Decorative image

Targeted cancer drugs

Find out about having targeted cancer drugs for breast cancer, including how you have them and the possible side effects.

Targeted cancer drugs are treatments that change the way cells work and help the body to control the growth of cancer.

When you might have targeted treatment

You might have targeted cancer treatment if your cancer cells have receptors for HER2 protein. Your doctors will test your cancer cells for these receptors. Around 15 out of every 100 breast cancers have them (15%). They are called HER2 positive cancers.

You might have a targeted drug called trastuzumab (Herceptin) before or after surgery and other treatments.

You might have a combination of trastuzumab and pertuzumab (Perjeta) before surgery if you have HER2 positive cancer that is one of the following:

  • early breast cancer that is at high risk of coming back
  • locally advanced breast cancer
  • inflammatory breast cancer

Trastuzumab (Herceptin)

Trastuzumab has the brand name Herceptin. It's a monoclonal antibody. Monoclonal antibodies attach to proteins on or in cancer cells.

Diagram showing a monoclonal antibody attached to a cancer cell

You have Herceptin every 3 weeks for a year. You normally have it into your bloodstream through a drip in your arm. Or you can have it as an injection under your skin.

You can't have trastuzumab if you have certain heart problems. You will have heart tests before you start treatment and every 3 months during treatment.

Pertuzumab (Perjeta)

Pertuzumab is a monoclonal antibody. You have it in combination with trastuzumab (Herceptin) and the chemotherapy drug docetaxel (Taxotere). You have it every 3 weeks into your bloodstream through a drip in your arm.

You have blood tests before each treatment.

Side effects

Possible side effects of targeted drugs for early breast cancer include:

  • an increased risk of infection
  • hot flushes and sweats
  • diarrhoea
  • joint or muscle pain
  • tiredness
  • an allergic reaction
Tell your doctor or nurse about any side effects that you have. They can help to reduce them.


Researchers are looking into new types of targeted cancer drugs for breast cancer. Some research is looking into using targeted drugs alongside chemotherapy to see how they work together.

You might have targeted cancer drugs other than trastuzumab as part of a clinical trial.

When you go home

Treatment with targeted drugs can be difficult to cope with for some people. Your nurse will give you a number to call (advice line) if you have any problems at home.

Contact your advice line if you have side effects or any concerns.

Information and help

Dangoor sponsorship

About Cancer generously supported by Dangoor Education since 2010.