Summary
This study is assessing the efficacy and safety of multiple therapy combinations in treating people with HER2-positive locally advanced or metastatic gastric (stomach) or gastro-oesophageal junction (GEJ) cancers with tumours expressing PD L1 CPS ≥ 1.
Eligible participants are randomly allocated into three treatment arms.
In Arm 1, participants will be given rilvegostomig immunotherapy + fluoropyrimidine chemotherapy (Capecitabine OR 5-FU) + a targeted therapy drug called T-DXd.
In Arm 2, participants will be given pembrolizumab immunotherapy + trastuzumab targeted therapy + either FP chemotherapy (5-FU plus cisplatin) or CAPOX chemotherapy (capecitabine plus oxaliplatin).
In Arm 3, participants will be given rilvegostomig immunotherapy + trastuzumab targeted therapy + either FP chemotherapy (5-FU plus cisplatin) or CAPOX chemotherapy (capecitabine plus oxaliplatin).
All treatments are administered intravenously, except Capecitabine which is administered orally.