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 tissu…