sonesitatug vedotin is an experimental drug that combines an antibody with a chemotherapy agent. It is given through an IV and is designed to find and attach to cancer cells that have a special protein, then release the chemotherapy directly onto those cells. In this study it is being tested to see if it works better than the current standard treatments.

capecitabine is an oral chemotherapy pill that the body changes into a drug that stops cancer cells from growing. In the trial it is taken by mouth and is part of the treatment plan being compared to the usual care for advanced stomach and esophageal cancers.

rilvegostomig is a new drug given by IV infusion that works on the immune system to help the body fight cancer. It is being tested together with sonesitatug vedotin and capecitabine to see if the combination improves patients’ outcomes.

oxaliplatin is a chemotherapy medicine that is given by IV infusion. It is part of the standard chemotherapy regimens for stomach and esophageal cancers and is used in the trial as a reference treatment to compare the new drugs against.

folinic acid (also called calcium folinate) is a vitamin‑like substance given by IV infusion. It is used together with certain chemotherapy drugs to reduce side effects and help the chemotherapy work better. In the study it is part of the standard treatment arm.

fluorouracil is a chemotherapy drug given by IV infusion. It interferes with the cancer cells’ ability to make DNA, slowing their growth. It is a common component of standard therapy for stomach and esophageal cancers and serves as a comparator in this trial.

mycophenolate mofetil is an oral medication that suppresses the immune system. In this study it is used as background therapy for patients who need immune suppression, such as those receiving certain biologic drugs.

AZD0901 is a code‑named experimental drug given by IV infusion. It is being tested as a new therapy to see if it can improve outcomes for patients with advanced gastric or esophageal cancers.

infliximab (sold as Inflectra) is a biologic medicine given by IV infusion that blocks a protein called TNF‑alpha, which can help reduce inflammation and may have effects on cancer growth. It is included as background therapy for some patients in the trial.

nivolumab (sold as OPDIVO) is an immunotherapy drug given by IV infusion. It helps the immune system recognize and attack cancer cells. In this study it is tested as a potential new treatment option.

zolbetuximab is a monoclonal antibody given by IV infusion that targets a protein called CLDN18.2 on certain cancer cells. It is used as a comparator drug to evaluate how well the new treatment works.

Gastric cancer – A malignant tumor that starts in the lining of the stomach. Abnormal cells grow and can form a mass that invades the stomach wall. Over time the tumor may spread to nearby lymph nodes. It can also extend beyond the stomach to other organs. The disease often progresses silently until it becomes larger.

Gastroesophageal junction adenocarcinoma – Cancer that arises at the point where the esophagus meets the stomach. It begins in glandular cells of this junction and enlarges into a tumor. The growth can infiltrate surrounding tissues and involve nearby lymph nodes. As it advances, cancer cells may travel to distant parts of the body. The condition typically develops slowly at first and then accelerates.

Esophageal cancer expressing Claudin‑18.2 – A form of esophageal cancer whose cells display the protein Claudin‑18.2 on their surface. The tumor originates in the esophageal lining and expands into a mass. It can thicken the esophageal wall and narrow the passage for food. The disease may spread locally to surrounding structures and to distant sites. Progression often follows a pattern of gradual enlargement followed by faster invasion.