Genetically Altered T-cells a New Immunotherapy

The cancer fighters known as CAR T cells have proved their prowess in recent years. Three therapies using the altered T cells against lymphoma or leukemia have won U.S. Food and Drug Administration approval, and hundreds of trials are now unleashing them on other malignancies, including solid tumors. But the cells may soon have company. Researchers have equipped other immune guardians—natural killer cells and macrophages—with the same type of cancer-homing receptor, and the natural killer cells have made their debut in clinical trials.

CAR T cells—their name comes from the chimeric antigen receptor, or CAR, added to help the immune cells target cancer cells—inspired the new work. CAR natural killer (CAR NK) cells could be safer, faster to produce, and cheaper, and they may work in situations where T cells falter. CAR-carrying macrophages also have potential advantages, and one firm plans to launch the first clinical trials of these cells next year.

Although they aren't likely to replace CAR T cells, these alternative cancer fighters "could be an addition to the armamentarium of cell therapies," says hematologist and oncologist Katy Rezvani of the University of Texas MD Anderson Cancer Center in Houston. She is leading the first trial of CAR NK cells in the United States, which began in 2017, and organizing another that is due to start this year.

Making CAR T cells involves removing patients' own T cells and genetically altering them to attack cancer cells that carry a specific immune-stimulating molecule, or antigen. (All of the CAR T treatments approved so far target the CD19 protein on cancerous B cells, a type of immune cell.) The cells have produced impressive results in clinical trials—in one study, they triggered remissions in 83% of children with previously untreatable acute lymphoblastic leukemia. But some patients who have already undergone chemotherapy or radiation treatment may not have enough T cells left to donate. And these powerful immune warriors can trigger a potentially fatal flood of the immune system molecules known as cytokines or turn against normal body cells.

Read the article in its entirety at Science Mag here:
http://www.sciencemag.org/news/2018/09/engineered-natural-killer-cells-may-be-next-great-cancer-immunotherapy