Until recently, there’s been scarce overlap between the NK cell field and the world of checkpoint inhibitors, with the former focused on cell therapies to kill tumor cells directly and the latter on relieving immune suppression of T cells. But a new class of checkpoint inhibitors is growing that sits at the intersection of those fields, with the potential to harness both mechanisms to produce more potent immunotherapies.
Two companies are leading the way, Innate Pharma S.A. and Oxford BioTherapeutics Ltd., building pipelines on the strategy that the intersection of NK cells and checkpoint inhibition can mix the benefits of both.
Companies developing checkpoint inhibitors for cancer have chiefly focused on activation of T cells, because they kill tumor cells in a selective fashion through recognition of tumor antigens. T cells are also long-lived, and remain ready to strike if the tumor antigen shows up again.
NK cells also kill tumors, though they recognize them via a different mechanism. Most commercial activity has centered on using the cells directly as autologous or allogeneic therapies.
However, like T cells, NK cells express checkpoint receptors that tumors use to prevent them from mounting an immune attack.
Most checkpoint proteins on NK cells are enriched on the cell type rather than specific to them, and are also found on T cells.
According to Christian Rohlff, CEO of Oxford BioTherapeutics, finding the targets with the highest expression on NK cells and cytotoxic T cell subsets, and the lowest expression on other types of immune and non-immune cells, could solve two of the biggest problems with