285O - Prevalence of homologous recombination deficiency in ovarian, primary peritoneal, and/or fallopian tube cancer: Results from the international HALO study

Background

Homologous recombination deficiency (HRD) prevalence and utilization of different HRD testing kits are not well-characterized across geographies. The HALO study (NCT04991051) determined the prevalence of HRD in patients (pts) with high-grade serous or endometrioid ovarian cancer (HGSOC/HGEOC), primary peritoneal cancer (PPC), and/or fallopian tube cancer (FTC) across Asia, Middle East and Africa (MEA) and Russia.

Methods

This cross-sectional multinational study enrolled consenting adult women with newly diagnosed stage III or IV (FIGO 2014) HGSOC or HGEOC, PPC and/or FTC having formalin-fixed paraffin tumour blocks collected within 120 days of enrolment. We present the prevalence of HRD with genomic instability (GI) excluding tumour BRCA1/2 mutation (tBRCA1/2m) and tBRCA1/2m only using next-generation sequencing (NGS).

Results

Overall, 734 pts (median age, 59.0 [range 23.0, 89.0] yrs) recruited between May-21 and Oct-22 across Asia (n=76), MEA (n=195) and Russia (n=463) were analysed. Majority (88.1%) never smoked, had attained menopause (83.9%) and were multiparous (78.8%). 34.1% had family history of cancer. Most (92.9%) had primary tumour in the ovaries, followed by PPC (4.1%) and FTC (3.0%). HRD status was analysed in 662 pts; of whom 56.0% (371) were HRD positive— 30.8% (204) had GI high score excluding tBRCA1/2m, and 25.2% (167) had tBRCA1/2m. HRD prevalence in Asia, MEA and Russia were 52.0%, 52.2% and 58.5%, respectively. Commercial kits were frequently used for HRD testing (374, 56.5%); predominantly Amoydx (329, 88.0%). Table: 285O

Prevalence of HRD

HRD positivity: deleterious/suspected pathogenic tBRCA1/2m and/or GI positive (per reference laboratory of each country and NGS-based in vitro diagnostic test).

Conclusions

This pioneering real-world study reports HRD prevalence in a large cohort of pts, ranging from 52.0% - 58.5% across the three study regions. Our results highlight the unmet need for capturing biomarker testing data and the utility of different HRD testing kits in real-world in resource-limited settings to inform treatment decisions.

Clinical trial identification

NCT04991051.

Editorial acknowledgement

This study was funded by AstraZeneca. As per the GPP3 guidelines, the authors would like to thank Dr. Soma Santra of Fortrea Scietific Pvt. Ltd, for medical writing support.

Legal entity responsible for the study

AstraZeneca International.

Funding

AstraZeneca International.

Disclosure

A. Tyulyandina: Financial Interests, Personal, Advisory Board, AstraZeneca, Advisory Board, Personal Biocad, Advisory Board, Personal Eisai, Invited Speaker, Personal MSD, Advisory Board, Personal Pfizer, Expert Testimony, Personal Roche, Invited Speaker, Personal Non-Financial Interests AstraZeneca, Principal Investigator Biocad, Principal Investigator MSD, Advisory Role MSD, Principal Investigator Roche, Principal Investigator: AstraZeneca. All other authors have declared no conflicts of interest.