ARX788 in Breast Cancer With Low Expression of HER2

A single arm, phase 2 study of ARX788 in unresectable and/or metastatic breast cancer with low expression of HER2. Subjects should received ≥2 lines of systemic chemotherapy regimens for recurrent or metastatic disease, and for HR positive subjects, also need to have received ≥2-line endocrine therapy ± targeted therapy (including neoadjuvant/adjuvant therapy). HER2 low expression is defined as HER2 IHC 1+ or HER2 IHC 2+ and FISH negative. The ARX788 will be administered every 3 weeks (Q3W) intravenous (IV) infusion.