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Mol Imaging Biol. 2017 Oct;19(5):779-786. doi: 10.1007/s11307-017-1064-z.

Radiosynthesis and First-In-Human PET/MRI Evaluation with Clinical-Grade [18F]FTC-146.

Author information

1
Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA.
2
Department of Diagnostic Physics, Oslo University Hospital, Oslo, Norway.
3
The Norwegian Medical Cyclotron Centre, Oslo, Norway.
4
Radiological Sciences Laboratory, Department of Radiology, Stanford University, Stanford, CA, 94305, USA.
5
Department of Pharmaceutics, P1-27, University of Florida, Gainesville, FL, 32610, USA.
6
Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, USA.
7
Department of Radiology and Molecular Imaging Program at Stanford (MIPS), Stanford University School of Medicine, 300 Pasteur Drive S-068B, Stanford, CA, 94305, USA. biswal@stanford.edu.
8
Molecular Imaging Program at Stanford (MIPS), Departments of Radiology and Bioengineering, Bio-X Program, Stanford University School of Medicine, 1201 Welch Road, PS049, Stanford, CA, 94305-5484, USA. chinf@stanford.edu.

Abstract

PURPOSE:

Sigma-1 receptors (S1Rs) play an important role in many neurological disorders. Simultaneous positron emission tomography (PET)/magnetic resonance imaging (MRI) with S1R radioligands may provide valuable information for diagnosing and guiding treatment for these diseases. Our previously reported S1R radioligand, [18F]FTC-146, demonstrated high affinity for the S1R (K i = 0.0025 nM) and excellent selectivity for the S1R over the sigma-2 receptor (S2Rs; K i = 364 nM) across several species (from mouse to non-human primate). Herein, we report the clinical-grade radiochemistry filed with exploratory Investigational New Drug (eIND) and first-in-human PET/MRI evaluation of [18F]FTC-146.

PROCEDURES:

[18F]FTC-146 is prepared via a direct [18F] fluoride nucleophilic radiolabeling reaction and formulated in 0.9 % NaCl containing no more than 10 % ethanol through sterile filtration. Quality control (QC) was performed based on USP 823 before doses were released for clinical use. The safety and whole body biodistribution of [18F]FTC-146 were evaluated using a simultaneous PET/MR scanner in two representative healthy human subjects.

RESULTS:

[18F]FTC-146 was synthesized with a radiochemical yield of 3.3 ± 0.7 % and specific radioactivity of 8.3 ± 3.3 Ci/μmol (n = 10, decay corrected to EOB). Both radiochemical and chemical purities were >95 %; the prepared doses were stable for 4 h at ambient temperature. All QC test results met specified clinical criteria. The in vivo PET/MRI investigations showed that [18F]FTC-146 rapidly crossed the blood brain barrier and accumulated in S1R-rich regions of the brain. There were also radioactivity distributed in the peripheral organs, i.e., the lungs, spleen, pancreas, and thyroid. Furthermore, insignificant uptake of [18F]FTC-146 was observed in cortical bone and muscle.

CONCLUSION:

A reliable and automated radiosynthesis for providing routine clinical-grade [18F]FTC-146 for human studies was established in a modified GE TRACERlab FXFN. PET/MRI demonstrated the initial tracer biodistribution in humans, and clinical studies investigating different S1R-related diseases are in progress.

KEYWORDS:

Automated radiosynthesis; Clinical; PET/MRI; Radiopharmaceuticals; [18F]FTC-146; sigma-1 receptor

PMID:
28280965
DOI:
10.1007/s11307-017-1064-z
[Indexed for MEDLINE]

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