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Monoclonal antibodies (MABs)

Some monoclonal antibodies (MABs) are a type of immunotherapy. Monoclonal just means all one type. So each MAB is a lot of copies of one type of antibody. MABs are made in a laboratory.

Many different MABs are already available to treat cancer. Some are licensed to treat particular types of cancer. Some newer types are still in clinical trials.

How they work

A MAB works by recognising and finding specific proteins on cells. Some work on cancer cells, others target proteins on cells of the immune system.

Each MAB recognises one particular protein. They work in different ways depending on the protein they are targeting. 

Diagram showing a monoclonal antibody attached to a cancer cell

MABs work as an immunotherapy in different ways. Some MABs work in more than one way. 

Trigger the immune system

Some MABs trigger the immune system to attack and kill cancer cells.

Although cancer cells are abnormal, they develop from normal cells so they can be difficult for the immune system to spot. Some MABs attach themselves to cancer cells, making it easier for the cells of the immune system to find them. This process is called antibody-dependent cell-mediated cytotoxicity or ADCC.

Below is a short video showing how MABs work when they trigger the immune system.

Examples of MABS that work in this way include:

  • rituximab (Mabthera) – a treatment for chronic lymphocytic leukaemia (CLL) and some types of non Hodgkin lymphoma
  • cetuximab (Erbitux) – a treatment for advanced bowel cancer and head and neck cancer
  • trastuzumab (Herceptin) – used to treat breast cancer and stomach cancer

You can find more information about these in our list of cancer drugs. 

Help the immune system to attack cancer

Other MABs work by acting on cells of the immune system. For example, immunotherapies called checkpoint inhibitors block proteins that stop the immune system attacking cancer cells.

Checkpoint inhibitors block different proteins, including PD-1 and PD-L1 (programmed death ligand 1). So you might also hear some of these drugs called PD-1 inhibitors or PD-L1 inhibitors.

Examples of checkpoint inhibitors include:

  • ipilimumab (Yervoy) - a treatment for advanced melanoma
  • nivolumab (Opdivo)
  • pembrolizumab (Keytruda)

Nivolumab and pembrolizumab are used to treat different types of cancer, including Hodgkin lymphoma and melanoma.

Other monoclonal antibodies

Other MABs work in a more targeted way. For example, they can block signals that tell cancer cells to divide. You can read more about this in our information about targeted cancer drugs.

How you have them

You have MAB treatment as an injection under the skin (subcutaneous injection), or through a drip (infusion) into a vein. For some drugs, you have your first treatment into your vein, then further treatments as an injection under your skin. 

How often you have treatment and how many treatments you need will depend on:

  • which MAB you have
  • the type of cancer you have

Testing

Before you have some types of MAB you might need to have tests using some of your cancer cells or a blood sample to find out whether the treatment is likely to work. These tests look for changes in certain proteins or genes. 

You cancer specialist can tell you if this applies to your treatment. This is not the case for all MABs and you don’t always need this test.

To test your cancer cells, your specialist needs a sample (biopsy) of your cancer. They might be able to test some tissue from a biopsy or operation you have already had. 

Side effects

All treatments have side effects. These can vary depending on the type of MAB you have. 

Allergic reaction during treatment

A common side effect of some MABs is an allergic reaction to the drug. This reaction is most likely to happen during treatment and when you first have the treatment. 

If this is possible with your drug, you might have paracetamol, a steroid and an antihistamine drug before treatment to prevent a reaction.

An allergic reaction can include these symptoms, though you may not have all of them:

  • breathlessness
  • fever and chills
  • an itchy rash
  • flushes and faintness

Your nurse will monitor you and treat any symptoms if they happen.

General side effects

Side effects might include:

  • skin changes such as red and sore skin or an itchy rash
  • diarrhoea
  • tiredness
  • flu-like symptoms such as chills, fever, dizziness
  • feeling or being sick
Contact your doctor or nurse if you have these symptoms, particularly if you have diarrhoea, a rash or flu-like symptoms. They can decide whether you need treatment.

For more information about the side effects of your treatment, go to the individual drug pages. 

Last reviewed: 
06 Nov 2017
  • Cancer: Principles and Practice of Oncology (10th edition)
    VT De Vita, TS Lawrence and SA Rosenberg
    Lippincott, Williams and Wilkins, 2015

  • Electronic Medicines Compendium
    Accessed July, 2017

  • Recognizing and managing on toxicities in cancer immunotherapy
    L Yang and others
    Tumour Biology, 2017. Volume 39, Issue 3:1010428317694542

  • State of the art in anti-cancer mAbs
    SM Chiavenna and others
    Journal of Biomed Science, 2017. Volume 24, Issue 15

  • NK Cell-Mediated Antibody-Dependent Cellular Cytotoxicity in Cancer Immunotherapy
    W Wang and others
    Front Immunology, 2015. Volume 6, Issue 368

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. If you need additional references for this information please contact patientinformation@cancer.org.uk with details of the particular issue you are interested in.

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