Metastatic Gastroesophageal Junction (GEJ) Adenocarcinoma

There is an unmet medical need to treat people with advanced cancer in the stomach, or where the food pipe joins the stomach. These conditions are known as advanced gastric cancer or advanced gastroesophageal cancer (GEJ for short). Zolbetuximab is an approved treatment for people with advanced stomach (gastric) cancer or advanced GEJ cancer. Some people with stomach or GEJ cancer have a protein called Claudin 18.2 in their tumor. Zolbetuximab works by attaching to the Claudin 18.2 protein in their tumor. This switches on the body's immune system to attack the tumor. The main aim of the study is to collect information about zolbetuximab and other cancer treatments in people with advanced gastric or GEJ cancer. This includes safety information, how long people respond to treatment and how long people live for without their cancer getting worse. This study is about collecting information only. This is known as an observational study. The individual's doctor decides on treatment, not the sponsor (Astellas). This study will use information from European and Canadian health registries and databases to learn more about people with advanced gastric or GEJ cancers who used zolbetuximab and other cancer treatments. The entire study will last about 4 years.

Zolbetuximab is being studied in people with cancer in and around the stomach or where the food pipe (esophagus) joins the stomach, called gastroesophageal junction (GEJ) cancer. Zolbetuximab with chemotherapy may be used to treat stomach and GEJ cancer when the cancer cells do not have a protein called HER2 (human epidermal growth factor receptor 2) on their surface (HER2-negative) but do have a protein called Claudin 18.2 (Claudin 18.2-positive). Zolbetuximab is thought to work by attaching to the Claudin 18.2 protein in their tumor, which switches on the body's immune system to attack the tumor. Certain stomach and GEJ cancers may be treated with immunotherapy, which helps the body's immune system fight cancer. This study will give more information about how well zolbetuximab works when given with an immunotherapy medicine called pembrolizumab and chemotherapy. In this study, adults with stomach cancer or GEJ cancer will either be given zolbetuximab with pembrolizumab and chemotherapy or a placebo with pembrolizumab and chemotherapy. A placebo looks like zolbetuximab but doesn't have any medicine in it. The main aim of the study is to check how long people with stomach cancer and GEJ cancer live after treatment with zolbetuximab with pembrolizumab and chemotherapy compared to placebo with pembrolizumab and chemotherapy. Adults with locally advanced unresectable or metastatic stomach cancer or GEJ cancer can take part. Locally advanced means the cancer has spread to nearby tissue. Unresectable means the cancer cannot be removed by surgery. Metastatic means the cancer has spread to other parts of the body. A tumor sample (biopsy) of their cancer will have the Claudin 18.2 protein, PD-L1 protein, and be HER2-negative. They may have been previously treated with certain standard therapies. People can also take part if they need to take medicines like steroids to suppress their immune system. They cannot take part if they have blockages or bleeding in their gut, have specific uncontrollable cancers such as symptomatic or untreated cancers in the nervous system, or have a specific heart condition, or infections. The study treatments are either zolbetuximab with pembrolizumab and chemotherapy, or placebo with pembrolizumab and chemotherapy. People who take part will receive just 1 of the study treatments by chance. The people in the study and the study doctors will not know who takes which of the study treatments. Study treatment will be given in 6-week (42-day) cycles. The study treatment is mainly given to people slowly through a tube into a vein. This is called an infusion. People will receive study treatment as follows: Zolbetuximab or placebo: 1 infusion every 2 or 3 weeks (2 or 3 infusions in a cycle) together with: Chemotherapy (1 of the following types of chemotherapy): 1. CAPOX (capecitabine and oxaliplatin): 1 infusion of oxaliplatin every 3 weeks (2 infusions in a cycle). People will also take 1 tablet of capecitabine twice a day for 2 weeks (14 days) at the start of each cycle (Day 1) and again in the middle of each cycle (Day 22). After 8 study treatments people will receive capecitabine only. 2. Modified FOLFOX6 or mFOLFOX6 (5-fluorouracil, folinic acid and oxaliplatin): 1 infusion every 2 weeks (3 infusions in a cycle). After 12 study treatments people will receive folinic acid and fluorouracil only, instead of mFOLFOX6. Pembrolizumab: 1 infusion every 3 or 6 weeks (1 or 2 infusions in a cycle). People can be in the study and will receive study treatment until their cancer worsens, they cannot tolerate the study treatment, or they need to start another cancer treatment. People may receive pembrolizumab for up to 2 years. People will visit the clinic on certain days to receive their study treatment and have health checks. The study doctors will check if people had any medical problems from taking zolbetuximab or the other study treatments. On some visits they will have scans to check for any changes in their cancer. People will have the option of giving a tumor sample if they stop treatment because their cancer has worsened. People will visit the clinic after they stop their study treatment. People will be asked about any medical problems and will have a health check. People will continue to have scans every 9 or 12 weeks to check for any changes in their cancer. They will have telephone health checks every 3 months. The number of visits and checks done at each visit will depend on the health of each person and whether they completed their study treatment or not.

