Development of immune evasive strategies for allogeneic cell replacement therapies

Project Summary Cell therapy is a promising new modality to treat, and potentially cure, a variety of diseases. There are currently over a dozen cell therapy products approved by the FDA addressing a variety of diseases including cancer, Type 1 diabetes, and sickle cell disease. However, most of these approaches involve autologous cell transplants, which face challenges including unscalable manufacturing and complex logistics, impeding widespread accessibility. There is therefore a critical need to develop new approaches, such as allogeneic cell transplants, to lower costs and broaden access to these potentially curative therapies. Pluripotent stem cells represent a promising approach to allogeneic cell therapy by providing an unlimited supply of cells and the ability to differentiate to any cell type. A key limitation, however, is host immune rejection of the stem-cell derived product upon transplantation, which currently necessitates lifelong use of immunosuppressive drugs, which can be toxic. Thus, Aleutian Therapeutics (Aleutian) is developing an immune evasion technology using gene editing to overcome the current limitations of stem-cell derived cell therapies. Aleutian’s innovative novel technology involves gene editing of pluripotent stem cells so that stem cell-derived cell therapies can be transplanted without the need for immunosuppressive drugs. Aleutian’s academic collaborator has previously conducted animal studies demonstrating that a panel of 12 genetic edits is sufficient to enable human pluripotent stem cells to overcome the xenogeneic barrier and survive for nearly six months in fully immune competent mice. The objective of the proposed Phase I research is to ascertain the minimal number of edits required to overcome the xenogeneic complement and NK (natural killer) barriers. Extensive preliminary data suggest the inhibition of T cells, NK cells, and complement are essential to overcoming the xenogeneic barrier in mice. Specific Aim 1 focuses on determining the minimal edits required for protection from complement- dependent cytotoxicity, evaluating whether a single edit with human complement receptor type 1 (hCR1) suffices. Specific Aim 2 will identify the most effective genetic modifications for evading NK cell-mediated rejection, particularly investigating roles of H2-Kb and Qa1 proteins in a human pluripotent stem cell knockout background. Specific Aim 3 aims to combine these findings to develop a stem cell line with minimal genetic edits necessary for immune evasion, validated through in vivo testing in B cell-deficient mice. Successful completion of the proposed Phase I study will show the minimum number of edits required to achieve an immune evasive phenotype, which will inform Phase II pre-clinical studies.