AZD0901 compared with Investigator’s choice of therapy in participants with second- or later-line advanced or metastatic gastric or gastroesophageal junction adenocarcinoma expressing Claudin18.2

Exclusion Criteria

• 1. Participants with known HER2 positive status as defined as IHC 3+ or IHC 2+/ISH + (Cases with HER2: CEP17 ratio ≥ 2 or an average HER2 copy number ≥ 6.0 signals/cell are considered positive by ISH). Participants must undergo local (or have had) HER2 testing by IHC/ISH, and the most recent result of HER2 status will be used to determine the eligibility.
• 2. Participant has significant or unstable gastric bleeding and/or untreated gastric ulcers.
• 3. CNS metastases or CNS pathology including: epilepsy, seizures, aphasia, or stroke within 3 months prior to consent, severe brain injury, dementia, Parkinson’s disease, neurodegenerative diseases, cerebellar disease, severe uncontrolled mental illness, psychosis, CNS involvement of autoimmune diseases.
• 4. Participant has known clinically significant corneal disease (eg, active keratitis or corneal ulcerations).
• 5. Persistent toxicities (CTCAE Grade ≥ 2) caused by previous anticancer therapy, excluding alopecia. Participants with irreversible toxicity that is not reasonably expected to be exacerbated by study intervention may be included (eg, hearing loss).
• 6. Prior exposure to any ADC with MMAE payload or any CLDN18.2 targeting treatment other than naked monoclonal antibody (eg, CLDN18.2 targeting CAR-T cell therapy, multi-specific antibody including targeting CLDN18.2, etc).