Value of [68Ga]Ga-NYM046 PET/CT, in Comparison with 18F-FDG PET/CT, for Diagnosis of Clear Cell Renal Cell Carcinoma.

This study aimed to investigate the diagnostic efficacy of [68Ga]Ga-NYM046 PET/CT in animal models and patients with clear cell renal cell carcinoma (ccRCC) and to compare its performance with that of 18F-FDG PET/CT.

Methods: The in vivo biodistribution of [68Ga]Ga-NYM046 was evaluated in mice bearing OS-RC-2 xenografts. Twelve patients with ccRCC were included in the study; all completed paired [68Ga]Ga-NYM046 PET/CT and 18F-FDG PET/CT. The diagnostic efficacies of these 2 PET tracers were compared. Moreover, the positive rate of carbonic anhydrase IX in the pathologic tissue sections was compared with the SUVmax obtained by PET/CT.

Results: The tumor accumulation of [68Ga]Ga-NYM046 at 1 h after injection in OS-RC-2 xenograft tumor models was 7.21 ± 2.39 injected dose per gram of tissue. Apart from tumors, the kidney and stomach showed high-uptake distributions. In total, 9 primary tumors, 96 involved lymph nodes, and 147 distant metastases in 12 patients were evaluated using [68Ga]Ga-NYM046 and 18F-FDG PET/CT. Compared with 18F-FDG PET/CT, [68Ga]Ga-NYM046 PET/CT detected more primary tumors (9 vs. 1), involved lymph nodes (95 vs. 92), and distant metastases (137 vs. 127). In quantitative analysis, the primary tumors' SUVmax (median, 13.5 vs. 2.4; z = -2.668, P = 0.008) was significantly higher in [68Ga]Ga-NYM046 PET/CT. Conversely, the involved lymph nodes' SUVmax (median, 5.9 vs. 7.6; z = -3.236, P = 0.001) was higher in 18F-FDG PET/CT. No significant differences were found for distant metastases (median SUVmax, 5.0 vs. 5.0; z = -0.381, P = 0.703). Higher [68Ga]Ga-NYM046 uptake in primary tumors corresponded to higher expression of carbonic anhydrase IX, with an R 2 value of 0.8274.

Conclusion: [68Ga]Ga-NYM046 PET/CT offers a viable strategy for detecting primary tumors, involved lymph nodes, and distant metastases in patients with ccRCC.