Clinical Research Directory

Inclusion Criteria: * Aged ≥ 18 years (or the legal age of adulthood per country-specific regulation) at the time of signing the ICF, male or female. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or - Life expectancy of ≥ 6 months. * Histologically confirmed breast cancer with radiologically or otherwise documented locally advanced unresectable and/or metastatic disease. * HER2 positive confirmed by central laboratory. * Hormone receptor (HR) status confirmed by local laboratory. * Patients who have progressed after treatment containing within HER2 ADC * Presence of at least one measurable lesion according to the RECIST v1.1. * Adequate organ function Exclusion Criteria: * History of any other malignancy within 2 years prior to signing the ICF. * Prior use of doxorubicin with a cumulative in vivo dose of \> 360 mg/m2. * Adverse events from prior anti-tumor treatment that have not resolved to Grade ≤ 1 or baseline level according to CTCAE v6.0. * Uncontrolled or severe cardiovascular disease. * History of cerebrovascular accident within 6 months prior to randomization. * Current (non-infectious) interstitial lung disease (ILD)/pneumonia that requires steroid treatment. * Active infection. * Active tuberculosis. * Presence of spinal cord compression or clinically symptomatic central nervous system metastases. * Receipt of systemic anti-tumor treatment and immunotherapy, within 4 weeks prior to randomization * Pregnant or lactating women or women who plan to become pregnant during the study period. * History of immunodeficiency or history of organ transplantation.