About monoclonal antibodies

This page is about monoclonal antibodies (MAB). You can find information on

What monoclonal antibodies (MABs) are
How monoclonal antibodies work
Types of monoclonal antibodies
How you have monoclonal antibodies
General side effects of monoclonal antibodies

MABs are a type of biological therapy. Monoclonal just means all one type. So each MAB is a lot of copies of one type of antibody. It is now possible to make MABs in a laboratory.

There is information about antibodies and the immune system in our section about your body.

Monoclonal antibodies are designed to recognise and attach to specific proteins on the surface of cells. Each monoclonal antibody recognises one particular protein. They work in different ways depending on the protein they are targeting. So different monoclonal antibodies have to be made to target different types of cancer.

Many different monoclonal antibodies are already available to treat cancer. Some are licensed to treat particular types of cancer. Some newer types are still in clinical trials. Different monoclonal antibodies cause different side effects. It can take a long time to develop this type of treatment because making monoclonal antibodies can be very complicated.

There are 3 main types of monoclonal antibodies. They work in slightly different ways. They may

Trigger the immune system to attack cancer cells
Block signals telling cancer cells to divide
Carry cancer drugs or radiation to cancer cells

Trigger the immune system

Some monoclonal antibodies 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 monoclonal antibodies simply attach themselves to cancer cells, making them easier for the cells of the immune system to find them. These include

Rituximab (Mabthera) for non Hodgkin lymphoma (NHL) and some types of leukaemia
Alemtuzumab (MabCampath) for chronic lymphocytic leukaemia (CLL)

Below is a short video showing how monoclonal antibodies work when they trigger the immune system. Click on the arrow to watch it.

Other types of monoclonal antibodies attach themselves to immune cells so that the cells carry on producing cells to attack cancer cells. Ipilimumab for advanced melanoma skin cancer works by stimulating T-cells in the body’s immune system. T-cells help to fight cancer and disease. CTLA-4 is a molecule found on the surface of T-cells and it switches them off. Ipilimumab blocks CTLA-4 so that the T-cells stay switched on and active and can attack the cancer cells.

Block signals telling cancer cells to divide

Cancer cells often make large amounts of molecules called growth factor receptors. These sit on the cell surface and send signals to help the cell survive and divide. Some monoclonal antibodies stop growth factor receptors from working properly. So the cancer cell no longer receives the signals it needs. This type of MAB includes

Trastuzumab (Herceptin) for breast cancer and stomach cancer
Bevacizumab (Avastin) for advanced bowel cancer, breast cancer and some other cancers
Cetuximab (Erbitux) for advanced bowel cancer or in trials for other cancers
Panitumumab (Vectibix) for advanced bowel cancer

Another monoclonal antibody researchers are looking at is pertuzumab (Omnitarg). The growth factor receptor HER2 is found on some breast cancer and prostate cancer cells. Pertuzumab blocks (inhibits) this receptor.

Below is a video showing how monoclonal antibodies work when they stop cancer cells making proteins. Click on the arrow to watch it.

Carry cancer drugs or radiation to cancer cells

Some monoclonal antibodies have drugs or radiation attached to them. The MAB finds the cancer cells and delivers the drug or radiation directly to them. These are called conjugated MABs.

MABs that have a radioactive substance attached include

Ibritumomab (Zevalin) for non Hodgkin lymphoma (NHL) and some other cancers
Tositumomab (Bexxar) for non Hodgkin lymphoma (NHL)

Some MABs that have a drug attached are still in clinical trials. They include

Gemtuzumab ozogamicin (Mylotarg) – for acute leukaemia
ADEPT – for bowel cancer

Below is a video showing how monoclonal antibodies work when they carry cancer drugs or radiotherapy to cells. Click on the arrow to watch it.

There is more information about individual monoclonal antibodies in the cancer drug section and in the treatment sections for each type of cancer. Because some of these treatments are very new, you may find this information in the specific research pages for each type of cancer.

You have monoclonal antibody treatment through a drip (infusion) into a vein. How often you have treatment and how many treatments you need will depend on

Which monoclonal antibody you have
The type of cancer you have

All treatments have side effects. Some side effects depend on the type of cell the MAB is targeting. They may also depend on whether the MAB has a drug or radioactive substance attached to it.

The most common side effect of all monoclonal antibodies is an allergic reaction to the drug. This reaction is most likely to happen when you first have the treatment. You will have paracetamol and an antihistamine drug before you have the treatment to prevent a reaction. If you have a reaction, your doctor or nurse can usually control it by slowing down or stopping the drip for a while.

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