Table 8.

Summary of radiolabeled bombesin analogues for GRPR-positive tumor imaging over past 3 years.

Composition of Studied Compounds - Metal Radionuclide - BFCA - Linker - Peptide	Results and Findings - Phase of Trials - Cancer Type Studied - Imaging Technique Used - Benefits/Limitations/Conclusion	Reference
- 67Ga, 68Ga, 111In, 177Lu - DOTA - p-aminomethylaniline-diglycolic acid - NeoBOMB1	- preclinical in vitro, in vivo; clinical, 4 patients - prostate - PET/CT - [68Ga]Ga-NeoBOMB1 with preserved GRPR affinity, high in vivo stability, and high contrast image in patients	[152]
- 55Co, 57Co - NOTA - PEG2 - RM26	- preclinical in vitro, in vivo - prostate - SPECT/CT, PET/CT - favorable pharmacokinetics and 3-fold lower internalization of 55Co-labeled peptide compared to 111In-labeled conjugate making it potential “next day” high contrast PET imaging probe	[153]
- 64Cu - DOTA with hydroxamic acid arms (DOTHA2), NOTA - PEG - RM26	- preclinical in vitro, in vivo - prostate - microPET/CT - fast elimination and slightly better in vivo imaging properties for DOTHA2-conjugate than reference	[73]
- 64Cu - DOTA, NODAGA - [Pro-Gly]12 linker, PEG3 - RGD, BBN(7–14)	- preclinical in vitro, in vivo - prostate - microPET - NODAGA-conjugate for dual αvβ3/GRPR targeting with better pharmacokinetics than DOTA, but low tumor uptake in vivo	[74]
- 68Ga - DOTA - N-(γ-maleimidobutyryloxy) succinimide ester - PSMA, Lys3-BBN(1-14)	- preclinical in vitro, in vivo - pulmonary and prostate - microPET/CT - higher cell uptake and internalization, greater affinity for GRPR but lower for PSMA of dimer compared to single [68Ga]Ga-BBN/-PSMA monomers	[154]
- 68Ga - DOTA -4-amino-1-carboxymethylpiperidine - RM2	- clinical, 16 patients - prostate - PET/CT, multiparametric MRI - fusion of MRI and PET/CT improved detection of a primary disease, but expression of GRPR and PSMA was not correlated	[155]
- 68Ga - DOTA prepared from cyclen, DOTA-tris-(t-Bu) ester - x - BBN derivatives	- preclinical in vitro, in vivo - breast and prostate - preclinical nanoPET/CT - potency and efficiency of site-specific DOTA-cyclen comparable to that of DOTA-ester	[156]
- 99mTc - N4-chelator - PEG2-4 -D-Phe-Gln-Trp-Ala-Val-Gly-His-Leu-NH-CH2-CH3	- preclinical in vitro, in vivo - prostate - gamma counter - PEG spacer length with only little effect on GRPR affinity, tumor uptake and in vivo stability	[157]
- 44gSc, 68Ga - DOTA - aminovaleric acid -Gln7-Trp8-Ala9-Val10-Sar11-His12-FA0101013-Tle14-NH2	- preclinical in vitro, in vivo - prostate and breast cancer - PET/CT - 44gSc-conjugate with low uptake in breast cancer cells, but high tumor uptake and retention in prostate; differences in in vitro GRPR binding properties, but no in in vivo	[158]