A Study of Zanidatamab (ZW25) With Evorpacept (ALX148) in Patients With Advanced HER2-expressing Cancer

Inclusion Criteria

• •Locally advanced (inoperable) and/or metastatic HER2-expressing cancer based on local or central laboratory test results as follows:
• •* Parts 1 and 2: HER2-positive breast cancer as defined per American Society of Clinical Oncology (ASCO)/ College of American Pathologists (CAP) guidelines
• •* Parts 1 and 2: HER2-low breast cancer (defined as immunohistochemistry \[IHC\] 1+ or IHC 2+; AND is currently not and has never been HER2-positive per the ASCO/CAP guidelines)
• •* Part 2: HER2-positive gastroesophageal adenocarcinoma as defined per the ASCO/CAP gastric cancer-specific guidelines; or other HER2-overexpressing non-breast cancers (defined as IHC 3+; or IHC 2+ and in situ hybridization \[ISH\]+) per the ASCO/CAP guidelines for breast cancer
• •Progression after or during the most recent systemic regimen of treatment for advanced cancer. For both Part 1 and Part 2, prior therapies must have included approved agents known to confer clinical benefit.
• •* Subjects with HER2-positive breast cancer who did not receive trastuzumab or pertuzumab due to medical contraindications will not be eligible for this study
• •* Subjects with HER2-low breast cancer who have received prior HER2-targeted therapy (other than trastuzumab deruxtecan, which is allowed but not required) will not be eligible for this study
• •Measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1)
• •Willingness to undergo a new biopsy to provide a tumor tissue for central laboratory testing of HER2 protein expression and gene amplification by IHC and ISH assays, respectively
• •Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• •Adequate organ functions
• •Adequate cardiac left ventricular function, as defined by a left ventricular ejection fraction (LVEF) ≥ 50% as determined by either echocardiogram or multiple gated acquisition scan (MUGA) obtained within 4 weeks prior to first dose of study treatment