Many news outlets have published exciting information on a new therapy for certain blood cell cancers such as some leukemias and lymphomas. This therapy, called chimeric antigen receptor (CAR) T-cell therapy, is being tested for treatment of acute lymphoblastic leukemia and other blood cell cancers that have stopped responding to traditional chemotherapy.
T cells are white blood cells that are part of the body’s immune defenses. They help identify and destroy abnormal or foreign cells—including some cancer cells. CAR T-cell therapy is an innovative treatment that modifies a person’s own T cells to be more effective at destroying the person’s cancer cells. Doctors take some of the person’s T cells from a blood sample and add a bit of genetic code (DNA) that helps those T cells recognize and attach to specific cancer cells. When they put the T cells back, they attack the person’s cancer.
Although conventional chemotherapy has become fairly successful at treating many blood cell cancers, there still are no good options for people in whom chemotherapy has stopped working. Recent tests of CAR-T cells in such people have shown a significant response in a majority of people. And some people had total remission. Thus, this treatment represents an exciting new therapeutic option for patients with some blood cell cancers. There are some limitations to this new treatment modality, though. The most important is that unlike drugs, which can be manufactured in large quantities, CAR-T cells must be custom made for each person individually. That means the technology is expensive and difficult to implement. Because of these factors, CAR T-cell treatment cannot be easily used outside of major medical centers in the developed world. The treatments will probably not be able to be done at all in the developing world.
Further study is needed to determine for how long remissions induced by CAR T-cell therapy will last. In addition, even though the treatment uses the person’s own cells, side effects of CAR T-cell infusion may be significant. The large number of T cells attacking the cancer all at the same time sometimes causes a big inflammatory reaction. Some patients require intensive care for organ failure after T-cell infusion. Neurologic complications may also occur.
CAR T-cells are an exciting advance in the therapy of certain cancers. They may be similarly effective in other tumor types that have not yet been studied. Unfortunately, this treatment modality is unlikely to be able to help affect the majority of the world’s cancer population unless an affordable product can be produced.