Study of AZD5863 in Adult Participants With Advanced or Metastatic Solid Tumors

Key Inclusion Criteria:

• Age ≥ 18 at the time of signing the informed consent

• Histologically confirmed diagnosis of adenocarcinoma of the stomach,gastro-esophageal junction, esophagus, or pancreas

• Must have at least one measurable lesion according to Response Evaluation Criteriain Solid Tumors (RECIST) v1.1

• Must show positive CLDN18.2 expression in tumor cells as determined by centralimmunohistochemistry (IHC)

• Eastern Cooperative Oncology Group Performance status (ECOG PS): 0-1 at screening

• Predicted life expectancy of ≥ 12 weeks

• Adequate organ and bone marrow function measured within 28 days prior to first doseas defined by the protocol

• Contraceptive use by men or women should be consistent with local regulations, asdefined by the protocol

• Must have received at least one prior line of systemic therapy in theadvanced/metastatic setting

Key Exclusion Criteria:

• Unresolved toxicity from prior anticancer therapy of Common Terminology Criteria forAdverse Events (CTCAE) Grade ≥ 2 except for those defined by the protocol

• Participant experienced unacceptable cytokine release syndrome (CRS) or ImmuneEffector Cell Associated Neurotoxicity (ICANS) following prior T cell engagers (TCE)or chimeric antigen receptor T (CAR-T) cell therapy

• Previous history of hemophagocytic lymphohistiocytosis (HLH) / macrophage activationsyndrome (MAS)

• Active or prior documented autoimmune or inflammatory disorders within 3 years ofstart of treatment

• central nervous system (CNS) metastases or CNS pathology, as defined by theprotocol, within 3 months prior to consent

• Infectious disease including active human immunodeficiency virus (HIV), activehepatitis B/C, uncontrolled infection with EBV, uncontrolled active systemic fungal,bacterial or other infection

• Cardiac conditions as defined by the protocol

• History of thromboembolic event within the past 3 months prior to the scheduledfirst dose of study intervention

• Participant requires chronic immunosuppressive therapy

• Participants on anticoagulation therapy