What are targeted therapies?

Targeted therapies interfere with the way cancer cells grow.

The main targeted therapy drug used in breast cancer treatment is trastuzumab. It reduces the risk of breast cancer coming back in women with HER2 positive breast cancer.

It is also used in men with HER2 positive breast cancer.

Trastuzumab may be given with chemotherapy, or on its own. This can be before or after surgery and radiotherapy.

You may have trastuzumab in combination with another targeted therapy drug called pertuzumab (Perjeta®) and a chemotherapy drug. This combination may be used before surgery to treat HER2 positive breast cancer that has a high risk of coming back.

Trastuzumab and pertuzumab attach to the HER2 receptors on the surface of breast cancer cells and stop them from dividing and growing.


You usually have trastuzumab every 3 weeks for 1 year. It is given in the chemotherapy day unit or outpatient department.

You have trastuzumab in one of the following ways:

  • As a drip (infusion) into a vein

    A nurse gives the first dose slowly, usually over 90 minutes. This is because some people can have a reaction. The nurses monitor you during the drip and for about 4 to 6 hours afterwards. If you have no problems, you have the next doses over 30 to 60 minutes. You can also go home soon after the treatment is finished.

  • As an injection under the skin (subcutaneously)

    A nurse gives you the injection into your thigh. This only takes a few minutes. You are monitored for a few hours after the first injection. This is to make sure you do not have a reaction. But after the next injections, you will be monitored for a much shorter time.


Pertuzumab is given every 3 weeks. It is given as a drip into a vein. The first dose is usually given slowly over about 60 minutes. This is because some people can have a reaction.

The nurses monitor you during the drip and for about 60 minutes afterwards. If you have no problems, you can have the next doses over 30 to 60 minutes.

About our information

  • References

    Below is a sample of the sources used in our breast cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    European Society for Medical Oncology. Primary breast cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of oncology 26 (supplement 5): v8–v30. 2015.

    Morrow M, et al. Chapter 79: malignant tumors of the breast. DeVita, Hellman and Rosenberg’s cancer: principals and practice of oncology (10th edition). Lippincott Williams and Wilkins. 2014.

    National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management. July 2018.

    Scottish Intercollegiate Guidelines Network. SIGN 134. Treatment of primary breast cancer: a national clinical guideline. September 2013.

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Rebecca Roylance, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.