Weill Cornell Medicine and Roswell Park Comprehensive Cancer Center reported preclinical results showing intravesical delivery of MUC16-targeting CAR T cells can control bladder tumors in mice. The study identified MUC16 as a clinically relevant target and used catheter-based delivery directly into the bladder. Published in the Journal of Experimental Medicine, the work describes genetically engineered CAR T cells designed to target and kill bladder cancer cells, with intravesical administration producing tumor control in preclinical models. The investigators argue the bladder route could improve feasibility and therapeutic performance versus systemic approaches typically challenged by limited solid-tumor infiltration. The researchers co-led by Taha Merghoub, PhD, position the approach as a potential strategy for bladder-sparing treatment in high-risk patients who face recurrence, progression, or complications from cystectomy. They also note off-target and infiltration issues that have historically constrained CAR T expansion into solid tumors. While the findings remain preclinical, the study adds a concrete translational angle: a familiar urological administration route paired with a defined CAR target, MUC16, for direct access to tumor tissue.