The expanding role of pertuzumab in the treatment of HER2-positive breast cancer.

Breast cancer tumors that demonstrate gene amplification or overexpression of human epidermal growth factor receptor 2 (HER2) are classified as HER2-positive. They account for approximately 15% of all breast cancers and represent an adverse prognostic factor. Over the past years, many new therapies have become available for the treatment of breast cancer. Particularly, the treatment of patients with HER2-positive breast cancer has developed with the arrival of anti-HER2 targeted therapies that have been proven to increase survival in both the metastatic and early-stage settings of the disease. Trastuzumab, a monoclonal antibody targeting HER2, significantly improves survival in HER2-positive breast cancer. Nevertheless, it is still a challenge to evolve anti-HER2 therapies, as the disease may progress. Pertuzumab inhibits HER2 by binding to a different HER2 epitope than trastuzumab and represents a complementary mechanism of action to trastuzumab. The efficacy and safety of pertuzumab in combination with trastuzumab with or without chemotherapy have been demonstrated in both advanced and early stages of HER2-positive breast cancer. Herein, we review the available data on the use of pertuzumab for the treatment of patients with HER2-positive breast cancer.