CAR T Cells: Engineering a patient's immune cells to treat their cancer

Over the last two decades, targeted therapies like imatinib (Gleevec®)and trastuzumab (Herceptin®)—drugs that target cancer cells by homing in on specific molecular changes seen primarily in those cells—have also cemented themselves as standard treatments for many cancers. But over the past several years, immunotherapy—therapies that enlist and strengthen the power of a patient’s immune system to attack tumors—has emerged as what many in the cancer community now call the “fifth pillar” of cancer treatment.   A rapidly emerging immunotherapy approach is called adoptive cell transfer (ACT): collecting and using patients’ own immune cells to treat their cancer. There are several types of ACT (see “ACT: TILs, TCRs, and CARs”), but the one that is closest to producing a treatment approved by the Food and Drug Administration (FDA) is called CAR T-cell therapy. Until recently, the use of CAR T-cell therapy has been restricted to small clinical trials, largely in patients with advanced blood cancers. But these treatments have nevertheless captured the attention of researchers and the public alike because of the remarkable responses they have produced in some patients—both children and adults—for whom all other treatments had stopped working.