Targeted Therapy (Precision Medicine)

The term targeted therapy refers to a type of drug treatment. To stop cancer from growing and spreading, it attacks specific features of cancer cells, known as molecular targets. Sometimes it is referred to as molecular targeted therapy or biological therapy.  

A targeted therapy drug circulates throughout the body, targeting a specific molecular target within or on the surface of cancer cells. As molecular targets are involved in the growth and survival of cancer cells, blocking them can kill cancer cells or slow their growth while minimising damage to healthy cells.  

As a result of targeted therapy drugs, cancer growth can be controlled, and the signs and symptoms of cancer are reduced or even eliminated. There is a possibility that drugs may need to be taken for a more extended period. In addition, you will need to undergo regular tests to monitor the disease.  

Targeted therapy may not be suitable for all patients. To determine whether cancer cells contain a particular molecular target, your doctor will perform a test on them. Depending on a patient’s test results, different people with the same cancer type may receive other treatment options.  

In cancer treatment, targeted therapies have improved survival rates for several types of cancer, and many patients have responded well to these therapies. 

There are several cancer types for which targeted therapy drugs have been approved for use in Malaysia. A list of cancers includes blood cancers such as lymphoma and leukaemia; common cancers such as breast, bowel, lung, and melanoma; and other cancers such as head and neck, cervical, liver, kidney, ovarian, stomach, pancreatic, and sarcoma. 

Many targeted therapy drugs during pregnancy or breastfeeding are not recommended. If you wish to use contraception or become pregnant, you should consult your physician.  

Targeted therapy drugs fall into two main categories: 

• Monoclonal antibodies

  This refers to synthetic versions of immune system proteins called antibodies, which are part of the body's natural defence against infection. A manufactured antibody binds to a protein on the surface of cells or surrounding tissues and interferes with the survival or growth of cancer cells. 

• Small molecular inhibitors

  Cancer cells can be inhibited from growing by drugs that reach inside cancer cells and block certain enzymes and proteins.  

  A haematologist or medical oncologist usually prescribes specific therapy drugs. They are generally administered in cycles with periods of rest in between. Drugs used in targeted therapy may be administered alone or in combination with chemotherapy drugs. Medications for targeted therapy can be given as swallowed tablets, drips into a vein in your arm, or injections under the skin.  

  Depending on the cancer type, how it responds, and any side effects that may arise, some medications may need to be taken daily for months or even years.  

  It is imperative to note that targeted therapy drugs will only work if cancer contains a particular molecular target. There is no guarantee that the drug will kill the cancer cells even if cancer contains the target. Response to targeted therapy varies according to the type of cancer and the molecular target. In most cases, patients considered suitable for a specific type of therapy drug will respond to it.  

  Targeted therapy aims to minimise harm to healthy cells, but it can still have side effects. There will be various side effects depending on the drug you are taking and how your body responds to it. Targeted therapy may cause the following side effects: 

  • Redness, sensitivity to light, a rash or swelling, and dry, flaky skin are examples of skin problems 
  • Irritated eyes without blurred vision 
  • Tiredness 
  • Headaches 
  • Joint aches 
  • Fever 
  • Nausea 
  • Diarrhoea 
  • High blood pressure 

  It is less common for targeted therapy drugs to affect the heart, liver, or thyroid.  

  Most side effects are temporary, lasting from a few weeks to a few months, and will gradually improve over time or after stopping the medication. You may experience several side effects or none at all. Your treatment team can assist you in managing any side effects that you may be experiencing.  

  Any concerns regarding targeted therapy or any side effects you may experience should be discussed with your physician.