Beyond autologous ex vivo CAR-expressing cell therapies: Toward allogeneic and nucleated cell-free delivery systems of CAR

Abstract

The success of ex vivo chimeric antigen receptor (CAR)-T cell therapies has transformed the treatment of hematologic malignancies but remains limited by individualized manufacturing complexity and cost. Emerging in situ and in vivo CAR engineering platforms aim to overcome these barriers by programming patient immune cells directly within the body. Targeted lipid nanoparticles, synthetic DNA nanocarriers, and viral and non-viral delivery systems have demonstrated the ability to generate functional CAR-T cells without ex vivo manipulation, enabling scalable, on-demand immunotherapy. In parallel, advances in allogeneic "off-the-shelf" cellular therapies provide donor-derived products that can be manufactured at scale, cryopreserved, and delivered rapidly. Additional cell types are also being explored as vehicles for in vivo CAR delivery. Hybrid approaches that leverage allogeneic cells as carriers for CAR constructs may combine the scalability of off-the-shelf products with the speed and flexibility of in vivo engineering. Despite this promise, challenges remain, including cell-specific targeting, control of transgene persistence, immunogenicity, and regulatory considerations. Together, these innovations signal a paradigm shift in the generation and deployment of CAR-based cellular immunotherapies.

Keywords: CAR-T therapy; MT: Regular Issue; allogeneic cell therapy; cellular immunotherapy; enveloped delivery vehicles; gene transfer; in vivo gene delivery; lipid nanoparticles; mRNA therapeutics; synthetic DNA nanocarriers.