About targeted cancer drug treatment

Targeted cancer drugs are treatments that change the way cells work and help the body to control the growth of cancer. They work by ‘targeting’ the differences that help a cancer cell to survive and grow.

You might have targeted cancer drugs as part of your treatment for advanced bowel cancer. Advanced bowel cancer is cancer that started in either the back passage (rectum) or large bowel (colon) and has spread to another part of the body.

What are targeted cancer drugs?

Cancer cells have changes in their genes (DNA) that make them different from normal cells. These changes mean that they behave differently. Cancer cells can grow faster than normal cells and sometimes spread. Targeted cancer drugs work by ‘targeting’ those differences that a cancer cell has.

Targeted drugs work in different ways. For example, they can:

  • stop cancer cells from dividing and growing
  • encourage the immune system to attack cancer cells
  • stop cancers from growing blood vessels

You might hear some targeted drugs called biological therapies.

When you might have targeted drug treatments

Some types of targeted drugs are used to treat advanced bowel cancer. They can shrink the cancer or slow its growth but they can't cure the cancer.

Whether you have targeted therapy depends on:

  • the type of cancer you have
  • how far the cancer has grown (the stage)
  • other treatments you've already had
  • whether your bowel cancer has changes (mutations) in a group of genes called RAS genes

Types of targeted cancer drugs

Cetuximab (Erbitux), panitumumab (Vectibix) and bevacizumab (Avastin)

Cetuximab, panitumumab and bevacizumab are types of monoclonal antibodies. Monoclonal antibodies work by recognising and finding specific proteins on cancer cells. Different types of cancer have different proteins.  Monoclonal antibodies stop particular proteins from binding to cancer cells or blocking it from triggering the cancer cells to divide and grow.

Diagram showing a monoclonal antibody attached to a cancer cell

Cetuxumab (Erbitux) and panitumumab (vectibix) work by blocking proteins on cancer cells called epidermal growth factor receptors (EGFR). Avastin stops the creation of blood vessels by cancer cells.

You might have monoclonal antibodies during or after chemotherapy.

Afilbercept​ (Zaltrap)

Aflibercept (Zaltrap) is an anti angiogenesis drugs. This means it stops the creation of blood vessels by the cancer cells.  

Angiogenesis means the growth of new blood vessels. A cancer needs a good blood supply to bring food and oxygen and remove waste products.

Some cancer drugs stop the blood supply to cancer cells. These drugs are called anti angiogenics.

Regorafenib (stivarga)

Regorefenib is a cancer growth blocker. 

It works by blocking particular proteins on cancer cells that encourage the cancer to grow. It also stops the cancer from growing blood vessels.

Are these drugs available in the UK?

Cetuximab and panitumumab

Cetuximab and panitumumab are available on the NHS for advanced bowel cancer throughout the UK.

You can have these drugs:

  • if genetic tests on your cancer cells show these drugs might help you
  • as the first treatment for your advanced cancer, in combination with chemotherapy

Bevacizumab​ and regorafenib

These drugs have been licensed to treat advanced bowel cancer. But they have not been approved by the National Institute for Health and Care Excellence (NICE) or the Scottish Medicines Consortium (SMC). So they are not routinely available as treatments on the NHS in the UK.


Aflibercept has been licensed to treat advanced bowel cancer. But it has not been approved by NICE. So it isn’t routinely available on the NHS in England, Wales or Northern Ireland.

Aflibercept is available in Scotland. The SMC have recommended aflibercept for advanced bowel cancer:

  • together with irinotecan and 5FU chemotherapy (FOLIFIRI)
  • as your second treatment for advanced bowel cancer, if your first treatment (which included oxaliplatin chemotherapy) is no longer working 

Having targeted drug treatment

You have your treatment as tablets or capsules, or through a tube into your bloodstream. This depends on the type of drug you have.

Tablets or capsules

You must take tablets and capsules according to the instructions your doctor or pharmacist gives you.

You should take the right dose, not more or less.

Talk to your specialist or advice line before you stop taking a cancer drug.

Into the bloodstream

You have some of these drugs through a tube into your bloodstream. A nurse puts a small tube into a vein in your hand or arm and connects the drip to it.

Or you might have a central line. This is a long plastic tube that gives the drug into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment.

General side effects

Side effects depend on the type of drug you are having, some of the common side effects include:

  • tiredness (fatigue)
  • loss of appetite 
  • a sore mouth 
  • low levels of blood cells 
  • feeling sick

Contact your doctor or nurse if you are having any problems. They can give you advice and medication to help with some side effects.

Targeted drugs and their side effects

Last reviewed: 
12 Nov 2018
  • Metastatic colorectal cancer
    ESMO clinical practice guidelines for diagnosis, treatment and follow up
    E van Cutsem and others
    Annals of Oncology 2014 Vol 25 (suppl 3): iii1-iii9

  • Colorectal cancer: the diagnosis and management of colorectal cancer
    The National Institute of Health and Care Excellence, November 2011

  • Panitumumab-FOLFOX4 treatment and RAS mutations in colorectal cancer.
    J Duillard and others
    New England Journal of Medicine 2013 Sep 12;369(11):1023-34

  • Frequency of KRAS, BRAF, and NRAS mutations in colorectal cancer
    C Vaughn and others
    Genes Chromosomes Cancer. 2011 May;50(5):307-12

  • NRAS mutations are rare in colorectal cancer
    N Irahara and others
    Diagnostic Molecular Pathology 2010 Sep;19(3):157-63

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