Study for AZD4360 in Participants With Advanced Solid Tumours

The purpose of this study is to evaluate the safety, tolerability, PK, immunogenicity, pharmacodynamics, and preliminary efficacy of AZD4360 in adult participants with locally advanced or metastatic solid tumours selected for expression of CLDN18.2.

Inclusion Criteria: 1. Participant must be ≥ 18 at the time of signing the ICF. 2. Eastern cooperative oncology group performance status of 0-1 with no deterioration over the previous 2 weeks prior to baseline or day of first dosing. 3. Minimum life expectancy of 12 weeks in the opinion of the Investigator. 4 Adequate organ and marrow function, as defined by protocol. 5\. Contraceptive use by men or women should be consistent with local regulations, as defined by protocol. 6\. Histologically confirmed advanced or metastatic Pancreatic ductal adenocarcinoma (PDAC), Gastric or Gastroesophageal junction cancer (G/GEJC), and Biliary tract cancer (BTC) with documented positive CLDN18.2 expression. 7\. Participants must have received at least one prior line of systemic therapy in the advanced/metastatic disease. 8\. At least one measurable lesion according to RECIST v1.1. Exclusion Criteria: 1. Human Epidermal Growth Factor Receptor 2 (HER2) positive (3+ by IHC or 2+ by IHC and positive by in situ hybridisation) or indeterminate G/GEJC participants. 2. Unstable or active peptic ulcer disease or digestive tract bleeding including but not limited to clinically significant bleeding in the setting of prior CLDN18.2 directed therapy. 3. Participants with clinically significant ascites that require drainage. 4. Central nervous system (CNS) metastases or CNS pathology, as defined by protocol. 5. With spinal cord compression or with high risk of paralysis. 6. History of non-infectious interstitial lung disease/pneumonitis. 7. Participant has cardiac abnormalities, as defined by protocol. 8. History of another primary malignancy within 2 years prior to screening. 9. Known serologic status reflecting active hepatitis B or hepatitis C. 10. Known HIV infection that is not well controlled. 11. Active tuberculosis infection.