Paclitaxel, Trastuzumab, and Pertuzumab in the Treatment of Metastatic HER2-Positive Breast Cancer

The purpose of this study is to see if a combination of drugs can help to treat this type of cancer. One drug is a chemotherapy agent called paclitaxel (Taxol®). Paclitaxel will be given every week through the vein. Although the weekly schedule of paclitaxel is not included in the label, the schedule and dose of weekly paclitaxel have been studied and have been proven to be more effective than an old standard schedule. The other two work against HER2. One is called trastuzumab (Herceptin®) and it is commonly given to women with early HER2 positive breast cancer or with advanced HER2 positive breast cancer that has spread to other parts of the body. Trastuzumab will be given through the vein every 3 weeks (or every week at the doctor's discretion). The third drug, pertuzumab, is an investigational drug. It has not been approved by the Food and Drug Administration. It has been given in studies to over 800 people. It has been effective in treating HER2 positive breast cancer. Pertuzumab will be given every 3 weeks through the vein. This study is looking at the effectiveness of these three drugs together.