Trastuzumab Rezetecan vs Trastuzumab Deruxtecan in the Neoadjuvant Treatment of HER2 Positive Breast Cancer

This is a single-center, randomized, open-label, phase II interventional study. Eligible patients will be randomized 1:1 to receive either Trastuzumab-rezetecan (4.8 mg/kg Q3W) or T-DXd (5.4 mg/kg Q3W) for 8 neoadjuvant cycles. After completing neoadjuvant treatment, patients will undergo definitive surgery, and tpCR will be assessed from resected specimens. Patients will then be followed up to monitor long-term efficacy (e.g., EFS) and late-onset adverse events. A total of 68 patients (34 per arm) will be enrolled to achieve the study's statistical objectives.