T-Cell therapy has delivered promising results in early trials involving patients with acute lymphoblastic leukemia. Removing immune cells, training them to attack cancer and then reintroducing them into the body has emerged as a promising approach to overcoming the deadly disease. And researchers are now reporting a significant advance in this area, with one early experiment on advanced blood cancer patients producing "unprecedented" response rates of more than 93 percent.
Harnessing the body's own immune system to fight off cancer has been heralded as the fourth pillar in cancer therapies, joining chemotherapy, radiotherapy and surgical removal. While our immune system kicks itself into action as a virus begins to infect us, cancers are able to elude the predatory cells and continue to multiply and grow.
So scientists are exploring ways to give the immune system the upper hand, through what is known as immunotherapy. One arm of this involves harvesting the body's T cells, which are central to the immune response, and using gene transfer to equip them with potent molecules called chimeric antigen receptors (CARs).
When these CAR T cells are introduced back into the body through a vein, they recognize certain proteins on cancer cells, attach themselves and start to kill them off directly. And because these engineered cells can continue to multiply after being returned to the body, the thinking is that the therapy would not need to be administered on an ongoing basis.
Scientists are now reporting some truly impressive results from an ongoing study at Seattle's Fred Hutchinson Cancer Research Center. Beginning in 2013, the trial involved 29 patients with advanced blood cancer – specifically acute lymphoblastic leukemia, in which an overproduction of immature white blood cells crowd the bone marrow and stop the production of normal blood cells. Some of the patients had not responded to other treatments, previously relapsed and were not expected to survive more than a few months. The group received the experimental immunotherapy and of the 29 patients, 27 experienced sustained remissions. Following their infusions, these patients showed no trace of cancer in their bone marrow.