The American Society of Clinical Oncologists (ASCO) has declared immunotherapy the Clinical Advance Of The Year for the second year running – a sentiment that is very much shared by the cancer research community as a whole. The term immunotherapy as a whole refers to therapeutic strategies that utilize the patient’s own immune system to fight cancer – an idea that is rooted in some exciting research dating back to the 1980s and that is now really coming into its own with the development of sophisticated technologies.
CAR-T immunotherapy is one of the two recent immunotherapy technologies that have shaken the world of clinical oncology. The idea behind CAR-T is to take the patient’s own immune cells, which are normally destined to fighting infection, and equip them with superior cancer-fighting weapons. Specifically, these cells are given extra “receptors”, molecules that sit on the cell surface and allow it to recognize specific cell types – in this case, cancer cells. The “beefed up” immune cells are then put back into the patient, where they have been shown to be extremely adept at recognizing and fighting cancer. This approach has been particularly successful in the treatment of blood cancer such as leukemia and lymphoma.
The other exciting news in immunotherapy is checkpoint immunotherapy. Understanding checkpoint immunotherapy requires some basic understanding of how the immune system works. T cells are a special type of cell belonging to the immune system that constantly patrol the body looking for signs of abnormality, such as an infection. When they run into another “unknown” cell, they verify its identity by checking the presence of certain molecules that are present on the surface of all cells in the body. If the T cell finds the correct molecules on the surface of the unknown cell, it moves on. If the unknown cell does not check out, perhaps because it is diseased, it carries an infection or is a cancer cell, the T cell attacks it and eventually kills it. When this happens, the whole immune cell mounts a complicated response to prevent the T cell attack from accidentally damaging healthy tissues. The molecules involved in this process are known as immune checkpoints. However, cancers often hijack this mechanism and use it prevent the immune system from fighting back properly. Immune checkpoint blockers are designed to stop this from happening, allowing the immune system to properly fight back against cancer.
Immune checkpoint inhibitors are giving very promising results in a variety of different tumors, including melanoma, lung cancer, breast and ovarian cancer. What’s more, checkpoint immunotherapy against a molecule known as PD-1 (which is a part of the checkpoint system) made history as the first therapy to be approved for patients who have elevated levels of the molecule, no matter what type of cancer they have. This is very exciting news for anyone involved in clinical oncology and anyone interested in cancer research as a whole. There is no doubt that 2018 is going to bring plenty of more exciting developments in the field!