AZD0901 in participants with advanced solid tumours expressing Claudin18.2

Inclusion Criteria

• • Histologically confirmed adenocarcinoma of the stomach or gastroesophageal junction.
• • Advanced or metastatic GC/GEJC.
• • Maximum 2 prior lines of systemic treatment for unresectable or metastatic disease.
• Sub study 2 Specific Inclusion criteria:
• • Participants diagnosed with histologically confirmed metastatic or advanced PDAC.
• • Availability of an archival sample or a fresh tumour biopsy taken at screening.
• • No prior treatments for unresectable or metastatic disease. Prior neoadjuvant/adjuvant chemotherapy is permitted as long as participants progressed ≥ 6 months (183 days) from the last dose.
• Sub study 3 Specific Inclusion criteria
• •Histologically confirmed, unresectable advanced, or metastatic adenocarcinoma of biliary tract, including cholangiocarcinoma (intrahepatic or extrahepatic) and gallbladder carcinoma (NOTE: Ampullary cancers are not eligible).
• • Documented radiographic or clinical disease progression on or after at least one prior regimen and maximum 2 prior lines of systemic treatment for unresectable or metastatic disease.
• Master Exclusion Criteria applicable to all sub studies:
• • 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.
• • Participants with clinically significant ascites that require drainage.
• • A history of drug-induced non-infectious ILD/pneumonitis.
• • Central nervous system metastases or CNS pathology.
• • Peripheral neuropathy, sensory, or motor ≥ Grade 2 at screening.
• • History of another primary malignancy.
• • Prior exposure to any MMAE-based ADC.
• • Prior exposure to any CLDN18.2 targeted agents except anti-CLDN18.2 monoclonal antibody.
• Sub study 1 Specific