Clinical Performance of Tissue- and Plasma-Based Diagnostic Assays in Identifying Homologous Recombination Repair Gene Alterations in Patients with Metastatic Castration-Resistant Prostate Cancer following Treatment with Niraparib with Abiraterone Acetate Plus Prednisone

This retrospective study was designed to demonstrate the clinical utility of two diagnostic tests, the FoundationOneCDx (F1CDx) and Exact Sciences Resolution homologous recombination deficiency (HRD; Resolution HRD assay) as clinical trial–enrollment assays to identify patients with metastatic castration-resistant prostate cancer harboring homologous recombination repair (HRR) gene alterations. Tumor tissue and plasma collected from patients with metastatic castration-resistant prostate cancer in the phase 3 MAGNITUDE study were tested using the F1CDx tissue assay and/or the Resolution HRD plasma assay.