Antibody-drug conjugates in breast cancer: Marching from HER2-overexpression into HER2-low.

The recent decade has witnessed a vigorous prosper of antibody-drug conjugates (ADCs) in solid tumors including breast cancer. Integrating the specificity of monoclonal antibodies and potency of cytotoxic drugs, ADCs are capable of delivering cytotoxic agents directly to tumor cells and surrounding accomplices with heterogeneous antigen expression by exerting the distinctive bystander effect. Up till now, three ADCs (T-DM1, T-DXd and SG) have attained the official approval and stepped into clinical practices in breast cancer, with numerous promising products in the pipeline. As an unprecedented breast cancer subgroup identified following solidified drug benefit, the cognitive and therapeutic paradigm of HER2-low population which was previously thought lacking definite targets and efficacious regimens has been thoroughly rewritten by ADCs, and several encouraging achievements are expected in ongoing trials. Herein, we discuss the contrived knowledge, latest advancements and future perspectives of ADCs in HER2-overexpressing and HER2-low breast cancer. • HER2-low breast cancer is featured by a remarkable clinicopathological heterogeneity. • An antibody-drug conjugate (ADC) is integrated by monoclonal antibodies and cytotoxic payloads via chemical linkers. • With three approved and numerous latecomers, ADCs are promising in solving brain metastasis. • ADCs combined with other regimens are anticipated, while drug resistance and interstitial lung disease are noteworthy. [ABSTRACT FROM AUTHOR]