ERBB2 and breast cancer: However, the real paradigm shift in the HER2-low BC field is related to the use of new anti-HER2 antibody conjugated drugs (ADCs), whose good results in progression-free survival (PFS) and the response rate (RR) have been shown in several studies [62,63,64] and are deeply demonstrated by the results of the DESTINY-Breast 03 trial, which documents the significant benefit in terms of prognosis determined only by the novel ADC trastuzumab T-DXd [29].