Dual Antibodies Reap Benefits Against HER2-Positive Metastatic Breast Cancer

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer represents a biologically and clinically distinct subset of breast cancer, and the introduction of targeted therapies for HER2-positive tumors (e.g., trastuzumab, lapatinib) has dramatically improved prognosis. Several new anti-HER2 agents are likely to be approved soon. Pertuzumab is a monoclonal antibody that binds to a HER2 epitope distinct from that of trastuzumab, thereby blocking dimerization of HER2 with other HER receptor subtypes and, in turn, impeding downstream signaling. Pertuzumab has minimal antitumor activity as a single agent but acts synergistically with trastuzumab. The industry-sponsored Clinical Evaluation of Pertuzumab and Trastuzumab (CLEOPATRA) stu…