Prostate Cancer Risk Identification in a Multi-Ethnic Cohort: a Prospective US-based Multi-center Validation Study of Proclarix

Overview

The study is a prospective, multi-center, single cohort study involving up to 10 urological clinics in the US. After provision of informed consent and prior to the scheduled prostate biopsy (≤30 days), up to 20 mL of whole blood will be collected from each subject. The samples will be blinded and sent to Labcorp for evaluation using the Proclarix® assay. Prostate biopsy will be performed according to standard clinical practice of the urologist (systematic, targeted, or combined biopsy with a transrectal or transperineal approach with or without prior magnetic resonance imaging (MRI)). A minimum of 10 cores are required. Histopathological examination of the biopsy specimen will be performed according to the established local practice. A csPCa is defined as ISUP Grade Group ≥2 detected on biopsy. The assay results will be compared to the biopsy results.

Prostate cancer remains a leading cause of cancer-related morbidity and mortality in men worldwide, with significant disparities in incidence and outcomes across different ethnic groups with black men being affected by prostate cancer earlier, more frequently and with more aggressive disease (Tyler B. Kratzer, 2025). Current risk stratification tools often lack the precision needed to effectively assess and predict prostate cancer risk in diverse populations (Daniël F. Osses, 2019). Proclarix® is a blood-based test that addresses the problem of prostate cancer (PCa) overdiagnosis by indicating the risk of clinically significant disease. It is comprised of two novel biomarkers, thrombospondin 1 (THBS1) and cathepsin D (CTSD), and is combined with total prostate-specific antigen (tPSA), free PSA (fPSA) and age. A software algorithm returns a risk score that can be used as an aid in the identification of clinically significant PCa (csPCa), defined as International Society of Urological Pathology (ISUP) Grade Group ≥ 2. Proclarix® has been developed and validated on 955 men, in majority of Caucasian background with 90% sensitivity, 43% specificity, 95% negative predictive value (NPV) and 25% positive predictive value (PPV) (Helmut Klocker, 2020). The validation performance established on German and Austrian patients has been fully confirmed in other European populations: the United Kingdom, Spain, Denmark, Italy and Switzerland. To be used broadly, confirmation of Proclarix® performance in patients from diverse ethnic backgrounds requires further investigation.