1:Hemato-Oncology Program, Cima Universidad de Navarra, Pamplona, Spain.; 2:Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.; 3:Centro de Investigación Biomédica en Red de Cancer (CIBERONC), Madrid, Spain

CAR-T therapies have revolutionized cancer immunotherapy, achieving long-term responses in some B-cell malignancies. However, CAR-T cell approaches still present limitations for other hematological malignances as well as solid tumors, that compromise their therapeutic efficacy.

The immunosuppressive tumor microenvironment (TME) of solid tumors or the quality of T cells from heavily treated patients affect long-term persistence and functionality of CAR-T cells. Moreover, in some situations the fast and aggressive disease progression after relapse could hamper autologous CAR-T cell administration. Therefore, it is necessary to develop alternative strategies to make CAR-T therapies more efficient and accessible to all patients.

Allogeneic CAR-T cells are a valuable approach to reduce the risk of manufacture and/or therapeutic failure, as well as reduce the cost of the therapy. In this work we have explored the use of traditional CRISPR-based DNA-cleavage systems and novel DNA base editors, to deplete HLA-I and TCR complexes during CAR-T cell production, in order to avoid immune rejection and graft versus host disease. In addition, we have applied genome editing tools to introduce additional modifications in CAR-T cells to counteract immunosuppressive TME and to improve CAR-T cell efficacy. Moreover, we have combined genome editing technologies with virus-free gene-transfer strategies using Sleeping Beauty transposons, to generate highly innovative allogeneic CAR-T cells, that haven been fully characterized in vitro and in vivo. Finally, we have also implemented the generation of improved CAR-T cells at GMP level, in order to bring these innovative CAR-T cell product to the clinic.