Furthermore, an ongoing phase II clinical trial assessing the use of trastuzumab–deruxtecan in the neoadjuvant setting in HER2-low HR+ tumors reported that patients diagnosed with localized, hormone receptor-positive, HER2-low breast cancer and subjected to trastuzumab–deruxtecan treatment in the neoadjuvant setting demonstrated an overall response rate of 75% in the absence of anastrozole, and 63% when administered in conjunction with anastrozole. This evidence concerns the gene ERBB2 and breast cancer.