64Cu-SAR-BBN for Identification of Participants With Recurrence of Prostate Cancer (SABRE)

64Cu-SAR-BBN Positron Emission Tomography: A Phase 2 Study of Participants With PSMA-negative Biochemical Recurrence of Prostate Cancer

The aim of this study is to determine the safety and efficacy of 64Cu-SAR-BBN and determine the ability of 64Cu-SAR-BBN Positron emission tomography (PET)/computed tomography (CT) to correctly detect the recurrence of prostate cancer in participants with prostate-specific membrane antigen (PSMA)-negative biochemical recurrence of prostate cancer following definitive therapy.

Participants with biochemical evidence of recurrence of prostate cancer (PC) were evaluated with 64Cu-SAR-BBN PET/CT (Day 0 and Day 1) and by conventional methodologies up to 180 days later (e.g., histopathology/biopsy, conventional imaging, prostate specific antigen [PSA] reduction post focal salvage therapy or radiotherapy with no concomitant androgen deprivation therapy). Three independent, central readers blinded to the participant number, the time of the PET/CT scan, and the results of the conventional methodologies, assessed the 64Cu-SAR-BBN PET/CT. Three separate independent readers assessed the results of the conventional methodologies.

Inclusion Criteria:

1. At least 18 years of age.

2. Signed informed consent.

3. Life expectancy ≥ 12 weeks as determined by the Investigator.

4. Histologically confirmed adenocarcinoma of prostate per original diagnosis and completed subsequent definitive therapy.

5. Suspected recurrence of PC based on rising PSA after definitive therapy on the basis of:

   1. Post-radical prostatectomy: Detectable or rising PSA that is ≥ 0.2 ng/mL with a confirmatory PSA ≥ 0.2 ng/mL (per American Urological Association recommendation) or
   2. Post-radiation therapy, cryotherapy, or brachytherapy: Increase in PSA level that is elevated by ≥ 2 ng/mL above the nadir (per American Society for Therapeutic Radiology and Oncology-Phoenix consensus definition).

6. Negative or equivocal findings for PC on (1) approved PSMA PET and (2) anatomical imaging (CT and/or magnetic resonance imaging) and (3) if available, any other conventional imaging performed as part of routine standard of care imaging workup within 60 days prior to Day 0.

7. The Eastern Cooperative Oncology performance status 0-2.

8. Adequate recovery from acute toxic effects of any prior therapy.

9. Estimated Glomerular Filtration Rate of 30 mL/min or higher.

10. Adequate liver function.

11. For participants who have partners of childbearing potential: Partner and/or participant must use a method of birth control with adequate barrier protection.

Exclusion Criteria:

1. Participants who received other investigational agents within 28 days prior to Day 0.
2. Participants administered any high energy (>300 kiloelectronvolts (keV)) gamma-emitting radioisotope within 5 physical half-lives prior to Day 0.
3. Ongoing treatment or treatment within 90 days of Day 0 with any systemic therapy (e.g. androgen-deprivation therapy, antiandrogen, gonadotropin-releasing hormone, luteinizing hormone-releasing hormone agonist or antagonist) for PC.
4. Participants who are known to require prohibited treatment (e.g., initiation of androgen-deprivation therapy due to rapidly rising PSA) before the 64Cu-SAR-BBN PET/CT results can be verified via histopathology or follow-up imaging.
5. Known or expected hypersensitivity to 64Cu-SAR-BBN or any of its components.
6. Any serious medical condition or extenuating circumstance which the investigator feels may interfere with the procedures or evaluations of the study.