TY - JOUR T1 - <sup>18</sup>F-Labeled Bombesin Analog for Specific and Effective Targeting of Prostate Tumors Expressing Gastrin-Releasing Peptide Receptors JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 270 LP - 278 DO - 10.2967/jnumed.110.081620 VL - 52 IS - 2 AU - Michael Honer AU - Linjing Mu AU - Timo Stellfeld AU - Keith Graham AU - Miljen Martic AU - Cindy R. Fischer AU - Lutz Lehmann AU - Pius A. Schubiger AU - Simon M. Ametamey AU - Ludger Dinkelborg AU - Ananth Srinivasan AU - Sandra Borkowski Y1 - 2011/02/01 UR - http://jnm.snmjournals.org/content/52/2/270.abstract N2 - Bombesin is a peptide exhibiting high affinity for the gastrin-releasing peptide receptor (GRPr), which is highly overexpressed on prostate cancer cells. In the present study, we developed an 18F-labeled bombesin analog, 18F-BAY 86-4367, which is currently being clinically tested for use in PET of prostate cancer. Methods: In vitro pharmacologic studies were performed to characterize the nonradioactive (19F) standard of the bombesin analog for binding affinity and selectivity for GRPr. The stability of 18F-BAY 86-4367 was determined in murine and human plasma. In vivo, the tumor-targeting potential and pharmacokinetic profile of the 18F tracer were analyzed with biodistribution experiments and PET studies of prostate tumor–bearing mice. Results: The nonradioactive (19F) standard of the bombesin analog showed subnanomolar and GRPr-selective binding affinity. The stability of the tracer in murine and human plasma was found to be high. In 2 prostate cancer xenograft models (PC-3 and LNCaP), 18F-BAY 86-4367 showed more specific and effective GRPr-based targeting in vivo than the benchmark radiotracers 18F-fluoroethylcholine and 18F-FDG. In addition, rapid tumor targeting and fast renal excretion (∼70%) and hepatobiliary excretion (∼10%) were identified in both xenograft models. Furthermore, PET studies provided clear and specific visualization of PC-3 tumors in mice. Conclusion: Favorable preclinical data showing specific and effective tumor targeting by 18F-BAY 86-4367 suggest that a clinical trial be undertaken to test its diagnostic utility in PET for prostate carcinoma patients. ER -