Targeted therapy for secondary breast cancer

Targeted therapies interfere with the way cells grow and divide. Targeted therapy drugs may be used with chemotherapy or hormonal therapy drugs for secondary breast cancer.

What are targeted therapies?

Targeted therapy drugs interfere with the way cancer cells signal or interact with each other. This stops them growing and dividing.

For secondary breast cancer you usually have targeted therapy drugs with chemotherapy or hormonal therapy drugs. Your doctor will explain which targeted therapy drug or drugs are suitable for you. This depends on whether the cancer cells have receptors for the HER2 protein or for the hormone oestrogen. We have more about receptors in our information about secondary breast cancer.

Palbociclib and ribociclib

If the secondary cancer is HER2 negative and ER positive, your doctor may advise having either of these drugs along with hormonal therapy.

Palbociclib (Ibrance®) and ribociclib (Kisqali®) are taken as tablets, usually for 3 weeks at a time. You then have a week off before starting them again.


Trastuzumab is the main targeted therapy drug used to treat HER2 positive secondary breast cancer. It was previously called Herceptin®.

Trastuzumab can be given:

You will have trastuzumab in one of the following ways:

  • As a drip (infusion) into a vein every 3 weeks
  • As a small injection under the skin.



Pertuzumab (Perjeta®) is another targeted therapy drug that works in a similar way to trastuzumab. It is usually given with trastuzumab and the chemotherapy drug docetaxel. If you have not had a targeted therapy drug or chemotherapy before, you may have this as your first treatment.

You will have pertuzumab into a vein (intravenously) as a drip (infusion) every 3 weeks.

We have more information about pertuzumab, trastuzumab and docetaxel given together.

Trastuzumab emtansine

Trastuzumab emtansine (Kadcyla®) is trastuzumab with the chemotherapy drug emtansine attached to it. Trastuzumab targets and delivers the chemotherapy to the cancer cells. It may be given after you have already had treatment with trastuzumab, docetaxel or paclitaxel, either separately or together.

You will have trastuzumab emtansine into a vein (intravenously) as a drip (infusion) every 3 weeks.


Everolimus is a targeted therapy drug that may be given if the cancer is HER2 negative and ER positive with the hormonal drug exemestane. You need to have already had treatment with other hormonal therapy drugs before you can take it.

You take everolimus as a tablet once a day.


If the secondary breast cancer does not have receptors for HER2 or for hormones it is called triple negative breast cancer. A drug such as olaparib (Lynparza®) may be used but usually a clinical trial.

Olaparib blocks how PARP proteins work in cancer cells that have a change (mutation) in the BRCA1 or BRCA2 gene. These gene mutations are more common in triple negative breast cancer.

You take olaparib as a tablet twice a day.

Side effects of targeted therapy drugs

Targeted therapy drugs may cause side effects which will depend on the drug you are having. Always tell your cancer doctor or nurse about any side effects you have. There are often ways in which they can be managed.

Effects on the heart

Trastuzumab and pertuzumab may cause changes to the way the heart works. You will have tests to check your heart before and during treatment. If there are any heart problems, your cancer doctor may prescribe drugs to treat these, or stop trastuzumab or pertuzumab for a while.

We have more information about the side effects of trastuzuma and pertuzumab.

About our information

  • References

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

    National Institute for Health and Clinical Excellence (NICE). Pathways Advanced Breast Cancer, updated 2017 (accessed November 2017).

    F Cardoso et al 3rd ESO–ESMO. International Consensus Guidelines for Advanced Breast Cancer. (ABC 3) 2016.

    Bourke M et al Effective Treatment of Intractable Cutaneous Metastases of Breast Cancer with Electrochemotherapy: Ten-year Audit of Single Centre Experience. Breast Cancer Research and Treatment January 2017, Volume 161, Issue 2, pp 289–297.


  • 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 Editors; Dr Russell Burcombe, Consultant Clinical Oncologist; Professor Mike Dixon, Professor of Surgery & Consultant Surgeon; and 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.