Purpose

Prostate cancer (PC) remains the most-common non-cutaneous cancer diagnosed in American males, accounting for an estimated 174,560 estimated new cases and 31,620 estimated deaths in 2019. Up to 40% of the patients with prostate cancer develop biochemical recurrence within 10 years after initial treatment. Usually an increase of the prostate-specific antigen (PSA) llevel precedes a clinically detectable recurrence by months to years, and this is currently used as a screening test before and subsequent to treatment. However, disease advancement can be local, regional or systemic, and each has significantly different approaches to disease management. Unfortunately, PSA level does not differentiate between these disease stages. This phase 2-3 study explores the utility of radiolabel 68Ga-RM2, a 68-gallium (68Ga)-labeled gastrin-releasing peptide receptor (GRPr) antagonist, for positron emission tomography (PET) / magnetic resonance imaging (MRI) (collectively, PET/MRI) as a potential tool to help discriminate between disease stages in participants after treatment with surgery or radiation, who present persistently elevated PSA levels (ie, may have prostate cancer), but were negative for cancer with a diagnostic regular medical care computed tomography (CT) scan 68Ga-RM2 (BAY86-7548) is also identified as a synthetic bombesin receptor antagonist. PET/MRI is the collective result of 2 scan processes (PET and MRI ) conducted during the same scan procedure (ie, a combined scan). After a regular medical care computed tomography (CT) scan, participants will be scanned with 68Ga-RM2 PET/MRI scan procedure. PET/MRI is used to assess the location, size, and metabolic activity of a suspected tumor. The 68Ga-RM2 radiolabel consisted of a ligand (the synthetic bombesin receptor antagonist) and the radioisotope 68Ga. The RM2 ligand targets gastrin-releasing peptide receptors (GRPr), commonly expressed by prostate cancer cells, and the radioisotope distinguishes those cells from the background. The criteria for scan "positivity" will be, when compared to background level of the liver (control), the 68Ga signal is stronger (positive - malignant) or weaker (negative - benign). This study will assess how well 68Ga-RM2 works in detecting prostate cancer in patients with 68Ga-RM2 PET/MRI may be able to see smaller tumors than the standard of care contrast-enhanced CT or MRI scan.