Brief Summary
This is a Phase Ⅲ, randomized, open-label, Sponsor-blinded, 3-arm, global, multicenter study assessing the efficacy and safety of rilvegostomig in combination with fluoropyrimidine and T-DXd (Arm A) compared to trastuzumab, chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells, and pembrolizumab (Arm B) in HER2-positive locally advancedat a late stage, far along or metastatic gastric or GEJ adenocarcinomacancer arising from mucus-producing glands in organs participants whose tumors express PD L1 CPS ≥ 1. Rilvegostomig in combination with trastuzumab and chemotherapy will be evaluated in a separate arm (Arm C) to assess the contribution of each component in the experimental arm.
Intervention / Treatment
- Drug: Rilvegostomig
- Drug: Trastuzumab deruxtecan
- Drug: Trastuzumab
- Drug: Pembrolizumab
- Drug: 5-fluorouracil
- Drug: Capecitabine
- Drug: Cisplatin
- Drug: Oxaliplatin
Inclusion Criteria:
- HER2 positive for gastric cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs on a tumor biopsyremoval of a section of tissue to analyse for cancer cells.
- PD-L1 combined positive score (CPS) ≥ 1.
- Provision of tumor tissuea group of cells that work together to perform a function sample from recent biopsy adequate for HER2 and PD-L1 testing.
- Previously untreated, unresectable, locally advanced or metastatic gastric or GEJ adenocarcinoma.
- WHO or Eastern Cooperative Oncologythe study, diagnosis and treatment of cancer Group performance status of 0 or 1.
- Have measurable target disease assessed by the Investigator based on RECIST v1.1.
- Have adequate organ and bone marrowsoft, spongy tissue found in bones that makes blood cells function within 14 days before randomization.
- LVEF ≥ 55% within 28 days before randomization.
- Adequate treatment washout period before randomization.