Chimeric Therapeutics halted its Phase I/II study of CHM-2101, a cadherin-17-targeted autologous CAR T for gastrointestinal cancers, after a second patient at the highest dose level experienced dose-limiting toxicities. The company said it would discontinue development of the therapy in its current form. Chimeric announced a pivot to an early-stage in vivo CAR program targeting the same cadherin-17 antigen. The shift aims to address clinical and operational challenges associated with autologous ex vivo CAR T approaches. The decision highlights how manufacturing and patient safety remain central determinants of platform direction, especially for solid-tumor CAR T programs where efficacy and toxicity profiles are tightly linked. Going forward, the company’s in vivo efforts will likely be watched for early tolerability signals, vector design choices, and how the in vivo strategy changes biodistribution and immune engagement compared with CHM-2101.