Targeted therapies

Targeted therapies are drugs that can attack specific breast cancer cells without harming too many normal cells.

These drugs are good at reaching very specific targets, such as proteins or enzymes on the surface of cancer cells. They then interfere with the processes in cells that help cancer grow.

Targeted therapies are less likely to affect normal cells than other treatments. This means people experience fewer side effects compared to other treatments such as chemotherapy.

There are several types of targeted therapies:

• HER2 targeted therapies are the best known targeted therapies and include Herceptin, Perjeta, Kadcyla and Tykerb. To control the cancer, they block the action of HER2 receptors on cells
• Antibody drug conjugates (also called 'targeted chemotherapy') such as Trodelvy or Enhertu for metastatic breast cancer
• Drugs that are CDK4/6 inhibitors, mTOR inhibitors, PIK3CA inhibitors
• Drugs that are PARP inhibitors.

Clinical trials and research are looking for new ways to identify targets in cancer cells.

How targeted therapies work

Targeted therapies work in a variety of ways. They:

• block growth factors from being able to increase the growth of cancer cells
• block the action of certain enzymes, proteins or other molecules to prevent cancer cells from growing and spreading
• deliver toxic substances directly to cancer cells to kill them without affecting normal cells.

Ongoing research is focused on developing new targeted therapies for breast cancer. These trials include:

• identifying new targets on breast cancer cells
• creating innovative drugs to improve treatment outcomes.

Over time, we expect more treatments to be developed.