The medicineinfo-icon trastuzumabinfo-icon (Herceptininfo-icon) is the most common medicine used to treat HER2- positive breast cancer. It is a monoclonal antibodyinfo-icon, a medicine made in a lab that attacks a specific proteininfo-icon produced on the outside of a cellinfo-icon. It falls in a class of medicines called targeted therapies.

Research shows people with HER2-positive breast cancer treated with trastuzumab along with chemotherapyinfo-icon are likely to live longer than those with HER2-positive disease who receive chemotherapy alone. Treatment with trastuzumab and chemotherapy also cuts the risk of recurrenceinfo-icon, or return of the cancer, in half.

How Trastuzumab Works

Trastuzumabinfo-icon works by attaching to HER2 proteins and blocking the signals that tell cells to multiply too quickly, causing cancer.

How Trastuzumab Is Given

In early-stageinfo-icon disease, you may receive trastuzumabinfo-icon either before or after surgeryinfo-icon. The medicineinfo-icon is given by veininfo-icon, either once a week or once every 3 weeks for one year. It is almost always given with chemotherapyinfo-icon. If you have a high risk of recurrenceinfo-icon, you may also receive  pertuzumab (Perjeta), another HER2-targeting treatment, either before or after surgery. Common combinations that include trastuzumab are:

One common plan is to take chemotherapy alone for several cycles, and then take taxane chemotherapy along with trastuzumab. When you finish the taxaneinfo-icon, your team will continue to give you trastuzumab until you finish about a year of treatment. Your providers may also give you all your chemotherapy first and then start trastuzumab. Ask why they suggest one option over the other.

When given before surgery, trastuzumab and medicines given with it help to shrink large tumors. In some cases, this neoadjuvant treatment makes it possible to have a lumpectomyinfo-icon instead of a mastectomyinfo-icon.

In metastaticinfo-icon breast cancer, trastuzumab can be given alone on an ongoing basis or with pertuzumabinfo-icon and chemotherapy. Ask your team to explain why they recommend a certain treatment or combination.

You and your doctor will discuss the best treatments for your situation.

Side Effects and Things to Remember

In general, trastuzumabinfo-icon is less likely than chemotherapyinfo-icon to cause serious side effects that could make you need to stop treatment. Some people have flu-like symptoms after starting trastuzumab. The most common side effects include

If you are also receiving chemotherapy, you may also have chemotherapy side effects.

Heart problems are a rare but serious possible side effectinfo-icon of trastuzumab. The idea of heart issues can be scary, but research shows most heart problems caused by trastuzumab are not permanent or long-term. Though it’s unlikely you’ll have serious heart problems while taking trastuzumab, it’s important your doctor closely monitor your heart health while you take this medicineinfo-icon.

Before you start trastuzumab and throughout treatment, you should get echocardiograms (sometimes called echos), tests that look at your heart health. If your first echo suggests you have heart problems, trastuzumab may not be the right treatment for you. Talk with your healthcare team about other options.

Before starting trastuzumab, tell your doctor about any medicines you are taking, including vitamins, herbal supplements and over-the-counterinfo-icon medicines. You should not become pregnant while taking trastuzumab.

Your doctor, pharmacistinfo-icon or nurseinfo-icon can help you manage your side effects. You can also go to our section on Side Effects for more information.

March 15, 2018