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Monoclonal antibodies (MAB)

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. MABs are made in a laboratory.

How monoclonal antibodies work

Monoclonal antibodies recognise and attach to specific proteins produced by 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.

Types of monoclonal antibody

Monoclonal antibodies work in different ways and some work in more than one way. They may do one of the following:

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.

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

Block molecules that stop the immune system working (checkpoint inhibitors)

The immune system uses particular molecules to stop it being overactivated and damaging healthy cells. These are known as checkpoints.

Some cancer cells make high levels of checkpoint molecules to switch off immune system cells called T cells. T cells would normally attack the cancer cells.

Drugs that block checkpoint molecules are called checkpoint inhibitors.

They are a type of immunotherapy and include drugs that block CTLA-4, PD-1 and PD-L1 (programmed death ligand 1). 

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. Either by blocking the signal or the receptor itself. So the cancer cell no longer receives the signals it needs.

Below is a video showing how monoclonal antibodies work when they stop cancer cells making proteins. 

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.

Below is a video showing how monoclonal antibodies work when they carry cancer drugs or radiotherapy to cells.

All monoclonal antibodies have names that include 'mab' at the end of their generic name, for example:

  • trastuzumab (Herceptin)
  • bevacizumab (Avastin)
  • rituximab (Mabthera)

We haven't listed them all here but you can find more information about these and other individual monoclonal antibody treatments 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 information about these in the specific research pages for each type of cancer.

How you have monoclonal antibodies

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

General side effects of monoclonal treatment

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:

  • chills
  • fever
  • an itchy rash
  • feeling sick
  • breathlessness
  • wheezing
  • headaches
  • flushes and faintness
  • changes in blood pressure

Information and help

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