The Changing View of Anti-HER2 Therapies

Martine Piccart, MD, PhD, director of medicine at the Jules Bordet Institute in Brussels, Belgium, discusses the changing view of anti-HER2 therapies for patients with breast cancer.

Until now, Piccart says, physicians had a clear view that only patients with tumors that show HER2 amplification or overexpression can see benefit from anti-HER2 therapies. This belief has since been shaken, but Piccart remains optimistic. If anti-HER2 therapies can be offered to more women, Piccart believes this is good news, as these treatments are well tolerated.

One subgroup of patients who could see benefit from anti-HER2 therapy is those with HER2-negative disease. At completion of standard chemotherapy, patients' circulating tumor cells, if present, are HER2-positive. In an upcoming clinical trial, patients will be randomized to trastuzumab or no treatment to see if anti-HER2 therapy improves outcome.

There is a notion that HER2-negative tumors show mutation in the HER2 kinase domain. There are patients, Piccart says, who could benefit from irreversible HER2 tyrosine kinase inhibitors.

Clinical Pearls

These trials will not be simple to run, Piccart says, as the HER2 mutation is rare (approximate 2 percent of the entire breast cancer population).

• Anti-HER2 therapies may be beneficial for patients beyond those with tumors that show HER2 amplification or overexpression
• Anti-HER2 therapies are well tolerated