Introduction:

The ExoDx^TM Prostate Test (ExoDx) is a unique genomic urine liquid biomarker test that can be collected at home or in office to inform initial and repeat prostate biopsy decisions. The test was validated in multiple prospective multi-center trials. ^1-3

For men on Active Surveillance (AS) protocols, NCCN recommends a repeat confirmatory biopsy and mpMRI no more often than every 12 months, unless clinically indicated. The guidelines acknowledge that a negative mpMRI does not exclude the possibility of prostate cancer, and biomarkers should be considered in the decision process to biopsy this population. ^{4, 5} Biomarkers may provide an orthogonal risk assessment and complementary information for the biopsy decision. ⁶

The ExoDx test cut-point was developed for men being considered for an initial or repeat biopsy. In this study we evaluate the existing 15.6 cut-point for men enrolled in AS protocols and examine the benefit of incorporating the ExoDx Prostate biomarker test in an AS setting.

Methods:

Patients with Grade Group 1 (GG1) on a diagnostic biopsy consented to provide a urine sample within a month prior to a subsequent confirmatory biopsy. The clinical data captured included demographics, PSA, DRE, mpMRI, and pathology data from both diagnostic and confirmatory biopsies. An interim analysis was performed on 182 patients with enrollment currently on-going. Metrics were calculated based on the highest GG between the diagnostic and confirmatory biopsies.

Results:

In this cohort (n=182), 37.4% upgraded from GG1 to GG2 and higher. When evaluated independently, the ExoDx test (at the validated cut-point of 15.6), and mpMRI performed similarly with NPVs of 80.0% vs 77.5%, respectively. In a subset of men with PIRADS 1 & 2, the NPV for the ExoDx test was 100% (Table 1). Similar performance metrics are also seen in PIRADS 3.

Conclusion:

Based on these interim results, the ExoDx^TM Prostate Test is valuable both as a standalone tool and when utilized alongside mpMRI to reduce unnecessary procedures and improve management decisions for men on AS. Also, test utilization provides an objective risk assessment and easy access for men considering AS protocols.

Funding: Exosome Dx