Herceptin^® Frequently Asked Questions

1. What is Herceptin^®?

Herceptin® is a monoclonal antibody that blocks the effects of the growth factor protein HER2 which transmits growth signals to breast cancer cells. Some breast cancers have too much of this protein (HER2 positive cancers), which can cause the cancer to grow and spread more quickly. Herceptin® can help stop this growth.

Herceptin®, also known as Trastuzumab, is only used to treat HER2 positive breast cancer. It is a white to pale yellow powder which is dissolved into a clear, colourless liquid and is administered intravenously either once a week or once every three weeks. It can be used either as a stand alone treatment or in conjunction with other chemotherapy.

For several years, Herceptin has been an established part of treatment for patients with advanced HER2 positive cancer that has spread throughout the body. Adding Herceptin to chemotherapy increases the length of time until the cancer progresses again and increases the duration of life. Recent studies have shown that Herceptin is also beneficial in patients with early stage HER2 positive cancer, where the cancer is limited to the breast and underarm lymph nodes. Treatment of patients with early breast cancer aims not only to extend life, as in advanced cancer, but to cure the disease. International trials involving over 12,000 women with early-stage HER2-positive breast cancer show that Herceptin given with or after post-operative chemotherapy reduced the risk of the cancer recurring by up to half, compared with chemotherapy alone. After 2-3 years, around one third more patients who had received 1 year of Herceptin treatment were alive and were free of disease among those than those who had not.

2. What is HER2?

Human Epidermal growth factor Receptor 2 (HER2) is a member of a family of growth factor receptors that are important for controlling cell growth. HER2 is present in small amounts in normal breast cells and breast cancer. However, if a breast cancer has either too many HER2 genes, (HER2 gene amplification) or produces large amounts of HER2 protein (HER2 protein over expression) then it is called HER2 positive. About 25% of all breast cancers are HER2 positive and these cancers tend to occur in younger patients, grow quickly, spread rapidly, and have a higher rate of recurrence. Following surgery and standard chemotherapy, on average across all types of breast cancer, 80% of women will be alive 10 years after diagnosis. In comparison, only 50% of women with HER2-positive breast cancer will be alive 10 years after diagnosis. The chance of survival for an individual patient depends on the stage of the disease at diagnosis and the treatments provided.

3. Should I know my HER2 status?

Yes. Knowing whether you do have HER2 positive breast cancer will impact on the treatment options available to you. It is important that your doctor discusses these options with you to ensure that you make the best informed decision regarding your breast cancer treatment. A HER2 test should now be performed routinely on all newly diagnosed breast cancer or a new breast cancer recurrence. Don’t be afraid to ask for your HER2 result and request the test if it has not been done.

4. What is a HER2 test?

Breast cancer tissue removed from the body during a biopsy or surgery is sliced and stained using the immunohistochemistry (IHC) test which measures the HER2 protein levels using a scale from 0 through 1+, 2+ to 3+. If a breast cancer is scored as 0 or 1+, it is considered negative and people in that category do not benefit from Herceptin®. Women whose breast cancer is scored as 3+ are the most likely to benefit from Herceptin®. Women whose cancer is scored as 2+ may or may not benefit from Herceptin®. The best way to find out is to further test the tumour sample with the FISH test. So if your cancer is 2+, your doctor will ask for the FISH test to be done.

5. What is the FISH test?

The Fluorescence In Situ Hybridization (FISH) test illuminates the HER2 genes in the tumour sample to see how many there are. If a FISH test detects more than 2 copies of the HER2 gene, this means that the cell is abnormal and the breast cancer is called “FISH positive” which also means the cancer is now called “HER2 positive”. These women are also more likely to benefit from Herceptin®. If “FISH negative”, then the women will not benefit from Herceptin®.

6. How does Herceptin^® work?

In three different ways:

First, it binds to the HER2 proteins on the surface of the tumour cell and blocks signals for cell growth. This may result in cancer cell death.

Second, when Herceptin® binds to the HER2 proteins on the surface of the tumour cell, immune system cells within the body recognise it as a foreign object and attack, helping to more effectively kill the cancer cells.

Third, Herceptin® and chemotherapies can form a very effective team. Herceptin® can enhance the effectiveness of chemotherapy which attacks and damages the DNA in the nuclei of tumour cells and causes cancer cell death.

7. What are the possible risks of using Herceptin^®?

Compared with chemotherapy drugs, the side effects of Herceptin® are relatively mild. They may include fever and chills, weakness, nausea, vomiting, cough, diarrhoea, and headache. These side effects are usually associated with the first dose and not seen again. Some women being treated with Herceptin®, however, have experienced heart damage leading to a problem called congestive heart failure. For most women, this effect on the heart has been temporary and has improved when the drug is stopped. The risk of heart problems is about 3 times higher when Herceptin® is given with anthracyclines, a class of chemotherapy drugs that includes doxorubicin (Adriamycin) and epirubicin (Ellence) and may not be reversible. Major symptoms are shortness of breath and severe fatigue. Women experiencing these symptoms should call their doctor right away.

8. What are the benefits of using Herceptin^®?

Recent study results have indicated that administration of Herceptin® following standard chemotherapy significantly reduces the risk of recurrence for women with early-stage HER2 positive breast cancer by 36-46% with a 34% overall survival benefit after an average of 23 months follow-up. Increased spending on cancer drugs may actually save money in other areas of health by treating patients more effectively and earlier, thereforepreventing recurrence and advancement of cancer. This not only eliminates unnecessary worry and suffering by patients but also makes economic sense because people can return to being productive members of their families, their workplace and our society.

Trials involving women with advanced breast cancer also confirmed the benefits of Herceptin®. A recent study showed that 3 years after treatment, twice as many women with HER2 positive advanced breast cancer who received Herceptin® and chemotherapy were alive than those who were treated with chemotherapy alone.

9. How much does Herceptin^® cost?

Herceptin® is not currently government funded for women with early-stage HER2 positive breast cancer but PHARMAC is currently reviewing this. In the meantime, it costs approximately $60,000 to $100,000 per patient. For women with advanced breast cancer which is HER2 3+ or FISH+, Herceptin® is already government funded in New Zealand.

10. What is the duration of treatment with Herceptin®?

This depends on a person’s response to treatment and/or the state of the breast cancer. Standard Herceptin treatment duration for HER2 positive early breast cancer is 12 months.

Source: Breast Cancer Aotearoa Coalition (BCAC) and the Infotorial by ADIS, entitled: "Fact Sheet: Herceptin in the Treatment of Early Aggressive Breast Cancer" (dated 5 February 2007).

Other Herceptin® information:
Herceptin® in Early Stage Breast Cancer - a Story in Progress
Breast Cancer Network submission to Pharmac June 2008
BCAC submission to Pharmac June 2008