The clinical impact of Chimeric Antigen Receptor T cell (CAR-T) technologies on hematological malignancies have revolutionized cancer treatment. However, current autologous CAR-T therapies face major roadblocks for mass adoption. These include high-cost, patient-specific manufacturing, inconsistent CAR-T yield and function due to inherently depleted patient immune systems, and life-threatening adverse events. NK cell therapies have the potential to overcome at least some of these deficiencies. NK cells utilize multiple anti-cancer receptors without risk of graft versus host disease. However, they have reduced longevity in vivo, which may necessitate multiple infusions, increasing the risk of their rejection by the patient. Both CAR-T and CAR-NK cells are subject to checkpoint blockades and other mechanisms of immunosuppression that diminish their killer function in vivo. To address these key deficiencies, we developed ‘off-the-shelf’, genetically-enhanced CAR-NK cells via induced pluripotent stem cells (iPSCs). Utilization of iPSCs as a renewable source for NK cells allows for consistent, precisely-defined immunotherapy and the capacity to gene-edit in multiple anti-cancer modes of action, which we have taken advantage of. The CAR-iNK cells can be cryopreserved, delivered on-demand for each patient, and crucially enable a major reduction in manufacturing cost.
The iPSCs are gene-edited to carry a CAR (specific for the adenocarcinoma neoantigen TAG72) and deleted of immune suppression gene(s) to enhance NK longevity and efficacy. Multiple stable-expressing clones have been developed to obtain the most functionally optimal variants. Unlike nearly all current allogeneic NK therapies, our iPSCs are derived from rare triple homozygous HLA donors, reducing the risk of host-mounted rejection of these iNK cells. The manufactured CAR-iNK cells display potent, on-target cytotoxic functionality against multiple ovarian cancer cell lines in vitro but do not kill cells from fresh healthy tissue. They are free of any oncogene mutations and are generated under clinic ready conditions. In vivo, these iNK cells demonstrate significant cytotoxicity against solid ovarian tumour models. This work is currently being translated into scale-up clinical manufacture systems. Our process provides a potentially near limitless, on-demand supply of standardized ‘off-the-shelf’ CAR-iNK cells, with potential application to a variety of cancers, sufficient to treat many patients using a single manufactured product.