The in vivo revolution in CAR-T therapy medicinal products: challenges and regulatory prospects

# The in vivo revolution in CAR-T therapy medicinal products: challenges and regulatory prospects *Published: 2026 May 22* Chimeric antigen receptor T-cell (CAR-T) therapy, a groundbreaking advancement in cancer immunotherapy, has demonstrated remarkable efficacy in treating hematological malignancies and autoimmune diseases. However, conventional ex vivo CAR-T therapy medicinal products face multiple limitations, including complex manufacturing processes, high production costs, and challenges in quality control and risk management. In recent years, the emergence of in vivo CAR-T therapy medicinal products using viral vector or lipid nanoparticle platforms has provided a promising new direction by simplifying manufacturing, enhancing scalability, lowering costs, and increasing accessibility, though it may introduce elevated risks such as off-target effects and immunogenicity. From a regulatory perspective, this article reviews the progress, technological strengths, and regulatory landscape of in vivo CAR-T therapy medicinal products. We analyze their potential benefits in manufacturability, scalability, and discuss challenges including quality control, safety risks, and mitigation strategies in drug development. We propose adaptive regulatory strategies together with early regulatory engagement and international coordination to accelerate the clinical translation and standardized use of this emerging modality. DOI: 10.1038/s41392-026-02633-4