Targeted therapy for stomach cancer

Some people with stomach cancer have targeted therapy. It uses drugs to target specific molecules (such as proteins) on cancer cells or inside them. These molecules help send signals that tell cells to grow or divide. By targeting these molecules, the drugs stop the growth and spread of cancer cells and limit harm to normal cells. Targeted therapy may also be called molecular targeted therapy.

You may have targeted therapy to:

• kill stomach cancer cells
• stop or slow cancer cells from growing, dividing and spreading
• control symptoms of advanced stomach cancer (called palliative therapy)

Your healthcare team will consider your personal needs to plan the drugs, doses and schedules of targeted therapy. You may also receive other treatments.

There are 3 targeted therapy drugs that may be used for stomach cancer.

Some people with stomach cancer have too much of the HER2 protein on the surface of stomach cells (called HER2-positive stomach cancer). Having too much HER2 protein can help the cancer cells grow. Trastuzumab (Herceptin and biosimilars) works by attaching to the HER2 protein on the surface of stomach cancer cells to stop their growth.

HER2 status testing can be done on stomach tumours of people with advanced, metastatic or recurrent stomach cancer. If the stomach tumour has too much HER2 protein (called HER2 overexpression), you may be offered trastuzumab. Trastuzumab does not help people with HER2-negative stomach cancer.

Trastuzumab is given through a needle into the vein (intravenously, or IV). It is often given every 3 weeks along with the chemotherapy drugs cisplatin and either fluorouracil (also called 5-fluorouracil or 5-FU) or capecitabine (Xeloda). Trastuzumab alone can be continued after chemotherapy is finished. It is usually given until the stomach cancer stops responding to it.

Ramucirumab (Cyramza) is a monoclonal antibody that targets a substance called vascular endothelial growth factor (VEGF). VEGF helps cells form new blood vessels that carry oxygen and nutrients, which cells need to grow and develop.

Many cancer cells, including stomach cancer cells, make VEGF. Ramucirumab works by finding and attaching to VEGF and preventing cells from forming new blood vessels. This means the cells can't get oxygen and nutrients that they need to grow. Targeted therapy drugs like ramucirumab are also called anti-angiogenesis drugs because they stop new blood vessels from forming.

Ramucirumab is given through a needle into a vein every 2 weeks. It may be given alone or combined with the chemotherapy drug paclitaxel. Ramucirumab is used for advanced, metastatic or recurrent stomach cancer when other chemotherapy drugs no longer seem to be working (when the cancer is refractory to treatment).

The immune system normally stops itself from attacking normal cells in the body by using specific proteins called checkpoints, which are made by some immune system cells. Stomach cancer cells sometimes use these checkpoints to avoid being attacked by the immune system.

Nivolumab (Opdivo) is an immune checkpoint inhibitor drug that targets and blocks PD-1 checkpoint proteins so immune system cells can attack and kill the cancer cells. Nivolumab and other immune checkpoint inhibitors may be called immunotherapy.

When combined with chemotherapy (XELOX or FOLFOX chemotherapy drug combinations), nivolumab may be used to treat advanced or metastatic stomach cancer. Nivolumab is given through a needle into a vein (intravenous infusion) once every 2 or 3 weeks until the disease progresses or the side effects outweigh the benefits of having the treatment.

Pembrolizumab (Keytruda) is another immune checkpoint inhibitor drug that targets and blocks the PD-1 checkpoint protein. It can be used as a first-line therapy in combination with chemotherapy and trastuzumab for HER-2 positive stomach cancer that is locally advanced unresectable or metastatic.

Side effects can happen with any type of treatment for stomach cancer, but everyone's experience is different. Some people have many side effects. Other people have only a few side effects.

Targeted therapy attacks cancer cells but doesn't usually damage healthy cells, so there are usually fewer and less severe side effects than with chemotherapy or radiation therapy. Chemotherapy and radiation therapy can damage healthy cells along with cancer cells.

If you develop side effects, they can happen any time during, immediately after or a few days or weeks after targeted therapy. Sometimes late side effects develop months or years after targeted therapy. Most side effects go away on their own or can be treated, but some side effects may last a long time or become permanent.

Side effects of targeted therapy will depend mainly on the type of drug, the dose, how it's given, if it's given with chemotherapy and your overall health. Side effects of targeted therapy for stomach cancer can include:

• fatigue
• headache
• pain in the muscles and joints
• pain in the abdomen
• diarrhea
• low blood cell counts, which may cause infection, bleeding and fatigue
• heart problems, such as congestive heart failure, from trastuzumab

Tell your healthcare team if you have these side effects or others you think might be from targeted therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Details on specific drugs change regularly. Find out more about sources of drug information and where to get details on specific drugs.

Find out more about targeted therapy. To make the decisions that are right for you, ask your healthcare team questions about targeted therapy.