Using monoclonal antibodies for the treatment of large bowel cancer

Monoclonal antibodies are drugs that recognise and bind to specific proteins (receptors) that are found on the surface of particular cancer cells or in the bloodstream.

On the surface of some cancer cells there are receptors known as epidermal growth factor receptors (EGFr). When growth factors attach to the receptor, the cancer cell is stimulated to grow and divide. The monoclonal antibody cetuximab (Erbitux®) locks onto the EGFr and may prevent the cancer cell from growing and dividing.

Cetuximab is currently used in combination with the chemotherapy drug irinotecan, to treat advanced or metastatic bowel cancer that has not been controlled by irinotecan given on its own or in combination with 5FU. It is given as a drip (infusion) into a vein.

Another monoclonal antibody called bevacizumab (Avastin®), which works in a slightly different way to cetuximab, is also being used to treat advanced cancers of the colon and rectum.

Some people can have an allergic reaction to monoclonal antibodies. This can cause you to have a flu-like reaction, a drop in blood pressure or feel sick. Other side effects include skin rashes and tiredness. The first dose is often given slowly, over a number of hours. You may be given some other drugs first to make a reaction less likely.