Targeted (biological) therapies for breast cancer

What are targeted therapies?

Targeted therapies (sometimes called biological therapies) are new drugs that work differently from chemotherapy. The main targeted therapy used in breast cancer treatment is trastuzumab (usually called Herceptin®). It reduces the risk of breast cancer coming back in women with HER2 positive breast cancer.

Trastuzumab attaches to the HER2 receptors on the surface of breast cancer cells and stops them from dividing and growing. You will usually have trastuzumab every three weeks for a year. It is given with chemotherapy, or on its own.

How trastuzumab is given

Trastuzumab can be given as a drip (infusion) into a vein (intravenously) or as an injection under the skin (subcutaneously).

When it’s given as a drip, you have it slowly the first time (over an hour and a half) and the nurse will check you for signs of a reaction. You can then have future infusions over about 30 minutes.

It only takes a few minutes to have it as an injection under the skin. But you will still need to wait for an hour and a half so the nurse can check you for any reaction.

Side effects

The side effects of trastuzumab are usually mild. You may have some while having the drip or up to four hours after, particularly with the first dose. These include flu-like symptoms such as a:

  • headache
  • high temperature (fever) and chills
  • feeling sick. 

They generally get better within a few hours of the drip finishing. Another possible side effect is an allergic reaction, but this is rare. The nurses will check for signs of a reaction. If it happens, they can treat it quickly with drugs.

You may get other side effects after treatment. These include diarrhoea, headaches and feeling sick.

Effects on the heart

Trastuzumab may lead to changes in the way your heart works and can cause problems in some women. Usually, any effect is mild and reversible. You may be given heart medicines to help with this side effect.

You will have tests to check your heart before and during treatment to make sure the drug isn’t causing any damage. Trastuzumab isn’t usually given to women who already have heart problems.