On the heels of cancer immunotherapy's clinical success, NK cells - a long-known but underappreciated component of the innate immune system - are emerging as the hottest new tool to fight cancer, with the potential to be safer and more broadly effective than their adaptive immune system counterparts.
The excitement centers on the potential of NK cells to solve some of the challenges of chimeric antigen receptor (CAR) T cells, allowing companies to bring together the immune system's innate and adaptive arms in a more comprehensive approach to creating tumor immunotherapies.
"People who aren't in the field would certainly know about T cell CARs, but few people know about natural killer cells and the important role they play in the immune response against tumors. If you're looking for the next big thing to come down the road in cancer immunology, NK cells are certainly it," said Daniel Kaufman, professor of medicine and director of the Cell Therapy Program at the University of California San Diego.
Unlike T cells, which recognize a specific antigen to elicit cytotoxic activity, NK cells can non-specifically find and destroy tumor cells and other abnormal cells. In addition, their mechanism avoids some of the key liabilities of T cell therapies.
Despite producing some dramatic clinical results in blood cancers, CAR T cells are still on shaky ground because their potential to overstimulate the immune system can lead to severe, possibly fatal, toxicities.
That vulnerability was underscored earlier this month when FDA placed a temporary clinical hold on Juno Therapeutics Inc.'s Phase II trial of its JCAR015 CAR T therapeutic after two patient deaths from cerebral edema were reported. The trial - which restarted after five days, in patients not