• Randomized Phase II study of 417 patients who received neoadjuvant pertuzumab (P) or trastuzumab (H) or both with docetaxel (T) and the combination without T.
• pCR rates in breast: THP (45.8%), TH (29%), TP (24%), HP (16.8%).

This neoadjuvant data set actually predated the presentation of the Phase III CLEOPATRA study of pertuzumab (an anti-HER2 monoclonal antibody that inhibits receptor dimerization) in metastatic disease and provided a glimpse of what was to come by documenting the advantage of adding pertuzumab to trastuzumab/chemotherapy. Perhaps the most intriguing aspect of this study was a randomization arm with dual monoclonal antibody treatment with trastuzumab/pertuzumab alone. Although the outcomes with the all-biologic regimen were less impressive than with chemotherapy, approximately 1 in 6 patients experienced a pathologic complete response, and the hope is that specific predictive biomarkers may one day identify which of these patients don’t need chemotherapy. Importantly, for now the role of neoadjuvant pertuzumab outside a protocol setting remains undefined and is not used by investigators.