Abstract

Keeping a leash on cancer-killing cells Redirecting the immune system to attack tumor cells is proving to be an effective therapy against cancer. However, when patients are exposed to T cells engineered to recognize and attack cancer cells, there is a risk of runaway or excessive activity or of off-target effects, both of which can themselves be deadly. Wu et al. designed T cells expressing chimeric antigen receptors that recognize and attack cancer cells with an additional control system. This mechanism would allow a doctor administering the therapy to turn the engineered T cell “on” or “off” by administering a small molecule that is required along with cancer cell antigen to stimulate the T cells and activate their tumor cell–killing properties. Science , this issue p. 10.1126/science.aab4077