Biodistribution and Uptake of [68Ga]Ga-RAYZ-8009 in HCC Lesions and Comparison to Cross Sectional Imaging

Ziel/Aim: To date, the imaging and diagnosis of HCC rely on CT/MRI, which have well-known limitations. Glypican-3 (GPC3) is a membrane-associated proteoglycan which is highly overregulated in HCC. Here, we report initial clinical results of GPC3-targeted PET imaging with [⁶⁸Ga]Ga-RAYZ-8009, a peptide-based GPC3 ligand, in patients with known HCC intended for SIRT.

Methodik/Methods: [⁶⁸Ga]Ga-RAYZ-8009 was obtained by labeling the peptide precursor with ⁶⁸Ga from a ⁶⁸Ge/⁶⁸Ga generator using a Modular-Lab eazy radiosynthesizer. PET/CT scans were performed approximately 60 min after IV administration. Radiotracer uptake was measured by SUVs in the muscle, bone, blood pool, kidneys, tracer retention in the urinary bladder, stomach, liver and intrahepatic lesions with uptake higher than liver background. Up to five lesions per patient were classified in CT and/or MRI using LI-RADS. Additionally, tumor-to-liver-background ratios (TBRs) were calculated using SUVmax and SUVmean (defined on 50%-isocontour-VOIs).

Ergebnisse/Results: 9 patients with HCC intended for SIRT were included in the retrospective analysis. Median SUVmean (range) were 0.8 (0.3-1.4), 0.7 (0.4-09), 2.0 (1.3-3.7), 1.4 (0.9-3.8), 17 (12-39), 76 (36-148) and 23 (11-34) for muscle, bone, blood pool, liver, kidneys, tracer retention in the urinary bladder and stomach, respectively. Corresponding median SUVmax (range) were 1.2 (0.5-2.4), 1.0 (0.5-1.4), 3.1 (1.9-5.2), 2.4 (1.4-7.3), 26 (17-55), 97 (43-190) and 34 (18-56).

Lesions rated as LI-RADS 5 (n=8) showed a median TBRmax (range) of 16 (1.4-31), and median TBRmean (range) of 17 (1.4-36). Three MR-LI-RADS 5 lesions which were CT-LI-RADS≤3 were invisible in PET.

Lesions rated as LI-RADS 4 (n=7) showed a median TBRmax (range) of 14 (3.4-43), and median TBRmean (range) of 15 (3.3-45). Two MR LI-RADS-4 lesions were invisible in CT and PET.

Four additional lesions were detected in PET which were not visible on CT/MRI (median TBRmax was 6.5 and TBRmean 7.1).

Schlussfolgerungen/Conclusions: [⁶⁸Ga]Ga-RAYZ-8009 shows favorable biodistribution with minimal background uptake except in the stomach and high contrast of intrahepatic HCC lesions, with the highest uptake observed in LI-RADS 5 lesions. Thereby, [⁶⁸Ga]Ga-RAYZ-8009 is promising for HCC diagnosis and staging. Correlation with follow-up imaging of lesions is planned.

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Artikel online veröffentlicht:
12. März 2025