A new analysis of patients treated with Kite’s CAR-T therapy Yescarta has identified genetic signals associated with toxicity risk and points to a mechanism that could inform safer CAR-T designs. The study, published in Science Immunology, focused on how patient DNA—carried forward in autologous T cells—may shape CAR-T behavior in vivo. Researchers led by Mark Leick at Massachusetts General Hospital analyzed data from Kite’s Zuma-1 and Zuma-7 trials of axi-cel. In Zuma-1, mutations in STXBP2 stood out, with all six patients carrying the mutation experiencing toxicity after treatment, while the pattern was not seen in Zuma-7.