In vivo CAR T-cell generation in non-human primates using lentiviral vectors displaying a multi-domain fusion ligand

• Lentiviral vectors displaying T cell-activating and costimulatory molecules (VivoVecTM) generate CAR T-cells in vivo without lymphodepletion

• VivoVecTM administration in non-human primates generates anti-CD20 CAR T-cells in vivo leading to prolonged complete B cell depletion

Chimeric antigen receptor (CAR) T-cell therapies have demonstrated transformative efficacy in treating B-cell malignancies. However, high cost and manufacturing complexities hinder their widespread use. To overcome these hurdles, we have developed the VivoVecTM platform, a lentiviral vector capable of generating CAR T-cells in vivo. Here we describe the incorporation of T cell activation and costimulatory signals onto the surface of VivoVecTM particles (VVPs) in the form of a multi-domain fusion protein and show enhanced in vivo transduction and improved CAR-T cell antitumor functionality. Furthermore, in the absence of lymphodepleting chemotherapy, administration of VVPs into non-human primates resulted in the robust generation of anti-CD20 CAR T-cells and the complete depletion of B cells for more than 10 weeks. These data validate the VivoVecTM platform in a translationally relevant model and support its transition into human clinical testing, offering a paradigm shift in the field of CAR T-cell therapies.