Rupert Bartsch, MD, Medical University Vienna, Vienna, Austria, gives an overview of the current standard of care treatments for patients with HER2-positive metastatic breast cancer, highlighting key studies that led to their approval. First-line treatment consists of taxane plus pertuzumab or trastuzumab and the preferred second-line treatment is ado-trastuzumab emtansine (T-DM1). Whilst third-line treatments are less well defined, patients are either treated with a combination of tucatinib, trastuzumab and capecitabin, or with an antibody-drug conjugate (ADC). Recently, the Phase 3 DESTINY-Breast03 trial (NCT03529110) showed a significantly improved progression-free survival (PFS) for patients treated with trastuzumab deruxtecan (T-DXd) over patients treated with T-DM1 as a second-line treatment. This interview took place at the European Society for Medical Oncology (ESMO) 2021 congress.