SAN FRANCISCO, March 18, 2026 — Scientists at University of California, San Francisco have reported a major advance in cell therapy, demonstrating that CAR-T cells can be generated directly inside the body. The study, published in Nature, introduces an in vivo engineering strategy that combines adeno-associated virus (AAV)-based gene delivery with Enveloped Delivery Vehicles (EDVs) and gene editing, potentially eliminating the need for complex ex vivo manufacturing.
CAR-T therapy has transformed treatment for certain blood cancers, but its current manufacturing process remains a major barrier. Typically, T cells are extracted from patients, genetically modified in specialized facilities, expanded, and reinfused—a process that can take weeks and cost hundreds of thousands of dollars. This complexity limits access for many patients. The new in vivo approach aims to bypass these challenges by reprogramming T cells directly within the patient’s body using EDV- and AAV-mediated delivery systems.
Led by Justin Eyquem, the research team demonstrated, for the first time, programmable, site-specific integration of a large DNA payload into human T cells in vivo. Unlike prior approaches relying on transient mRNA delivery or random viral integration, this platform achieves stable and precise insertion of a CAR transgene at a defined genomic site.
The system is built on a dual-vector strategy integrating EDV, CRISPR, and AAV technologies. One component—an engineered Enveloped Delivery Vehicle—delivers CRISPR-Cas9 ribonucleoproteins directly into T cells. These EDVs resemble lentiviral particles but deliver protein complexes rather than DNA, enabling transient, precise genome editing without permanent vector integration. The second component uses an adeno-associated virus to deliver the CAR DNA template required for homology-directed repair.
The AAV vector plays a critical role by enabling efficient nuclear delivery of the donor DNA template, while the EDV ensures targeted and cell-specific delivery of the editing machinery. Together, these systems allow precise insertion of the CAR construct into the TRAC locus, ensuring controlled and physiologically relevant expression in T cells. Importantly, the intersection of EDV and AAV delivery confers an additional layer of specificity—only cells receiving both components undergo successful genome engineering.
To further enhance in vivo performance, the researchers engineered improved delivery features, including T cell-targeting mechanisms on EDVs and optimized AAV capsids capable of overcoming traditional barriers to immune cell transduction. These innovations address long-standing challenges in delivering gene-editing tools to circulating T cells.
Preclinical results were highly compelling. In humanized mouse models, a single administration of the EDV-AAV system generated robust CAR-T cell populations and led to rapid tumor clearance in aggressive leukemia and multiple myeloma models. Remarkably, the approach also demonstrated efficacy in a solid tumor model—an area where conventional CAR-T therapies have historically struggled. In some cases, engineered CAR-T cells accounted for up to 40% of immune cells in certain tissues.
Compared to traditional lentiviral approaches, the EDV-AAV platform demonstrated superior precision and efficacy. By inserting the CAR construct into the TRAC locus, each engineered T cell expresses a consistent and functional level of CAR, avoiding the variability associated with random integration. Additionally, the use of a promoterless CAR cassette ensures that gene expression occurs only after correct integration in T cells, reducing the risk of off-target effects.
Beyond efficacy, the combined EDV and AAV strategy offers important clinical advantages. It has the potential to eliminate ex vivo manufacturing, significantly reduce costs and treatment delays, and remove the need for lymphodepleting chemotherapy. These improvements could expand access to CAR-T therapies and improve tolerability for patients.
To advance the platform toward clinical application, the technology has been licensed to Azalea Therapeutics. Early non-human primate studies have demonstrated successful in vivo CAR-T generation, substantial expansion of engineered T cells, and effective B cell depletion, along with a favorable safety profile. These findings support the feasibility of translating the EDV-AAV-CRISPR platform into human trials.
The initial clinical focus will be on CD19-directed CAR-T therapies for B cell malignancies and autoimmune diseases, with first-in-human studies anticipated by 2027. More broadly, the integration of EDV delivery, AAV vectors, and CRISPR precision provides a scalable framework for in vivo cell engineering, with potential applications across multiple therapeutic areas.
By combining EDV-mediated protein delivery with AAV-based gene transfer, this work represents a significant step toward next-generation cell therapies—offering a path to faster, more accessible, and highly precise treatments for patients worldwide.
