Adjuvant Trastuzumab, Pertuzumab Plus Docetaxel in the Treatment of Early HER2-positive Breast Cancer

In this study, patients who have been diagnosed with HER2-positive early breast cancer will be randomly allocated in a 1:1 ratio to receive either three 3-weekly cycles of trastuzumab, pertuzumab and docetaxel (TPD) for a total duration of 9 weeks, followed by three further cycles of chemotherapy (Group A) or three 3-weekly cycles of trastuzumab and docetaxel (TD) followed by three further cycles of chemotherapy and single-agent anti-HER2 antibody treatment to complete one year of anti-HER2 treatment (Group B). These systemic treatments may be administered either prior to breast surgery (as neoadjuvant treatment) or after breast surgery (as adjuvant treatment). The study participants are required to have histologically verified breast cancer with a moderate to high risk for breast cancer recurrence despite macroscopically complete surgery for the breast tumor. The moderate/high risk of breast cancer recurrence is defined by presence of cancer in the axillary lymph nodes, or if the axillary lymph nodes do not contain cancer, by presence of a tumor larger than one centimeter in the breast. The study patients are followed up during the study treatments and after their completion with physical examination, blood tests, cardiac tests and, whenever indicated, with imaging. Approximately 520 patients will be randomly allocated to each of the two groups. The study hypothesis is that the regimen containing TPD may be more effective than the Group B treatment despite its brief duration.