Targeted Therapies in South Africa

How does targeted therapy work?

These kinds of therapies are more effective and less harmful to normal cells. It acts on specific molecular targets which are associated with cancer, as compared to chemotherapy which acts on all dividing cancer cells. Specially designed to interact with its target, it keeps the cells from living longer than normal. It blocks tumor cell proliferation and turns off the signals that tell cancer cells to grow and divide. They are chemical entities that specifically target a protein or enzyme that carries a mutation that targets cancer cells.

Types of targeted therapy

Small molecule drugs: Theses drugs act by blocking the process that helps the multiplication and spread of cancer cells. They keep the tissue around the tumor from making blood vessels, which bring the tumor nutrients. This works by starving the tumor through keeping new blood vessels from developing.

Monoclonal antibodies: These drugs act by blocking a specific target on the outside of cancer cells or in the area around cancer. They can also directly send toxic substances to the cancer cells. These drugs are given intravenously.

Disadvantages of targeted therapy

Having the target does not necessarily mean that the tumor will respond to the drug. In addition, the drug might initially work but then stop. Targeted therapy may not work if the tumor does not have the target. Most times targeted therapy has to be combined with other cancer treatments such as chemotherapy.

Examples of targeted therapies include:

Breast cancer: most breast cancer has an excess of a protein called human epidermal growth factor receptor. This protein is responsible for the growth of tumor cells.

Colorectal cancer: These cancers make too much of a protein called (EGFR) epidermal growth factor receptor. Drugs that block EGFR help to stop and slow cancer growth.

Lung cancer: Drugs that block EGFR slows down lung cancer. Targeted therapy for lung cancer is also available with a mutation in the ALK gene.

Melanoma: Half of the melanomas have a mutation in the BRAF gene. BRAF mutations make good drug targets. However, these drugs can be risky if you do not have the BRAF gene.

Side effects include:

• Skin problems
• High blood pressure
• Blood clotting
• Slow healing of wounds
• Heart damage
• Fatigue
• Nausea and vomiting
• Edema

Conclusion

Targeted therapy is the focus of development of anticancer drugs. As such it is key to precision medicine, which uses information about your genes and proteins to prevent, diagnose and treat cancer.

Most targeted therapies have been approved by the food and drug administration (FDA) to treat specific types of cancer. Others are still being studied in human and animal clinical trials.