[Ga]Ga-RAYZ-8009: A Glypican-3-Targeted Diagnostic Radiopharmaceutical for Hepatocellular Carcinoma Molecular Imaging-A First-in-Human Case Series.

To date, the imaging and diagnosis of hepatocellular carcinoma (HCC) rely on CT/MRI, which have well-known limitations. Glypican-3 (GPC3) is a cell surface receptor highly expressed by HCC but not by normal or cirrhotic liver tissue. Here we report initial clinical results of GPC3-targeted PET imaging with [Ga]Ga-DOTA-RYZ-GPC3 (RAYZ-8009), a peptide-based GPC3 ligand in patients with known or suspected HCC. [Ga]Ga-RAYZ-8009 was obtained after labeling the peptide precursor with Ga from a Ge/Ga generator and heating at 90°C for 10 min followed by sterile filtration. After administration of [Ga]Ga-RAYZ-8009, a dynamic or static PET/CT scan was acquired between 45 min and 4 h after administration. Radiotracer uptake was measured by SUVs for the following tissues: suspected or actual HCC or hepatoblastoma lesions, non-tumor-bearing liver, renal cortex, blood pool in the left ventricle, and gastric fundus. Additionally, tumor-to-healthy-liver ratios (TLRs) were calculated. Twenty-four patients (5 patients in the dynamic protocol; 19 patients in the static protocol) were scanned. No adverse events occurred. Two patients had no lesion detected and did not have HCC during follow-up. In total, 50 lesions were detected and analyzed. The mean SUV of these lesions was 19.6 (range, 2.7-95.3), and the mean SUV was 10.1 (range, 1.0-49.2) at approximately 60 min after administration. Uptake in non-tumor-bearing liver and blood pool rapidly decreased over time and became negligible 45 min after administration (mean SUV, <1.6), with a continuous decline to 4 h after administration (mean SUV, 1.0). The opposite was observed for HCC lesions, for which SUVs and TLRs continuously increased for up to 4 h after administration. In individual lesion analysis, TLR was the highest between 60 and 120 min after administration. Uptake in the gastric fundus gradually increased for up to 45 min (to an SUV of 31.3) and decreased gradually afterward. [Ga]Ga-RAYZ-8009 is safe and allows for high-contrast imaging of GPC3-positive HCC, with rapid clearance from most normal organs. Thereby, [Ga]Ga-RAYZ-8009 is promising for HCC diagnosis and staging. Further research is warranted.