Olof Eriksson1,2, Irina Velikyan3,4, Torsten Haack5, Martin Bossart5, Iina Laitinen6, Philip J Larsen5, Jan Erik Berglund7, Gunnar Antoni3,4, Lars Johansson1, Stefan Pierrou1, Joachim Tillner8, Michael Wagner9. 1. Antaros Medical AB, Uppsala, Sweden. 2. Science for Life Laboratory, Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden. 3. Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden. 4. Akademiska Sjukhuset, Uppsala, Sweden. 5. R&D Research Platform, Integrated Drug Discovery, Sanofi, Frankfurt, Germany. 6. Global Imaging, Sanofi, Frankfurt, Germany. 7. Clinical Trial Consultants AB, Uppsala, Sweden; and. 8. Translational Medicine, Sanofi, Frankfurt, Germany. 9. R&D Research Platform, Integrated Drug Discovery, Sanofi, Frankfurt, Germany Michael.Wagner@sanofi.com.
Abstract
Despite the importance of the glucagon receptor (GCGR) in disease and in pharmaceutical drug development, there is a lack of specific and sensitive biomarkers of its activation in humans. The PET radioligand 68Ga-DO3A-VS-Tuna-2 (68Ga-Tuna-2) was developed to yield a noninvasive imaging marker for GCGR target distribution and drug target engagement in humans. Methods: The biodistribution and dosimetry of 68Ga-Tuna-2 was assessed by PET/CT in 13 individuals with type 2 diabetes as part of a clinical study assessing the occupancy of the dual GCGR/glucagon like peptide-1 receptor agonist SAR425899. Binding of 68Ga-Tuna-2 in liver and reference tissues was evaluated and correlated to biometrics (e.g., weight or body mass index) or other biomarkers (e.g., plasma glucagon levels). Results: 68Ga-Tuna-2 binding was seen primarily in the liver, which is in line with the strong expression of GCGR on hepatocytes. The kidneys demonstrated high excretion-related retention, whereas all other tissue demonstrated rapid washout. The SUV55 min (SUV during the last 10-min time frame, 50-60 min after administration) uptake endpoint was sensitive to endogenous levels of glucagon. 68Ga-Tuna-2 exhibited a safe dosimetry profile and no adverse events after intravenous administration. Conclusion: 68Ga-Tuna-2 can be used for safe and accurate assessment of the GCGR in human. It may serve as an important tool in understanding the in vivo pharmacology of novel drugs engaging the GCGR.
Despite the importance of the glucagon receptor (GCGR) in disease and in pharmaceutical drug development, there is a lack of specific and sensitive biomarkers of its activation in humans. The PET radioligand 68Ga-DO3A-VS-Tuna-2 (68Ga-Tuna-2) was developed to yield a noninvasive imaging marker for GCGR target distribution and drug target engagement in humans. Methods: The biodistribution and dosimetry of 68Ga-Tuna-2 was assessed by PET/CT in 13 individuals with type 2 diabetes as part of a clinical study assessing the occupancy of the dual GCGR/glucagon like peptide-1 receptor agonist SAR425899. Binding of 68Ga-Tuna-2 in liver and reference tissues was evaluated and correlated to biometrics (e.g., weight or body mass index) or other biomarkers (e.g., plasma glucagon levels). Results: 68Ga-Tuna-2 binding was seen primarily in the liver, which is in line with the strong expression of GCGR on hepatocytes. The kidneys demonstrated high excretion-related retention, whereas all other tissue demonstrated rapid washout. The SUV55 min (SUV during the last 10-min time frame, 50-60 min after administration) uptake endpoint was sensitive to endogenous levels of glucagon. 68Ga-Tuna-2 exhibited a safe dosimetry profile and no adverse events after intravenous administration. Conclusion: 68Ga-Tuna-2 can be used for safe and accurate assessment of the GCGR in human. It may serve as an important tool in understanding the in vivo pharmacology of novel drugs engaging the GCGR.
Authors: Olof Eriksson; Irina Velikyan; Torsten Haack; Martin Bossart; Iina Laitinen; Philip J Larsen; Jan Erik Berglund; Gunnar Antoni; Lars Johansson; Stefan Pierrou; Joachim Tillner; Michael Wagner Journal: J Nucl Med Date: 2021-09-09 Impact factor: 10.057