New gallium-68 complexes for PET imaging of aggrecans – ImAgGa

The ImAgGa project consists in developing a new gallium-68 radiotracer highly specific to articular cartilage proteoglycan aggrecan. This new complex will allow early diagnosis and quantification of osteoarthritis as well as its longitudinal follow-up by PET imaging. Such a tool is essential for the evaluation of Disease-Modifying OsteoArthritis Drugs (DMOADs) that are under development. The synthesis of several kind of bifunctionalized ligand structures will be undertaken. The best radiotracer will be selected according to criteria such as effective radiolabeling, stability of the complex in plasma and/or serum, binding affinity of the complexes toward aggrecans (determination of Kd by MicroScaleThermophoresis), biodistribution in an healthy animal model (i.e. high cartilage-specific binding). The selected compound will then be evaluated in preclinical studies on an osteoarthritic animal model treated or not with a promising DMOAD. Lastly, a dosimetric study and development of a radiolabeling kit will be carried out.