In vivo TRAC-CAR T cells engineered with dual vectors demonstrate potent cancer control

Researchers report a dual-vector in vivo system that edits the TRAC locus in T cells by delivering Cas9 via enveloped delivery vehicles and HDR templates via AAV6 (AAV-hT7), enabling promoterless CAR insertion at TRAC and generation of TRAC-CAR T cells directly in humanized mice. The approach produced therapeutic levels of CAR T cells, induced B cell aplasia, and controlled tumors in models of B-ALL, multiple myeloma, and solid tumors, with improved specificity from anti-CD3-targeted EDVs and an evolved, serum-resistant AAV-hT7 capsid. This could bypass ex vivo manufacturing and enable broader access to CAR T therapies, though translational safety and durability remain to be fully evaluated in primate models.