Abstract
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Introduction: [18F]SiFAlin-TATE, a novel somatostatin receptor (SST) targeting peptide for the diagnosis of well-differentiated neuroendocrine tumors (NET) using positron emission tomography/computed tomography (PET/CT), holds promise to have superior characteristics over the current clinical reference standard [68Ga]Ga-DOTA-TOC accompanied by economic and logistic advantages. Herein, we present the translation of [18F]SiFAlin-TATE into the clinical environment, including first in-human data and comprehensive aspects of synthesis, quality control and automation.
Methods: The synthesis of [18F]SiFAlin-TATE was translated to the clinical environment and adapted to meet all quality control specifications. Thirteen patients with NET were scanned with [68Ga]Ga-DOTA-TOC and [18F]SiFAlin-TATE (median interval 8 months, range 3-26 months). Normal organ biodistribution and tumor uptake of NET lesions were compared by SUVmean and SUVmax measurements and calculation of tumor-to-liver (TLR) and tumor-to-spleen (TSR) ratios. Automated production of [18F]SiFAlin-TATE was developed and exemplified on a novel lab on chip system.
Results: The radiolabeled product was obtained in 42 ± 3% (n = 6) d.c. radiochemical yield, with a radiochemical purity of >97% and a molar activity of 60 ± 7 GBq/µmol (n = 6). The synthesis time was ~25 to 30 minutes. Quality control measurements always met the local release criteria. Compared to [68Ga]Ga-DOTA-TOC, tumor uptake of [18F]SiFAlin-TATE was significantly higher in common metastatic sites of NET including the liver (SUVmax 18.8 ± 8.4 vs. 12.8 ± 5.6; p < 0.001), lymph nodes (SUVmax 23.8 ± 20.7 vs. 17.4 ± 16.1; p < 0.001) and bone (SUVmax 16.0 ± 10.1 vs. 10.3 ± 5.7; p < 0.01) resulting in favorable TLR and TSR ratios. Biodistribution data revealed a slightly higher uptake of [18F]SiFAlin-TATE in liver, spleen and adrenal glands, and a significantly higher uptake in the liver. The new type of radiopharmaceutical production using an innovative lab on chip platform proved suitable for the automated manufacture of [18F]SiFAlin-TATE.
Conclusions: [18F]SiFAlin-TATE shows promising clinical data and favorable imaging characteristics for the diagnosis of NETs using PET/CT. The simple and fast labeling procedure in combination with economic and logistic advantages of 18F- vs 68Ga-labelled compounds are beneficial for a future implementation of [18F]SiFAlin-TATE into the clinical routine. Acknowledgements:The lab on chip platform was made available by GE Healthcare, which is gratefully acknowledged.