Paclitaxel and trastuzumab are anticancer drugs commonly used to treat breast cancer. In this study, researchers want to assess the safety and effectiveness of combining paclitaxel, trastuzumab-MCC-DM1 (T-DM1), and pertuzumab in women with HER2-positive locally advanced or metastatic breast cancer.
T-DM1 and pertuzumab are investigational drugs. T-DM1 is made by linking a chemotherapy drug called DM1 to trastuzumab. T-DM1 works by attaching to the HER2 protein on cancer cells and then releasing the chemotherapy inside the cancer cells.
Pertuzumab is an antibody protein that also attaches to HER2 on cancer cells. T-DM1 and pertuzumab have demonstrated anticancer activity in laboratory studies. The effect was even stronger when T-DM1 and pertuzumab were given together instead of being given alone.