AZD0901 in Participants With Advanced Solid Tumours Expressing Claudin18.2

Eligibility Criteria

The list below is a summarised eligibility criteria for the study – refer to the study protocol for full criteria.

Master Inclusion Criteria applicable to all sub studies:

• Participant must be ≥ 18 years or the legal age of consent at the time of signing the ICF.
• Participants who are CLDN18.2 positive.
• Must have at least one measurable lesion according to RECIST v1.1.
• ECOG performance status of 0 to 1 with no deterioration over the previous 2 weeks prior first day of dosing.
• Predicted life expectancy of ≥ 12 weeks.
• Adequate organ and bone marrowsoft, spongy tissue found in bones that makes blood cells function as defined by protocol.
• Body weight > 35 kg.
• Participants are willing to comply with contraception requirements.

Sub study 1 Specific Inclusion criteria:

• Histologically confirmed adenocarcinomacancer arising from mucus-producing glands in organs 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 tumoura tissue mass that forms from groups of unhealthy cells biopsyremoval of a section of tissue to analyse for cancer cells taken at screeningtesting for cancer or conditions that can lead to cancer before symptoms appear, also known as cancer screening.
• No prior treatments for unresectable or metastatic disease. Prior neoadjuvant/adjuvant chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells is permitted as long as participants progressed ≥ 6 months (183 days) from the last dosethe amount of medication taken.

Sub study 3 Specific Inclusion criteria

• Histologically confirmed, unresectable advanced, or metastatic adenocarcinoma of biliary tract, including cholangiocarcinoma (intrahepatic or extrahepatic) and gallbladder carcinomacancer arising from tissues that line organs (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.