Harmonization of Homologous Recombination Deficiency testing in Ovarian Cancer: results from the MITO16A/MaNGO-OV2 trial

Background Homologous Recombination Deficiency (HRD) status predicts response to treatment with poly(ADP-ribose) polymerase inhibitors in Ovarian Cancer (OC) patients. The Myriad myChoiceCDx Assay is approved by Food and Drug Agency for the HRD assessment.Here we compared the HRD status obtained by three commercial panels with the results from Myriad reference test. Methods The HRD analysis was performed on DNA from formalin-fixed and paraffin-embedded tumor samples of 100 untreated OC patients for which Myriad assay results were available, using TruSight Oncology 500 HRD assay (Illumina), Oncomine Comprehensive Assay Plus (Thermo Fisher Scientific) and SOPHiA DDM HRD solution panel (SOPHiA Genetics). Results A good overall concordance with the reference method was demonstrated at three different levels: BRCA mutational status (from 94.4% to 97.7%), the genomic instability value (from 88.2% to 95.3%) and for the HRD status (from 90.4% to 97.6%). Moreover, a trend in favour of HRD positive patients for response rate, progression-free survival and overall survival similar to Myriad was observed for all three tests. Discussion Our data suggest the feasibility of commercial testing for assessing HRD status, with a good concordance with the reference method and association with clinical outcome.