The evolution of receptor-targeted PET and research into PSMA-PET has significantly increased the detection of Prostate Cancer (Pca) and improved patient selection for treatment. 30-50% of men undergoing radical prostatectomy (RP) for PCa will fail treatment with a rising PSA (biochemical recurrence/BCR). Within this cohort, a proportion of men with BCR (PSA ≤1 ng/mL) are potentially curable with stereotactic radiotherapy. As a proliferative agent, PSMA has improved detection of aggressive disease but less so in detecting indolent disease. Factors including PSMA expression, low volume disease...

Four men post-RP demonstrated BCR with serial negative PSMA-PET (68Ga-PSMA-11). Traditionally used imaging modalities including Bone Scan, CT and in some cases, whole body MRI failed to identify sites of recurrence. Via the TGA Special Access Scheme, CLARITY Pharmaceuticals provided access to [64Cu]Cu-SAR-BBN. All patients received on average 200 MBq of [64Cu]Cu-SAR-BBN intravenously with 60 minutes for uptake. Patient were scanned at 60-180 minutes post-injection with arms up, from vertex to mid thighs and at each bed position for two minutes. A low dose CT...

The 4 cases have demonstrated various imaging modalities being unable to identify a source of biochemical recurrence. These patients demonstrated avid lesions with [64Cu]Cu-SAR-Bombesin PET-CT. Case 1: 74M, PCa, Previous RP 2012, Pelvic Radiotherapy 2018. BCR with PSA Doubling in 8 months 2, 6, 30 Negative Bone Scan, FDG, serial PSMA-PET and Whole Body MRI. Positive [64Cu]Cu-SAR-BBN: left cervical chain. Ultrasound guided biopsy=metastatic PCa Case 2: 72M, PCa, External beam radiotherapy 13 years ago. BCR with Rising PSA 0.01, 0.09, 0.16 Negative CT, FDG, PSMA-PET....

[64Cu]Cu-SAR-BBN has demonstrated diagnostic imaging potential in PSMA-negative PCa. Additionally, this case series highlights the theranostic potential of BBN. Further work in larger cohorts will be required to assess the suitability of GRPR targeting in molecular imaging and theranostics.

N. John: Nothing to disclose B. Ho: Nothing to disclose W. Counter: Nothing to disclose K. Marripudi: Nothing to disclose S. Sharma: Nothing to disclose A. Joshua: Nothing to disclose J. de Leon: Nothing to disclose A. Nguyen: Nothing to disclose L. Emmett: Nothing to disclose

Acknowledgements: CLARITY Pharmaceuticals for access to [64Cu]Cu-SAR-BBN. Contact: Prof Louise Emmett, [email protected]