Performance Evaluation of a New HRD Assay (HRDsig) in Ovarian Carcinomas in Australia.

Homologous recombination repair (HRR) is the preferred pathway for repairing double-strand DNA breaks, using proteins like BRCA1 and BRCA2, among others, while the PARP-mediated repair pathway is primarily used for single-strand breaks. When a tumour becomes HRR-deficient (HRD), then those tumour cells become reliant on PARP-mediated repair. Poly ADP-ribose polymerase inhibitors, olaparib and niraparib, have been approved in Australia for advanced (FIGO III-IV), high-grade serous or other high-grade ovarian, fallopian tube or primary peritoneal carcinoma with homologous recombination deficiency (HRD). HRDsig (Roche Inc) is a new HRD biomarker that is part of the AVENIO Tumor Tissue CGP Kit V2. We have studied the performance of HRDsig against two NATA (National Association of Testing Authorities, Australia) accredited HRD assays in the cases of high-grade ovarian carcinomas. We have evaluated the performance of HRDsig using a total 40 HRD results against the two accredited HRD assays, as well as against commercial controls and inter-laboratory comparison samples. HRDsig has demonstrated a high concordance rate for HRD by comparing it with two different locally accredited HRD assays in cases of ovarian cancers. These findings provide real-world evidence of the performance of a new HRD assay (HRDsig) in ovarian carcinomas.