Experimental safety switch reduces severity of CAR-T immunotherapy-related side effects UNC Lineberger Comprehensive Cancer Center researchers have successfully used an experimental safety switch, incorporated as part of a chimeric antigen receptor T-cell (CAR-T) therapy, a type of immunotherapy, to reduce the severity of treatment side effects that sometimes occur. This advance was seen in a patient enrolled in a clinical trial using CAR-T to treat refractory acute B-cell leukemia. It demonstrates a proof-of-principle for possible expanded use of CAR-T immunotherapy paired with the safety switch. The researchers published their findings in the journal Blood as an ahead-of-print publication. With CAR-T therapy, T-cells from a patient's immune system are modified in a manufacturing facility to express part of an antibody that can bind to a surface protein on cancer cells. The modified T-cells, after being infused back into the patient, seek out and attack cancer cells throughout the body. Patients with leukemia or lymphoma have experienced complete remission when treated with CAR-T therapy but sometimes experience toxicities, which can be life-threatening, due to inflammatory responses or nervous system toxicities caused by the modified T-cells.