Targeted cancer drugs

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 stomach cancer. Advanced stomach cancer is cancer that started in the stomach 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 do you have targeted drugs for stomach cancer?

You might have a type of targeted drug called trastuzumab (Herceptin) if your stomach cancer is advanced and it's HER2 positive. HER2  stands for human epidermal growth factor receptor 2.  Some cancers have large amounts of HER2 protein and are called HER2 positive cancers. 

A sample of your tumour (biopsy) will show if it’s HER2 positive.

Types of targeted cancer drugs for stomach cancer

Trastuzumab (Herceptin)

Trastuzumab has the brand name Herceptin. It’s a monoclonal antibody. Monoclonal antibodies work by attaching to proteins on or in cancer cells.

Diagram showing a monoclonal antibody attached to a cancer cell

Human epidermal growth factor receptor 2 (HER2) is a protein that makes cells grow and divide. 

Trastuzumab works by locking onto HER2 in the cancer cells. It both stops them from growing and kills them. Trastuzumab only works if your cancer is HER2 positive.


Ramucirumab is another type of monoclonal antibody. It targets a different protein – vascular endothelial growth factor receptor 2 (VEGFR2). This drug works by blocking the protein so that the cancer can’t develop the blood vessels it needs to grow.

Some studies have shown that ramucirumab is beneficial for people with advanced stomach cancer, when other treatments haven’t worked. At the moment it’s not routinely available in the UK.

How you have targeted cancer drugs

You can have targeted cancer drugs as:

  • a drip in your arm
  • an injection under the skin
  • a tablets

You have trastuzumab every 3 weeks. You have it with chemotherapy, normally into your blood stream through a drip in your arm.

Side effects of targeted cancer drugs 

The side effects of targeted cancer drugs are different depending on the drug you’re having. Not everyone gets all side effects.

Side effects include:

  • allergic reaction
  • diarrhoea
  • tiredness
  • flu-like symptoms including fever, muscle aches and sickness
  • low blood counts

Trastuzumab can cause some damage to the heart and you’ll have regular checks to study your heart function.


Researchers are looking into new types of targeted cancer drugs for stomach cancer. Some research is looking into using targeted drugs alongside chemotherapy to see how they work best together.

When you go home

Treatment for stomach cancer can be difficult to cope with. Tell your doctor or nurse about any problems or side effects you have. Your nurse will give you numbers to call if you have any problems at home.

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