Carcinoma, Renal Cell (Clear Cell Only)

This clinical trial is looking at UCB4594. This is the first time the drug is being tested in humans. UCB4594 is a type of drug called a monoclonal antibody. It has been designed to work by targeting a protein called human leucocyte antigen G (HLA-G) that is found in high levels on some cancer cells. By attaching itself to this protein it may help the immune system to attack and kill the cancer cells. The four main aims of the clinical trial are to find out: 1. The best dose of UCB4594 that can be given safely to participants in the trial. 2. What the side effects of UCB4594 are and how they can be managed. 3. What happens to UCB4594 inside the body and how it affects cancer cells. 4. Whether UCB4594 can cause cancer to shrink.