68Ga-BNOTA-PRGD2 PET/CT in Diagnosis and Evaluation of Glioma

Integrin αvβ3 is an important member of integrin receptor family and expressed preferentially on various types of tumor cells and the activated endothelial cells of tumor angiogenesis, but not or very low on the quiescent vessel cells and other normal cells. Therefore, the integrin αvβ3 receptor is becoming a valuable target for diagnosis and response evaluation of malignant tumors. The tri-peptide sequence of arginine-glycine-aspartic acid (RGD) can specifically bind to the integrin αvβ3 receptor. Accordingly, a variety of radio-labeled RGD-based peptides have been developed for non-invasive imaging of integrin αvβ3 receptor expression via positron emission tomography (PET) or single photon emission computed tomography (SPECT). Among all RGD radiotracers, several PET imaging agents, including 18F-Galacto-RGD and 18F-AH111585, have been investigated in clinical trials for tumor diagnosis, and the results demonstrated that both radiotracers allowed the specific imaging of various types of tumors, and the tumor uptake correlated well with the expression of integrin αvβ3. Recently, serial RGD dimeric peptides with PEG linkers have been studied. The new types of RGD peptides showed much higher in vitro integrin αvβ3-binding affinity than the single RGD tri-peptide sequence, and importantly, they exhibited significantly increased tumor uptake and improved in vivo kinetics in animal models. As a representative, 68Ga-BNOTA-PRGD2 could be easily prepared and exhibited excellent in vivo behaviors in animal models. No adverse reactions have been observed in animal models to date. For the further interests in clinical translation of 68Ga-BNOTA-PRGD2, an open-label brain PET/CT study was designed to investigate the diagnostic performance and evaluation efficacy of 68Ga-BNOTA-PRGD2 in pre-surgery glioma patients.