DAP10/DAP12 Fusion Polypeptides Adaptor-Based CAR Architecture for NKG2D-Targeted Solid Tumour Immunotherapy

This patent covers a class of fusion proteins that join the DAP10 and DAP12 signalling adaptors into a single polypeptide which, when co-expressed with NKG2D, forms a compact natural-receptor-based chimeric antigen receptor that provides both T-cell activation and co-stimulation through native components rather than the engineered single-chain CAR architecture.

The Problem

CAR-T cell therapy has transformed treatment of B-cell malignancies and multiple myeloma but has not yet translated into a comparable solid tumour breakthrough. The problem is target selection. Most solid tumour antigens are either intracellular (and so invisible to a surface-binding CAR) or shared with normal tissue at lower levels (creating on-target, off-tumour toxicity). NKG2D ligands are one of the few groups with genuine tumour selectivity: the eight stress-induced human NKG2D ligands (MICA, MICB, ULBP1 through 6) are aberrantly expressed on almost all tumour types and on tumour-associated stromal elements such as endothelium, regulatory T-cells, and myeloid-derived suppressor cells, but are largely absent from healthy tissue. NKG2D-targeted CARs have been developed by fusing NKG2D to CD3 zeta or to CD28 or 4-1BB co-stimulatory domains. These designs either rely on association with endogenous DAP10, force a non-natural CD28 or 4-1BB co-stimulus, or risk recruiting regulatory T cells through unwanted p56lck motifs. None of them delivers an NKG2D-driven receptor that uses the cell’s own signalling machinery for both activation and co-stimulation.

What This Invention Does

The invention provides a fusion polypeptide that joins, in a single polypeptide chain, a DAP10 adaptor sequence and a DAP12 adaptor sequence (with an optional linker and optional N-terminal and C-terminal tags). When expressed alongside NKG2D, the fusion polypeptide and NKG2D co-assemble in the plasma membrane through their complementary charged transmembrane residues to form a compact adaptor-based chimeric antigen receptor. DAP10 provides co-stimulation (signal 2) via the phosphatidylinositol 3-kinase pathway without the p56lck-binding motif that recruits regulatory T cells; DAP12 contributes an immunoreceptor tyrosine-based activation motif (ITAM) and provides activation (signal 1). Together, in a single fusion, they deliver the two signals needed for full T-cell activation while keeping the receptor compact and built on native adaptors. The patent claims the fusion polypeptide, encoding nucleic acids, expression vectors, host cells, methods of manufacture, and use in treating cancer. The application is a divisional of AU 2020352574, claiming priority from UK provisional application GB 1913697.7 filed 23 September 2019.

Key Features

• Fusion of DAP10 and DAP12 in one polypeptide. The two natural NKG2D adaptors are joined into one molecule, ensuring stoichiometric co-expression and forcing both signals into the same receptor complex.
• A-B-C-D-E modular formula. The patent specifies an N-terminus optional sequence, DAP10, optional linker, DAP12, and C-terminus optional sequence formula, providing a precise architecture and design space within which functional variants can be claimed.
• Native receptor topology. Because NKG2D itself recognises tumour-selective ligands and the fusion uses native adaptors, the resulting receptor more closely resembles a natural receptor complex than a single-chain CAR, potentially reducing the kinds of artefactual activation that have plagued engineered receptors.
• Solid tumour focus. The patent is explicitly positioned for solid tumour CAR development, the principal unmet need in cell therapy after the success of CD19 and BCMA-directed products in haematological malignancies.
• Carve-outs to delineate scope. The claims expressly carve out specific sequences disclosed in WO 2019/182425 (the Phio Pharmaceuticals / earlier work) so that the protection is targeted to the new fusion architecture rather than to incumbents.

Who Is Behind It?

The applicant is King’s College London. The named inventors are Professor John Maher, an academic CAR-T pioneer at King’s who leads the CAR Mechanics laboratory and has co-founded multiple cell therapy spin-outs, and Dr David Marc Davies. The Australian patent attorney is Madderns in Adelaide. The application is a divisional of AU 2020352574 (filed 23 September 2020), claiming priority from UK provisional application 1913697.7 filed 23 September 2019.

Why It Matters

NKG2D-targeted CAR-T and CAR-NK programs from Celyad Oncology, CytoMed, and academic centres including King’s are among the most advanced solid tumour cell therapy programs that have moved into the clinic. The compact NKG2D adaptor CAR architecture offers a path to second-generation NKG2D therapies with improved manufacturability and potentially better in vivo persistence and tumour control. Australian patent rights for King’s are commercially material for any licensing or spin-out deal, including Maher’s existing cell therapy companies, and they will shape whether Australian academic and biotech groups working on NKG2D solid tumour therapies can develop products without taking a licence. Australia has growing cell and gene therapy infrastructure through the Cell Therapies and the Peter MacCallum Cancer Centre, making patents like this directly relevant to the local translational pipeline.

Related Concepts

NKG2D adaptor CARs sit within the broader field of chimeric antigen receptor engineering, which has reshaped haematological cancer treatment via CD19- and BCMA-directed products and is now being pushed into solid tumours. Because NKG2D is naturally expressed on natural killer cells, related programs also explore CAR-NK platforms that use the same receptor biology.

The underlying chemistry is a fusion protein approach in which two native signalling adaptors are joined into one polypeptide, leveraging the body’s own machinery rather than synthetic single-chain CAR domains.

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AU 2026201858 was published in the Australian Official Journal of Patents on 2 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.