Potential effectiveness of combining bevacizumab with paclitaxel for treating HER2-positive metastatic breast cancer.

Although various first- to third-line HER2-targeted therapies have been established, the optimal sequence after third-line therapy has not been determined yet. Here, we describe seven patients with HER2-positive metastatic breast cancer who underwent bevacizumab (BV) and paclitaxel (PTX) combination therapy after several HER2-targeted therapies. Re-biopsy of metastatic sites was performed on four patients during the treatment prior to BV + PTX; three patients presented the same HER2-positive status as that of the primary tumor and two of whom achieved partial response. Four of seven patients achieved partial response and a 10-month median progression-free survival. Therefore, bevacizumab combined with paclitaxel is potentially effective in the treatment of HER2-positive metastatic breast cancer, if standard HER2-targeted therapy fails. © The Japan Society of Clinical Oncology 2021.