WP5 will assess the therapeutic potential of radiopharmaceuticals on GIST by preliminary in vivo imaging studies using PET-CT. In comparison with the new radiotracers developed in WP4, two well-established molecules with high affinity for SST and GRP receptors will be tested. Minimally-invasive therapies will be tested preclinically and monitored by non-invasive diagnostics. An in silico PBPK model for the distribution of the tracers in humans will be developed based on the mouse data. Differences in biokinetics of tested substances will be described by PBPK modelling.
A standard procedure for radiolabelling with Ga-68 of peptides with high affinity for somatostatine (SST) and bombesin receptors was developed. The new strategy of direct labelling with Ga-68 acid solution getting from the 68Ge-68Ga generator avoids the laborious post-processing of the eluate and represents an important improvement in the labelling with Ga-68 in term of time of synthesis and quality of the radiopharmaceuticals. The strategy was already applied to the peptides DOTA-TATE and an antagonist of bombesin receptors and then the same procedure was tested by AAA and the University of Innsbruck (MUI) obtaining good results in term of radiolabelling yield and purity meeting the European Pharmacopoeia criteria.