25 degrees centigrade). However, since diluted Herceptin contains no effective preservative, the reconstituted and diluted solution should be stored refrigerated (2-8 degrees centigrade).
Futher information
For answers to specific healthcare questions or concerns, Roche recommends consulting your physician or professional healthcare provider.