Allo-defensive, multiplex base-edited, anti-CD38 CAR T cells for "off-the-shelf" Immunotherapy

Chimeric antigen receptor (CAR) T cell therapies are being widely investigated in both autologous and allogeneic settings, with gene editing providing new strategies to address barriers to mismatched cell therapies. Currently "universal" donor derived T cell therapies require intensive lymphodepletion and are prone to host-mediated rejection. CD38, a transmembrane glycoprotein involved in cell activation and bioenergetics, is a promising immunotherapy target for haematological malignancies. Disruption of CD38 expression using base editing prevented fratricide between T cells expressing anti-CD38 CAR (CAR38). Additional base editing enabled generation of a "universal" donor CAR38-T cells, devoid of endogenous TCRab and Human Leukocyte Antigen (HLA) molecules after disruption of T Cell Receptor Beta Constant (TRBC), Beta-2 microglobulin (B2M), and Regulatory Factor X5 (RFX5). Removal of cell surface HLA expression enabled evasion of anti-HLA antibodies in sera from sensitised donors and reduced allo-stimulation in mixed lymphocyte cultures (MLCs), while TCRab disruption prevented allo-reactivity. In MLCs, CAR38 expression enabled potent "allo-defense" activity against CD38+ allo-reactive cells. Multiplex-base-edited CAR38-T cells exhibited antigen-specific anti-leukemic activity against human B, T, and myeloid malignancies and inhibited disease progression in humanised murine xenograft models. CAR38-T cells offer a potent "off-the-shelf" strategy against CD38+ haematological malignancies and plasma cells associated with autoimmunity.