Major Strides in HER2 Blockade for Metastatic Breast Cancer

Breast cancer that is characterized by amplification or overexpression of human epidermal growth factor receptor 2 (HER2) accounts for 15 to 20% of all forms of the disease. The advent of HER2-targeted drugs, such as trastuzumab, pertuzumab, lapatinib, and the antibody-drug conjugate trastuzumab emtansine, has revolutionized the treatment of both early-stage and metastatic HER2-positive breast cancer.1-4 The increasing availability of HER2-targeted agents has led to improved outcomes for patients with HER2-positive metastatic breast cancer, as reported in a study in which overall survival rose from a median of 38.7 months to 51.1 months from 2008 through 2012.5 The standard first-line . . .