Targeted and immunotherapy drugs for breast cancer

You might have targeted or immunotherapy drugs as part of your treatment for breast cancer.

Targeted cancer drugs work by targeting the differences in cancer cells that help them to grow and survive.

Immunotherapy uses our immune system to fight cancer. It works by helping the immune system recognise and attack cancer cells.

When you might have targeted and immunotherapy treatment

These drugs are used in different situations to treat breast cancer. You might have this treatment:

  • before surgery - to shrink a cancer
  • after surgery - to reduce the risk of the cancer coming back
  • instead of surgery, if surgery is not an option for you
  • when other treatments don’t work or have stopped working
  • if the cancer has come back after treatment had finished (recurred)
  • if the cancer has spread to other parts of the body (secondary cancer)

Not all the targeted drugs will be suitable for you. Some are only available if the breast cancer cells have certain receptors. 

For example, some breast cancers have a change which means that they produce large amounts of human epidermal growth factor receptor 2 protein (HER2). These are called HER2 positive breast cancers. So in this situation, you have treatment that targets these HER2 receptors.

Between 15 and 20 out of every 100 people with breast cancer (between 15 to 20%) have HER2 positive breast cancer. A test on a sample of your cancer will show if it's HER2 positive.

An example of treatment that targets this receptor are monoclonal antibodies Open a glossary item. They attach to proteins on or in cancer cells.

Diagram showing a monoclonal antibody attached to a cancer cell

Depending on the drug, you might have it on its own, with other targeted drugs, or with other treatments such as chemotherapy. 

There are many different types of targeted and immunotherapy drugs. We describe some of the drugs used for breast cancer below.

Your doctor might recommend you have a drug called abemaciclib. This is a type of targeted therapy. You have it as adjuvant Open a glossary item treatment with:

This treatment is for people whose breast cancer has spread to lymph nodes in the armpit and has a high risk of coming back (recurrence). Your breast cancer must also be hormone receptor positive Open a glossary item and HER2 negative.

Your doctor will tell you more about this and if it’s suitable for you.

Neratinib belongs to a group of drugs called cancer growth blockers. They work by blocking the signalling processes that cancer cells use to divide.

You have neratinib treatment for early stage breast cancer Open a glossary item if it is:

  • hormone receptor positive
  • HER2 positive
  • and you have already had treatment with trastuzumab within the last year

Pembrolizumab is a type of immunotherapy. It stimulates the body's immune system to fight cancer cells.

It’s a possible treatment for people with triple negative breast cancer Open a glossary item that:

  • have an early stage breast cancer with a high risk of coming back (recurrence) or
  • has spread to surrounding tissue (locally advanced)

You have pembrolizumab with chemotherapy before surgery (neoadjuvant treatment Open a glossary item). This is to reduce the size of the cancer before surgery. You continue to have it on its own after your surgery (adjuvant treatment Open a glossary item).

Pertuzumab is also called Perjeta. It is a type of monoclonal antibody.

To have this drug your cancer needs to be HER2 positive. You might have a combination of trastuzumab and pertuzumab before surgery if you have:

  • early breast cancer that is at high risk of coming back
  • breast cancer that has spread to surrounding tissue (locally advanced breast cancer)
  • inflammatory breast cancer - a rare type of breast cancer 

You might have it with trastuzumab and chemotherapy after surgery for early breast cancer.

Trastuzumab is also known by its brand name Herceptin, Herzuma and Ontruzant. It's a monoclonal antibody. Monoclonal antibodies attach to proteins on or in cancer cells.

It's a treatment for cancers that have large amounts of a protein called human epidermal growth factor receptor 2 (HER2). This is called HER2 positive breast cancer.

You might have trastuzumab:

  • on its own
  • in combination with other drug treatments such as chemotherapy or another type of targeted drug
  • with other treatments, such as radiotherapy

You might have it before or after surgery. 

This treatment is made up of 2 drugs, trastuzumab, and a chemotherapy drug called deruxtecan.

You might have this if you have HER2 positive breast cancer that:

  • cannot be removed by surgery or
  • has spread to other parts of the body (secondary breast cancer)

It's for people who have already had treatment for HER2 positive breast cancer. Your doctor will tell you if this is an option for you.

Trastuzumab emtansine (Kadcyla) is a combination of 2 drugs:

  • trastuzumab 
  • emtansine - a chemotherapy drug

It is a treatment for HER2 positive early stage breast cancer Open a glossary item after surgery. It is only for people who had drug treatment before surgery. And when they had the operation the surgeon found cancer cells nearby either in the breast or lymph nodes.

Trastuzumab emtansine works by finding and attaching itself to the HER2 protein on the surface of the cancer cell. The emtansine then goes inside the cancer cell to destroy it.

This treatment is a combination of three drugs:

  • trastuzumab
  • tucatinib - a type of targeted drug called a tyrosine kinase inhibitor  Open a glossary item
  • capecitabine - a chemotherapy drug

You might have these drugs if you have HER2 positive breast cancer that has spread to:

•    surrounding tissue (locally advanced) or
•    other parts of the body (secondary breast cancer)

You must have already had two or more treatments for HER2 positive breast cancer before having this treatment.

Other targeted drugs for locally advanced breast cancer

There are other cancer growth blockers that your doctor might use to treat locally advanced breast cancer Open a glossary item. You have one of these drugs with a hormone therapy drug, so either an aromatase inhibitor Open a glossary item or fulvestrant. These include:

  • palbociclib
  • ribociclib
  • abemaciclib

These drugs are for breast cancer that is hormone receptor positive and HER2 negative. You have tests on your breast cancer cells to check for this.

Secondary breast cancer

Some of these drugs and other targeted and immunotherapy drugs are used to treat secondary breast cancer.

Side effects

Everyone is different and the side effects vary from person to person. You might have a few side effects. And they may be mild or more severe. The side effects you have depend on:

  • which drug you have
  • whether you have it alone or with other drugs
  • the amount of drug you have (the dose)
  • your general health

A side effect may get better or worse during your course of treatment. Or more side effects may develop as the treatment goes on. For more information about the side effects of your treatment, go to the individual drug pages.


Researchers are looking at new and different types of targeted and immunotherapy drugs for breast cancer.

They are also looking into different combinations. This includes combining them with chemotherapy or other types of drugs. They want to find out if they improve how well they work. 

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