Antibody–Drug Conjugate Revolution in Breast Cancer: The Road Ahead

Antibody drug-conjugates (ADCs) have revolutionized the treatment of many types of cancer, including breast cancer. Recently, two new ADCs have been approved, trastuzumab deruxtecan and sacituzumab govitecan; both have demonstrated impressive improvements in overall survival, trastuzumab deruxtecan in all three subtypes of metastatic breast cancer and sacituzumab govitecan in luminal and triple negative metastatic breast cancer. These drugs are the results of significant progress and innovation in the construction of the three components of an ADC, the monoclonal antibody, the payload, and the linker, and of the discovery of new target antigens. ADC engineering has profoundly changed the paradigm of cancer treatment, on one side being effective on tumors considered inherently resistant to the payload class of drugs and on the other side demonstrating activity in tumors with very low target expression. Yet, it is likely that we are just at the beginning of a new era as the identification of new targets and the introduction of new ADC constructs and combinations will expand the field of ADC rapidly over the coming years.