Our bodies normally make antibodies that attack viruses or bacteria. One type of experimental treatment for cancer is the use of antibodies that can attach to cancer cells, allowing the immune system to kill them. In this study, investigators are using a special “monoclonal” antibody designed to find and attach to cancer cells.
Monoclonal antibodies bind to very few normal cells. This could help cancer treatment in two ways: The body’s own immune system might work to destroy cancer cells that are tagged with an antibody. Doctors could also attach chemotherapy drugs or a radioactive substance to the antibodies, allowing the antibodies to deliver treatment directly to the cancer cells when they attach to them.
The first monoclonal antibodies were made from antibodies grown in mice. They caused an antibody response in humans after one exposure. Now it is possible to make “chimeric” monoclonal antibodies that are more like human antibodies, and thus do not produce the same reactions with repeated doses. The antibody being evaluated in this study is called chimeric G250 (cG250). It has been used to treat patients many times over a long period. Doctors hope that cG250 will be more effective than the mouse antibody to treat patients with advanced kidney cancer.
The purpose of this study is to find the largest single dose of cG250 tagged with a radioactive substance (yttrium-90) that can be given safely to patients with advanced kidney cancer; see where the tagged monoclonal antibody goes in the body, how much of it attaches to the tumor, and how long it stays in the blood; and see whether the immune system raises a response and produces antibodies against cG250.