A Pilot Comparison of 68Ga-P16-093 and 18F-FDG PET/CT Imaging in the Same Group of Clear Cell Renal Cell Carcinoma Patients

Renal cell carcinoma (RCC) is the most common solid tumor within the kidney and accounts for approximately 3% of all malignancies in the world. Clear cell RCC (ccRCC) is the most common subtype and accounts for the majority of kidney cancer-related deaths. Importantly, pro-angiogenic factors (VEGF, PDGF) are strongly upregulated in clear cell RCC, leading to high vascularized tumors. Prostate-specific membrane antigen (PSMA), as known as folate hydrolase I or glutamate carboxypeptidase II, is overexpressed on the cells of prostatic adenocarcinoma. However, PSMA is also expressed by tumor cells or neovascular endothelial cells of various solid neoplasms, such as renal cell carcinoma. Therefore, PSMA may be an ideal target for the diagnosis of ccRCC. 68Ga-P16-093, a novel radiopharmaceutical targeting PSMA, with the urea fragment of a conjugate that employs the HBED-CC chelator for labeling with 68Ga(III). The HBED-based chelating ligand binds the 68Ga3+ ion with high affinity in a pseudo-octahedral N2O4 coordination sphere by its two phenolate O, two amino-acetate carboxylate O, and two amino N donor atoms. This pilot study was designed to evaluate the diagnostic performance of 68Ga-P16-093 in the same group of ccRCC patients, compared with 18F-FDG PET/CT.