68GaDOTATATE lyophilized ready to use kit for PET imaging in pancreatic cancer murine model

1926 Objectives 68Ga-labelled somatostatin analogues have been increasingly used for PET imaging and early diagnosis of sstr-positive tumors. In particular 68GaDOTATATE is a somatostatin analogue that binds somatostatin receptors (sstr) overexpressed on neuroendocrine tumors (NETs) with extremely high affinity to sstr2 and it is a very promising agent for detection of sstr-expressing NETs. We produced a GMP-grade lyophilized kit to be reconstituted with the eluate of a commercial 68Ga generator to generate a PET product meeting the current European Monography specifications. We then explored the 68GaDOTATATE kit ability to detect tumor mass in a model of pancreatic cancer. Methods AR42J rat pancreatic tumor cells were subcutaneously inoculated in Athymic nude mice. When tumor mass reached 200-500 mm3, the GMP-grade lyophilized 68GaDOTATATE kit was reconstituted with an eluate of 68Ga obtained from a commercial generator. Then, PET scan and biodistribution were performed 30 minutes after radiotracer injection with a dynamic acquisition of 50 minutes. In parallel, some mice were used for organ biodistribution at 30’, 1 h, 2h and 4 h after radiotracer injection at gamma counter. Results 68GaDOTATATE lyophilized kit confirmed its ability to clearly detect tumor mass. A high tumor uptake was confirmed by gamma counting at all time points recorded. Tumor to kidney (1.5-1.9 for all time points) and tumor to blood (6.6, 19.1, 64.7 and 81.9 at 30min, 1h, 2h and 4h, respectively) ratios were in favor of a good diagnostic performance of the kit. Conclusions These findings show that 68GaDOTATATE lyophilized kit is a useful ready to use diagnostic tool and has a very good lesion diagnostic performance due to both favorable biodistribution and suitable signal in PET modality.