A Study to Compare DB-1303/BNT323 Versus T-DM1 in Breast Cancer
This study is designed to compare efficacy and safety of DB-1303/BNT323 versus T-DM1 in HER2-positive, unresectable and/or metastatic breast cancer patients previously treated with trastuzumab and taxane.
- EligibilityCriteria: Inclusion Criteria:  Male or female adults ≥ 18 years at the time of voluntary signing of informed consent. Pathologically confirmed unresectable or metastatic HER2 positive breast cancer previously treated with trastuzumab and taxane Eastern Cooperative Oncology Group (ECOG) performance status score is 0 or 1. Presence of at least one measurable lesion according to RECIST v1.1 Expected survival time ≥ 12 weeks. Patients must give informed consent to this study and voluntarily sign written informed consent form prior to the study.  Exclusion Criteria:  Prior anti-HER2 ADC therapy. Previous history of interstitial lung disease/noninfectious pneumonitis/radiation pneumonitis requiring steroid therapy. Known serious hypersensitivity to the active ingredients of the study drug, inactive ingredients in the formulation, or other antibody drugs. Multiple primary malignancies within 3 years, except for adequately resected non-melanoma skin cancer, curatively treated in situ tumor, or contralateral breast cancer Uncontrolled infection requiring intravenous antibiotics, antiviral or antifungal agents, autoimmune disease requiring treatment, uncontrolled diabetes, hypertension, or other systemic disease that makes compliance with study procedures difficult Unrecovered toxicity from prior anticancer therapy, defined as toxicity (except for alopecia) not recovered to ≤Grade 1 (NCI-CTCAE v5.0) or baseline.  NOTE: Other protocol defined Inclusion/Exclusion criteria may apply. - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult