Trastuzumab-Deruxtecan (T-DXd; DS-8201) vs trastuzumab emtansine (T-DM1) in high-risk patients with HER2-positive, residual invasive early breast cancer (BC) after neoadjuvant therapy (NAT): a randomized, phase 3 trial (DESTINY-Breast05)

Background Patients with residual invasive disease after NAT are at greater risk for disease recurrence or death than those with a pathological complete response. The antibody-drug conjugate (ADC) T-DM1 was recently approved as postneoadjuvant treatment for patients with residual invasive disease (in breast and/or axillary nodes) after NAT and anti-HER2-treatment. T-DXd is a potent HER2-targeted ADC that was recently approved following phase 2 evidence (Modi NEJM 2020) for the treatment of patients with HER2-positive, unresectable/metastatic BC with ≥2 prior anti-HER2─based regimens (US) or prior chemotherapy and being refractory to or intolerant of standard treatments (Japan).