There is an unmet medical need to treat people with advanced cancer in the stomach and the junction area where the stomach joins the food pipe. These conditions are known as advanced or stomach (gastric) cancer and advanced gastroesophageal junction cancer (GEJ cancer for short). Zolbetuximab is an approved treatment in many countries for people with advanced stomach cancer and advanced GEJ cancer. Some people with these cancers have a protein called Claudin 18.2 on their tumor but they do not have a protein called HER2 (human epidermal growth factor receptor 2) on their surface (HER2-negative). Zolbetuximab works by attaching to the Claudin 18.2 protein on their tumor. This switches on the body's immune system to attack the tumor. In India, the standard chemotherapies used are mFOLFOX6 or CAPOX. The main aim of the study is to check the safety of zolbetuximab when given with mFOLFOX6 or CAPOX chemotherapies in people in India with advanced stomach or GEJ cancer. It will also check how well zolbetuximab controls stomach cancer and GEJ cancer when given with mFOLFOX6 or CAPOX.

This study is for people in South Korea who have cancer in or around the stomach (gastric cancer) or cancer where the food pipe (esophagus) joins the stomach, called gastroesophageal junction (GEJ) cancer. Their cancer is locally advanced, unresectable, or metastatic. Locally advanced means the cancer has spread to tissue close by. Unresectable means the cancer cannot be removed by surgery. Metastatic means the cancer has spread to other parts of the body. In South Korea, VYLOY is approved for the treatment of gastric cancer or GEJ cancer. The people in this study will receive VYLOY as part of their usual treatment for their cancer. In standard clinical practice VYLOY is given to people slowly through a tube into a vein. The main aim of the study is to collect information in a real-world setting about the safety of VYLOY in people with gastric cancer or GEJ cancer in clinics in South Korea. This study will also help researchers learn how long people's gastric cancer or GEJ cancer stays stable. This study is about collecting information only. This is known as an observational study. The individual's doctor decides on treatment, not the sponsor (Astellas). The study will last about 1 year (54 weeks).

This program is to provide zolbetuximab to people with stomach cancer or gastroesophageal junction (the junction between stomach and esophagus) cancer who have not yet been treated with chemotherapy, immunotherapy, or zolbetuximab and who have tested positive for claudin18.2 (a protein found in some cancer cells). People will work with their doctor to see if they are capable of being treated with zolbetuximab while they receive other standard medicines to treat their cancer. The program will allow people early access to zolbetuximab before the drug is fully approved. Zolbetuximab will be given through a vein. This is called an infusion. The infusion will happen during a person's treatment with other cancer medicines. Zolbetuximab will be given every 3 weeks. People will continue treatment until: they have medical problems (unwanted side effects) from the treatment; their cancer gets worse; they start other cancer treatment; they ask to stop treatment; or they do not come back for treatment. People will visit the clinic on certain days during their treatment. During these visits, the program doctors will check for any medical problems (unwanted side effects) from zolbetuximab, other cancer treatment, or both. At some visits, other checks will include a medical examination, laboratory tests and vital signs. Vital signs include temperature, pulse, and blood pressure. Also, blood samples will be taken. People will visit the clinic within 7 days after stopping treatment. The program doctors will check for any medical problems (unwanted side effects) from zolbetuximab or their cancer treatment. Other checks will include a medical examination, laboratory tests, and vital signs. Then, people will have a follow-up visit about 30 days after stopping treatment. If people are having no health problems, the follow-up visit can happen over the telephone.