Project: Development of labelled soluble T cell Receptors as diagnostic imaging agents for cancer and diabetes image-guided therapy

The Project aims to test the feasibility of a novel approach to in vivo medical imaging, initiating the development of services and products aimed at the global drug discovery industry, particularly in type I diabetes and oncology. Non-invasive in vivo imaging is an emerging field and has application in a number of medical market segments. It bridges the gap between preclinical and clinical research and can be used in exploratory research and model validation studies as well as for the study of dynamic biodistribution and biomarker validation. It is also used to assess the delivery, liberation, efficacy and safety of drugs, biologics, biopharmaceuticals, nanoparticles, biomaterials and stem cells._x000D__x000D_Cancer treatment is undergoing a paradigm shift with the inclusion of molecular targeted therapies into standard regimens. As therapies become more personal, there is an increasing need for biomarkers and diagnostics that can be used to determine whether or not an individual patient is likely to respond to a targeted drug._x000D__x000D_Soluble T cell Receptors (TCRs) are an entirely novel class of targeting agent for cancer and diabetes since they target antigens not accessible to monoclonal antibodies. T cell Receptors (TCRs) recognise disease-associated peptide epitopes presented on the cell surface by Class I HLA molecules. Immunocore Ltd has unique, proprietary technology to engineer soluble T cell Receptors with greatly enhanced affinity for target antigens, which it is using to develop anti-cancer and anti-diabetic therapeutic agents. SPECT imaging technology is the most sensitive method of imaging diseased tissue in animals and humans. Animascope has leading expertise in this recently developed approach. The Project aims to develop SPECT imaging agents based on radiolabelled TCRs. These would be far more sensitive than other imaging agents on the market or in development and would be applicable to a range of previously inaccessible disease targets._x000D__x000D_SPECT imaging of radiolabelled TCRs offers a completely new imaging modality for the diagnosis and treatment of serious diseases. SPECT-TCR would revolutionise diagnosis of diabetes at an early stage where there is currently no diagnostic agent available; current diagnosis relies on measurement of blood glucose levels which only rise relatively late in the disease, after destruction of approximately 90% of beta-cell mass. A diabetes SPECT- TCR would also facilitate disease monitoring since it could give a measure of reCOing beta-cell mass. SPECT-TCR imaging agents for cancer would permit diagnosis of tumours expressing a particular target antigen (where biopsy is impossible or difficult to perform) and can identify patients suitable for treatment with a TCR-based therapy. _x000D__x000D_In the Project, high affinity, soluble TCRs with suitable tags would be produced by Immunocore to allow attachment of SPECT labels. TCRs are produced by expression in E. coli bacteria as denatured polypeptides, followed by refolding of the alpha and beta chains; a cost-effective system that produces extremely pure, clinical grade material, which is important for specific targeting, to either tumours or beta cell, in patients. Animascope will label the TCRs with a radionucleotide suitable for SPECT imaging. The TCR-SPECT tracer proteins will be assessed in cancer cells and beta cells, in vitro using isolated cells and in vivo in mouse models by Animascope. In vitro targeting will be independently confirmed using microscopy with fluorescently tagged TCRs at Immunocore._x000D__x000D_The results of the project will include a murine Insulin-specific TCR labelled with a SPECT tracer that can be used to image beta cells in vivo and provide semi-quantitative measurement of the number of beta cells, and is expected to provide an accurate replacement for the current crude and time-consuming methods. This tracer could be rapidly commercialised by Animascope either as a service packaged with their current in vivo offer and by out-licensing to companies and academic institutions carrying out murine models of diabetes. If successful a human-specific agent will be developed using the same approach and would have additional application in clinical diagnosis of type I diabetes, where there is currently no efficient agent available neither to detect early or pre-disease stage nor to efficiently monitor disease progress._x000D__x000D_A second output will be a prototype human cancer-specific TCR labelled with a SPECT tracer. If successful, the portfolio could then be expanded with pre-clinical imaging agents suitable for cancer drug discovery, and then clinical imaging agents that could be used to stratify patients prior to clinical trials or treatment. These will have significantly longer development pathways because of the need for testing in clinical trials. Immunocore aims to develop “P diagnostics” for its TCR-based targeted cancer drugs.

Acronym	ANIDIAG (Reference Number: 6184)
Duration	03/01/2011 - 28/12/2011
Project Topic	Novel medical imaging agents, more sensitive than current market standards, will be created by combining Immunocore’s T cell receptor technology with Animascope’s expertise in pre-clinical imaging. The Project will establish the feasibility of this approach and develop the first prototypes.
Project Results (after finalisation)	The objectives of the project were to bring the proof of concept on the feasibility of using the soluble TCR technology (Immunocre Ltd) to develop new medical imaging agents in the fields of cancer and diabetes diagnosis. Following the completion of the consortium agreement, Immunocore synthetized and modified the molecules (TCR) so that they could be labeled and visualized in vivo by Animascope. The first batches were delivered in August 2011, and we initiated the first technical phase which consisted in the TCR radiolabeling optimization. This phase was achieved by the end of 2011. _x000D_- Cancer: we demonstrated the feasibility of using TCR as diagnostic tools in oncology. This demonstration was obtained with molecules targeting specific melanoma cancer antigens. Different types of tumors were implanted in immuno-deficient mice and were visualized by single photon emission computed tomography (SPECT) and by fluorescence molecular tomography (FMT). These results were presented at the latest world molecular imaging congress (WMIC2012, Dublin, 5-8th Sept - Poster P525). This first part of the project opens the way to new applications in the field of cancer, with access to previously unaccessible cancer therapeutic targets using in vivo imaging._x000D_- Diabetes: imaging the mass and function of pancreatic beta cells is one of the most challenging imaging field to study. The CO goal is to non invasively visualize 1 to 2 % of pancreatic cells with a lack of available specific targets. Immunocore's technology can help solving the second point. Our intent is to develop a specific beta cells imaging agent to evaluate the therapeutic efficacy of antidiabetic drugs focusing initially on the preclinical stage. We labeled insulin peptides targeting TCR and evaluated the targeting potency of the molecule in normal and diabetic mice using SPECT. In our experimental conditions, we did not demonstrate this feasibility. One of the reason might be a weak epitope presentation on the beta cells surface, and a high background. However, we decided to pursue this work after the completion of ANIDIAG and to look into ways of solving these experimental issues. We will also evaluate other molecules targeting different epitopes._x000D_
Network	Eurostars
Call	Eurostars Cut-Off 5

Project partner

Number	Name	Role	Country
2	Animascope SARL	Coordinator	France
2	Immunocore Ltd	Partner	United Kingdom