Introduction/Background The value of homologous recombination deficiency (HRD) testing in patients with advanced ovarian cancer (AOC) is increasingly being recognized to guide poly(ADP-ribose) polymerase inhibitor maintenance treatment following first-line chemotherapy. This study characterizes the current HRD testing landscape, building upon previous presentations to also evaluate timing of HRD tests relative to BRCA mutation (BRCAm) testing.

Methodology The first of three survey waves was conducted from July–November 2022. US and European (UK, France, Germany, Austria) physicians/molecular pathologists were recruited from clinical sites/laboratories conducting HRD testing and via a standing physician panel.

Results 287 participants responded (representing invitees from ~9% sites, <2% panellists); 265 completed the survey. US and European physicians estimated that most (70%) newly diagnosed AOC patients underwent HRD testing. Almost all (97%) physicians conducted HRD tests to inform treatment decisions (table 1). The timing of HRD testing and most frequently used HRD test types are reported in the table 1. Most (70%) US and European participants conducted HRD testing in parallel with BRCAm testing, most commonly reporting that this was because tests were combined in the same panel (66%; table 1). Test costs were often partially (US: n=125; 53%; Europe: n=47; 27%) or fully covered (US: n=48; 21%; Europe: n=89; 51%). Results were received within (mean ± SD) 10 ± 6 and 16 ± 11 working days in the US and Europe, respectively. Most US (n=71, 80%) and European (n=108, 78%) institutions offered genetic counselling.

Conclusion Physicians conducting HRD testing reported that most of their newly diagnosed AOC patients underwent HRD testing, primarily to inform treatment decisions. Both physicians and molecular pathologists most commonly conducted HRD testing in parallel with BRCAm testing. Differences between the US and Europe included test types, test cost coverage, and time to receive results, indicating potential areas for improvement in HRD testing to further benefit patients.

Disclosures AL: Served in consultant/advisory roles for AstraZeneca, Blueprint Medicines, Clovis Oncology, GlaxoSmithKline, Merck Serono, MSD, PEGASCY, Tesaro, and Zentalis; received research grants or support from Inivata and Sanofi; received travel/accommodation expenses from AstraZeneca; been on the speakers’ bureau for or received honoraria from Medscape

MH: Employee and stockholder at AstraZeneca

TF: Employee and stockholder at AstraZeneca

CI: Employee and stockholder at AstraZeneca

EJ: Employee and stockholder at AstraZeneca

BS: Employee at ICON Commercial Solutions

DRC Employee at ICON Commercial Solutions

RLC Served in consultant/advisory roles for Abbvie, Agenus, Alkermes, AstraZeneca, Clovis, Deciphera, Genelux, Genmab, GSK, Immunogen, Merck, Novocure, OncoQuest, Onxerna, Regeneron, and Roche/Genentech; received research grants or support from AstraZeneca, Clovis, Genelux, Genmab, Immunogen, Merck, and Roche/Genentech; is an employee of US Oncology; been on the speakers’ bureau for or received honoraria from AstraZeneca, Clovis, Merck, and Roche/Genetech; and has participated on a Data Safety Monitoring Board or Advisory Board for VBL Therapeutics and Eisai/BMS