Neoadjuvant Trastuzumab, Pertuzumab and Tucatinib Without Chemotherapy in HER2-positive Breast Cancer: the TRAIN-4 Study

This study tests whether HER2-positive breast cancer patients can be effectively treated before surgery with targeted therapy (trastuzumab, pertuzumab, and tucatinib) alone — without any chemotherapy. It aims to determine if some patients can avoid the side effects of chemotherapy while still achieving complete tumor elimination. **You may be eligible if...** - You are 18 or older with newly diagnosed HER2-positive breast cancer (confirmed by biopsy) - Your tumor is large enough to require pre-surgery (neoadjuvant) treatment - Your general health is adequate and heart function is normal - You have not started any treatment for this cancer yet **You may NOT be eligible if...** - Your cancer has spread to distant organs (metastatic) - You have had prior treatment for breast cancer - You have significant heart disease or reduced heart function - You are pregnant or breastfeeding - You have conditions that interfere with absorbing oral medications Talk to your doctor to see if this trial is right for you.