A review of HER2-targeted therapy in breast and ovarian cancer: lessons from antiquity - CLEOPATRA and PENELOPE.

Although breast and ovarian cancer have notable distinctions, there may exist parallel pathways that can be exploited for therapeutic gain. For example, the therapeutic arena in breast cancer has benefited greatly from available endocrine therapies as well as novel drugs designed to target the HER2 receptor, including trastuzumab, lapatinib, T-DM1 and pertuzumab. CLEOPATRA, a Phase III randomized clinical trial studying pertuzumab in women with HER2-amplified metastatic breast cancer, was practice-changing in 2014. Its counterpart, the Phase III randomized PENELOPE trial, was activated following promising Phase II data and studied pertuzumab in an enriched ovarian cancer patient population with low HER3 mRNA. This review will trace the development of anti-HER2 therapies in breast and ovarian cancer.