First-in-Humans Trial of Dasatinib-Derivative Tracer for Tumor Kinase-Targeted PET.

Abstract

We developed a first-of-kind dasatinib-derivative imaging agent, 18F-SKI-249380 (18F-SKI), and validated its use for noninvasive in vivo tyrosine kinase-targeted tumor detection in preclinical models. In this study, we assessed the feasibility of using 18F-SKI for PET imaging in patients with malignancies. Methods: Five patients with a prior diagnosis of breast cancer, renal cell cancer, or leukemia underwent whole-body PET/CT imaging 90 min after injection of 18F-SKI (mean, 241.24 ± 116.36 MBq) as part of a prospective study. In addition, patients underwent either a 30-min dynamic scan of the upper abdomen including, at least partly, cardiac left ventricle, liver, spleen, and kidney (n = 2) or three 10-min whole-body PET/CT scans (n = 3) immediately after injection and blood-based radioactivity measurements to determine the time course of tracer distribution and facilitate radiation dose estimates. A subset of 3 patients had a delayed whole-body PET/CT scan at 180 min. Biodistribution, dosimetry, and tumor uptake were quantified. Absorbed doses were calculated using OLINDA/EXM 1.0. Results: No adverse events occurred after injection of 18F-SKI. In total, 27 tumor lesions were analyzed, with a median SUVpeak of 1.4 (range, 0.7-2.3) and tumor-to-blood ratios of 1.6 (range, 0.8-2.5) at 90 min after injection. The intratumoral drug concentrations calculated for 4 reference lesions ranged from 0.03 to 0.07 nM. In all reference lesions, constant tracer accumulation was observed between 30 and 90 min after injection. A blood radioassay indicated that radiotracer clearance from blood and plasma was initially rapid (blood half-time, 1.31 ± 0.81 min; plasma, 1.07 ± 0.66 min; n = 4), followed variably by either a prolonged terminal phase (blood half-time, 285 ± 148.49 min; plasma, 240 ± 84.85 min; n = 2) or a small rise to a plateau (n = 2). Like dasatinib, 18F-SKI underwent extensive metabolism after administration, as evidenced by metabolite analysis. Radioactivity was predominantly cleared via the hepatobiliary route. The highest absorbed dose estimates (mGy/MBq) in normal tissues were to the right colon (0.167 ± 0.04) and small intestine (0.153 ± 0.03). The effective dose was 0.0258 mSv/MBq (SD, 0.0034 mSv/MBq). Conclusion:18F-SKI demonstrated significant tumor uptake, distinct image contrast despite low injected doses, and rapid clearance from blood.

• Authors: Simone Krebs, Darren R Veach, Lukas M Carter, Milan Grkovski, Monica Fornier, Michael J Mauro, Martin H Voss, Daniel C Danila, Eva Burnazi, Manda Null, Kevin Staton, Christina Pressl, Bradley J Beattie, Pat Zanzonico, Wolfgang A Weber, Serge K Lyashchenko, Jason S Lewis, Steven M Larson, Mark P S Dunphy
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 61 Issue 11 Pg. 1580-1587 (11 2020) ISSN: 1535-5667 [Electronic] United States
• PMID: 32169913 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: © 2020 by the Society of Nuclear Medicine and Molecular Imaging.

Chemical References

• Fluorine Radioisotopes
• Radiopharmaceuticals
• Protein-Tyrosine Kinases
• Dasatinib

Topics

• Aged
• Dasatinib (analogs & derivatives)
• Female
• Fluorine Radioisotopes (pharmacokinetics)
• Humans
• Male
• Middle Aged
• Neoplasms (diagnostic imaging)
• Pilot Projects
• Positron Emission Tomography Computed Tomography (methods)
• Prospective Studies
• Protein-Tyrosine Kinases (metabolism)
• Radiopharmaceuticals (pharmacokinetics)
• Whole Body Imaging