Targeted therapies for early breast cancer

Several targeted therapies are available for early breast cancer in Australia. Current treatments are:

• HER2 targeted therapies 
• antibody drug conjugates
• drugs that are CDK4/6 inhibitors, mTOR inhibitors, PIK3CA inhibitors.

Talk to your treating team for advice on the best treatment for your type of early breast cancer.

HER2 targeted therapies

Treatments block the action of HER2 receptors on cells to control the cancer. Targeted therapies for breast cancer that is HER2 positive are:

• trastuzumab
• trastuzumab emtansine (Kadcyla)
• pertuzumab (Perjeta)
• neratinib (Nerlynx) - less common

Read About HER2 targeted therapies.

CDK4/6 inhibitors

CDK4/6 inhibitor drugs may be given in high-risk early breast cancers. They are used in combination with hormone-blocking therapy to:

• reduce the risk of recurrence
• extend the time before the cancer spreads (progresses)
• improve overall survival

The CDK4/6 inhibitors used with hormone-blocking therapies (such as aromatase inhibitors) are:

• ribociclib (Kisqali)
• abemaciclib (Verzenio).

How CDK4/6 inhibitors work

CDK4/6 proteins are in healthy cells and cancer cells. They help control how quickly cells grow and divide.

In most oestrogen-receptor positive (ER+) breast cancers, CDK type 4 and 6 are found to be overactive. This causes the cells to grow and multiply more quickly.

A CDK inhibitor stops CDKs from being able to work in their usual way.

Read Treatments for HR+ early breast cancer.

PARP inhibitor for BRCA-associated cancer

A PARP inhibitor blocks an enzyme in cells called PARP. Blocking this enzyme stops cancer cells from repairing their damaged DNA. This causes the cancer cells to die.

It can be effective in treating HER2 negative breast cancer in people with the BRCA1 or BRCA2 gene mutation, who are at a high risk of the cancer returning.

The PARP inhibitor approved in BRCA-associated breast cancer is Olaparib (Lynparza).

Antibody drug conjugates

Antibody drug conjugates (ADCs) are available for the treatment of early breast cancer. The ADC used in Australia is Trastuzumab emtansine (Kadcyla).