What is Targeted Therapy?

Targeted drugs are aimed at specific mutations/pathways in cancer cells. For example, in HER2 (human epidermal growth factor receptor 2) breast cancer, the surfaces of the breast cancer cells have an overabundance of the HER2 protein (that is, they have an over-expression of HER2). So treatment will be more effective if the patient receives targeted drugs designed to act specifically against the HER2 protein. Similarly, different types of targeted drugs are now available to specifically attack other abnormal growth pathways used by cancer cells.

Unlike chemotherapy, targeted drugs are less likely to harm the healthy cells of the patient. However, because responses to drugs differ from patient to patient, some patients may experience some side effects unique to targeted therapies. The most important thing is for the patient to talk things over with the attending doctor before deciding to receive targeted therapy so that both the patient and the attending doctor are clear on the treatment expectations.

Depending on the drug selected, targeted therapy may be delivered orally, by infusion (through a vein), or injected subcutaneously (under the skin). It may be used in conjunction with other treatments.

Targeted therapy drugs for breast cancer currently include:

• Anti-HER2 targeted therapy
• Angiogenesis inhibitors
• mTOR (mammalian target of rapamycin) inhibitors
• CDK4/6 (cyclin-dependent kinase 4/6) inhibitors
• PARP (poly (ADP-ribose) polymerase) inhibitors
• Immunotherapy