Taxanes in combination with trastuzumab and pertuzumab are the established first-line standard in the treatment of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. In the last years, several new HER2-targeted therapies, including antibody-drug conjugates (ADCs) and tyrosine kinase inhibitors, have been approved for therapy after trastuzumab or dual blockade. In this review, the current treatment algorithms are discussed, including these new treatment options. The ADC T-DM1 was the established second-line standard based on the results of the EMILIA trial. Recently, the DESTINY-Breast03 trial compared T-DM1 with the new ADC trastuzumab deruxtecan (T-DXd) in patients with disease progression after treatment with taxanes and trastuzumab. T-DXd was associated with an improved progression-free survival and a trend toward improved overall survival, establishing T-DXd as a new second-line standard. The HER2CLIMB trial demonstrated a significant progression-free survival and overall survival benefit for the tyrosine kinase inhibitor tucatinib in combination with trastuzumab and capecitabine after T-DM1 and trastuzumab/pertuzumab. This benefit was also observed in patients with active brain metastases defining this combination as the preferred second or third-line option in these patients. New treatment strategies in HER2-positive metastatic breast cancer have substantially improved the clinical outcome of these patients, including those with active brain metastases.