ERBB2 and breast carcinoma: A total of seven HER2-directed ADCs (SYD985, ARX-788, A166, MRG002, ALT-P7, GQ1001 and SBT6050) are currently being investigated in clinical trials, among which SYD985 and ARX-788 showed greater potency in HER2-low breast cancer than T-DM1.