Avelumab is a new drug that could induce an immune response against tumour cells. It is in clinical trials for several different cancers, including gastric and gastroesophageal adenocarcinoma. One trial is currently exploring its use as a third line treatment for these cancers, for patients who have already received two other courses of therapy that have failed. It is given as one hour drip straight into a patient’s vein once every two weeks. If licensed for use in the UK, it could offer a novel treatment option for patients for whom other cancer treatments have not worked.