Pertuzumab Plus Trastuzumab With or Without Chemotherapy Followed by Emtansine in ERBB2-Positive Metastatic Breast Cancer

In ERBB2 (formerly HER2)-positive metastatic breast cancer (MBC), combining trastuzumab and pertuzumab with taxane-based chemotherapy is the first line of standard care. Given that trastuzumab plus pertuzumab was proven effective in ERBB2-positive MBC, even without chemotherapy, whether the optimal first-line strategy could be trastuzumab plus pertuzumab alone instead of with chemotherapy is unresolved.