In a study involving more than 1,500 patients who were treated with chimeric antigen-receptor (CAR) T-cell therapy at the University of Pennsylvania (Penn) in Philadelphia and at Stanford University in California, just 2.3% and 3.4% of patients, respectively, later developed secondary cancers. Notably, none of the cancers were directly linked to CARs—with no insertions of CAR molecules into the secondary cancers, Endpoints News reported. Penn’s Carl June, MD, discussed the data, which have not been published in a scientific journal, yesterday at an event hosted by Friends of Cancer Research and the Parker Institute for Cancer Immunotherapy in Washington, DC. The FDA began investigating cases of CAR T-cell–cancer-linked cases late last year, and the agency now requires drug companies to add boxed warnings to the products (Cancer Discov 2024 Feb 1 [Epub]).