A Study to Investigate Tislelizumab Administered as Subcutaneous Injection Versus Intravenous Infusion Plus Chemotherapy in Patients With Unresectable or Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma

To join this study, your doctor would need to confirm that you have stomach cancer that cannot be removed by surgery or has spread. You must not have had any previous treatment for this advanced stage of stomach cancer. Doctors will also need to be able to measure your cancer, and you'll need to provide some tissue from your tumour for testing.

There are also some general health requirements, including having generally good health and your body's organs working well. If you are a woman who could get pregnant, or a man who could father a child, you would need to agree to use effective birth control during the study and for several months afterwards.

You would not be able to join if you have certain other types of stomach cancer, active brain tumours that are causing symptoms, or certain autoimmune conditions. Your doctor will check all these detailed criteria to see if this study is right for you.

If you join this study, it will involve several stages: first, a 'screening period' to check if you're suitable. If you are, you'll then enter a 'treatment period' where you'll receive either the tislelizumab injection under the skin or the drip into a vein, along with standard chemotherapy, for a set amount of time. You'll have regular hospital visits for these treatments, and doctors will monitor your health and how the treatment is working with various tests and assessments.

After your treatment finishes, there will be a 'follow-up period' where your health will continue to be monitored for a longer time, even if you stop taking the study medication. The exact number of visits and the total length of your participation will be explained in detail by the study team, but it will involve regular appointments over a period that could last many months.