This study will evaluate the safety and efficacy of trastuzumab deruxtecan (T-DXd) in participants with human epidermal growth factor receptor 2 (HER2)-low or HER2 immunohistochemistry (IHC) 0 (who are both hormone receptor \[HR\]-negative and HR-positive) unresectable and/or metastatic breast cancer.
Sign and date the main informed consent form
Must agree to provide a newly obtained or archival baseline biopsy from primary and/or metastatic lesion.
Pathologically documented Breast Cancer (BC) tumor
Is unresectable and/or metastatic.
Prior treatment with an antibody drug conjugate (ADC).
Uncontrolled or significant cardiovascular disease.
Has a corrected QT interval prolongation.
Has a history of (non-infectious) interstitial lung disease (ILD)/pneumonitis that required steroids, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at Screening.
Daiichi Sankyo
Lead sponsor
AstraZeneca
Collaborator