First in Human Evaluation and Dosimetry Calculations for Peptide 124I-p5+14—a Novel Radiotracer for the Detection of Systemic Amyloidosis Using PET/CT Imaging

Autor: Ronald H. Lands, Michael G. Stabin, Dustin Powell, Bryan Whittle, Aaron Endsley, Alan Stuckey, Ryan R. Julian, Tyler R. Lambeth, Emily B. Martin, Stephen J. Kennel, Angela Williams, Jonathan S. Wall, Sarah Hall
Rok vydání: 2021
Předmět:
Zdroj: Molecular Imaging and Biology. 24:479-488
ISSN: 1860-2002
1536-1632
DOI: 10.1007/s11307-021-01681-2
Popis: Purpose Accurate diagnosis of amyloidosis remains a significant clinical challenge and unmet need for patients. The amyloid-reactive peptide p5+14 radiolabeled with iodine-124 has been developed for the detection of amyloid by PET/CT imaging. In a first-in-human evaluation, the dosimetry and tissue distribution of 124I-p5+14 peptide in patients with systemic amyloidosis. Herein, we report the dosimetry and dynamic distribution in the first three enrolled patients with light chain-associated (AL) amyloidosis. Procedures The radiotracer was assessed in a single-site, open-label phase 1 study (NCT03678259). The first three patients received a single intravenous infusion of 124I-p5+14 peptide (≤37 MBq). Serial PET/CT imaging was performed during the 48 h post-infusion. Dosimetry was determined as a primary endpoint for each patient and gender-averaged mean values were calculated. Pharmacokinetic parameters were estimated from whole blood radioactivity measurements and organ-based time activity data. Lastly, the biodistribution of radiotracer in major organs was assessed visually and compared to clinically appreciated organ involvement. Results Infusion of the 124I-p5+14 was well tolerated with rapid uptake in the heart, kidneys, liver, spleen, pancreas, and lung. The gender-averaged whole-body effective radiation dose was estimated to be 0.23 (± 0.02) mSv/MBq with elimination of the radioactivity via renal and gastrointestinal routes. The whole blood elimination t1/2 of 21.9 ± 7.6 h. Organ-based activity concentration measurements indicated that AUClast tissue:blood ratios generally correlated with the anticipated presence of amyloid. Peptide uptake was observed in 4/5 clinically suspected organs, as noted in the medical record, as well as six anatomic sites generally associated with amyloidosis in this population. Conclusion Peptide 124I-p5+14 rapidly distributes to anatomic sites consistent with the presence of amyloid in patients with systemic AL. The dosimetry estimates established in this cohort are acceptable for whole-body PET/CT imaging. Pharmacokinetic parameters are heterogeneous and consistent with uptake of the tracer in an amyloid compartment. PET/CT imaging of 124I-p5+14 may facilitate non-invasive detection of amyloid in multiple organ systems.
Databáze: OpenAIRE
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