A Novel Urine Exosome Gene Expression Assay to Predict High-grade Prostate Cancer at Initial Biopsy

Overdiagnosis and overtreatment of indolent prostate cancer (PCA) is a serious health issue in most developed countries. There is an unmet clinical need for noninvasive, easy to administer, diagnostic assays to help assess whether a prostate biopsy is warranted.

To determine the performance of a novel urine exosome gene expression assay (the ExoDx Prostate IntelliScore urine exosome assay) plus standard of care (SOC) (ie, prostate-specific antigen [PSA] level, age, race, and family history) vs SOC alone for discriminating between Gleason score (GS)7 and GS6 and benign disease on initial biopsy. DESIGN, SETTING, AND PARTICIPANTS: In training, using reverse-transcriptase polymerase chain reaction (PCR), we compared the urine exosome gene expression assay with biopsy outcomes in 499 patients with prostate-specific antigen (PSA) levels of 2 to 20 ng/mL. The derived prognostic score was then validated in 1064 patients from 22 community practice and academic urology clinic sites in the United States. Eligible participants included PCA-free men, 50 years or older, scheduled for an initial or repeated prostate needle biopsy due to suspicious digital rectal examination (DRE) findings and/or PSA levels (limit range, 2.0-20.0 ng/mL). MAIN OUTCOMES AND MEASURES: Evaluate the assay using the area under receiver operating characteristic curve (AUC) in discrimination of GS7 or greater from GS6 and benign disease on initial biopsy.