Prostate Cancer Imaging Agents
Imaging agent	Targeting domain	Radiotracer	Current Status	Advantages	Disadvantages
7E11	Intracellular epitope of PSMA	111 In	pre-surgical staging and the evaluation of PSA relapse after local therapy	In pre-surgical patients with high- risk disease, but negative conventional imaging, capromab penditide was able to identify patients with occult local nodal disease.	Significant false negative rate in the setting of PSA relapse [23]. Varied amount of efficacy with an average sensitivity and specificity of 60% and 70% respectively [24]. Imaging has been associated to binding of mAb7E11 to a receptor located inside the PC cell. Thus, only non-viable cells bind mAb7E11, which limits its use as a good imaging agent [25].
Hu mAb J591	Extracellular domain of PSMA	111In, 90Y, 177Lu	PSMA-specific internalizing antibodies such as J591 and J415 are ideal mAbs for the development of novel therapeutic methods to target the delivery of beta-emitting radionuclides, which include 131In, 90Y, and 177Lu for the treatment of PSMA-positive tumors [27].	J591 is specific to external domain of PSMA, thus targeting viable tumor. These immunoconjugates are better candidates for both imaging and targeted therapy than are antibodies targeting PSMA internally.	Slow target recognition and background clearance in an appropriate timeframe for diagnostic imaging
mAb 3/A12 [28, 30]	Extracellular domain of PSMA	64Cu	microPET images of mice with PSMA-positive tumors revealed a high uptake of the mAbs 24 and 48 hrs. post infusion		No human data available
mAb 3/E7 [28]	Extracellular domain of PSMA	64Cu	microPET images of mice with PSMA-positive tumors revealed a high uptake of the mAbs 24 and 48 hrs. post infusion		No human data available
mAb 3/F11 [28]	Extracellular domain of PSMA	64Cu	microPET images of mice with PSMA-positive tumors revealed a high uptake of the mAbs 24 and 48 hrs. post infusion	Planar gamma- scintigraphic images obtained for xenografted model demonstrated targeting for PSMA positive tumors suggesting possible applications in imaging and for targeted radiation therapy	No human data available
N-[N-[(S)- 1,3- Dicarboxypr opyl]carbam oyl]-4- [18F]fluorob enzyl-L- cysteine (DCFBC) [34]	Small molecule inhibitor of enzymatic active site of extracellular domain of PSMA	18F	Toxicity studies are under way en route to clinical implementation	Suitable physical half-life It can be synthesized with relatively ease in reasonable radiochemical yield and specific radioactivity. Low deflourination.	High renal uptake
MIP-1072 & MIP-1095 [56]	Urea based small molecule inhibitor of enzymatic domain of PSMA	123I	Due to the high specificity of 123I-MIP-1072 for PC trials are underway to monitor tumor progression in patients before, during, and after chemotherapy.	Superior safety profile. Low radiation dose. Faster target detection with saturable and competitive binding	Renal toxicity
MIP-1404 & MIP-1405 [57]	Urea based small molecule inhibitor of enzymatic domain of PSMA	99Tc	99mTc-MIP-1404 has minimal activity in the bladder, further work is planned to correlate imaging findings with histopathology in patients with high risk clinically- localized PC.	Both agents cleared the blood rapidly with MIP-1404 demonstrating significantly lower urinary activity (7%) compared to MIP- 1405 (26%). More bone lesion detected as compared to bone scan	Renal toxicity