Antibody-Drug Conjugates in HR+ Breast Cancer: Where Are We Now and Where Are We Heading?

Hormone receptor-positive (HR+) breast cancer (BC) accounts for about 60-70% of all diagnosed BCs, and endocrine therapy has long been the hallmark of systemic treatment for this tumor subtype. However, the therapeutic paradigm of luminal BC has been overcome due to recent evidence of antibody-drug conjugate (ADC) activity (such as trastuzumab deruxtecan and sacituzumab govitecan) in pretreated metastatic HR+ BC patients. Therefore, nowadays, the identification of patients who can benefit more from this approach represents a new challenge, as does the management of new toxicities and the integration of these drugs into the therapeutic algorithm of HR+ metastatic BC patients.