ERBB2 and breast cancer: (20) The results showed that compared to the physician’s choice of chemotherapy, T-DXd significantly improved progression-free survival (PFS) (9.9 months vs. 5.1 months, hazard ratio [HR] for disease progression or death=0.50, p<0.001; T-DXd vs. chemotherapy) and OS (23.4 months vs. 16.8 months, HR for death=0.64, p=0.001; T-DXd vs. chemotherapy) in patients with HER2-low breast cancers.