Role of antibody drug conjugates in the treatment of patients with breast cancer brain metastases

Breast cancer remains a leading cause of brain metastases (BM), which carry a poor prognosis. The current approach to managing BMs in breast cancer patients involves a combination of local therapies (surgery, radiotherapy) and systemic treatments. Developing newer antibody-drug conjugates (ADCs) has sparked a revolution in metastatic breast cancer (MBC) care. ADCs such as ado-trastuzumab emtansine, trastuzumab deruxtecan, and sacituzumab govitecan have demonstrated significant improvement in patient outcomes and are standard of care in the treatment of MBC. Most of the ADC registration studies included patients with stable BMs but excluded individuals with active BM, making intracranial (IC) response assessment a challenge. Promising data has recently emerged, suggesting relevant IC activity for certain ADCs and ongoing studies in patients with active BM that will expand our knowledge. This review aims to summarize the effectiveness of approved ADCs as well as promising new ADCs in development for breast cancer with BM.