Preclinical data from Weill Cornell Medicine and Roswell Park Comprehensive Cancer Center show that intravesical CAR T cells can control bladder tumors in mice. In a Journal of Experimental Medicine report, researchers engineered CAR T cells targeting MUC16 and delivered them directly into the bladder via catheter. The team framed MUC16 as a clinically relevant target for bladder cancer and highlighted that intravesical delivery—an established urology route—may offer a simpler, potentially more effective strategy than systemic approaches that face poor solid-tumor infiltration and off-target toxicity. The study adds momentum to solid-tumor CAR T development by emphasizing local delivery as a practical path to improve tumor exposure and safety in urologic settings.