Introduction/Background Maintenance treatment after chemotherapy/surgery has become a standard of care in patients with advanced epithelial ovarian cancer (EOC). Several targeted drugs have been approved, allowing for multiple therapeutic options, including bevacizumab and/or PARP inhibitors (PARPi). A Delphi study was conducted with European experts to understand the heterogeneity of clinical practice and identify key drivers for decision-making regarding maintenance treatment among different options.

Methodology A pragmatic literature review identified questions with uncertain answers regarding optimal assays and maintenance treatment strategies in patients with EOC. A panel of 16 experts were asked to answer ‘yes’ or ‘no’ to 25 questions (comprising a total 117 sub-items). For each question, a consensus was reached when ≥80% of participants agreed. After each round, questions with no consensus were reformulated; final round results were analysed.

Results Panellists consensually agreed that both BRCA mutation and homologous recombination deficiency (HRD) status should be assessed in parallel with initial histopathological diagnosis, and that first-line (1L) platinum chemotherapy could be started concurrently. There was consensus that other academic HRD tests are acceptable, provided they are validated prior to testing. Panellists agreed that high-risk disease was a FIGO stage III tumour operated with incomplete resection, regardless of size of residual disease and surgery timing, or a FIGO stage IV tumour, meaning that complete interval debulking surgery could potentially be considered at low risk for disease recurrence. The decision for maintenance treatment with a PARPi, bevacizumab, or both, was based on clinician consideration of the high risk or low risk, and response to 1L platinum chemotherapy, including RECIST criteria and KELIM.

Conclusion Among multiple therapeutic options, the key drivers for selecting maintenance treatments for EOC in routine practice included: clinician perception regarding the risk for early disease progression (based on criteria slightly different from published clinical trials), chemosensitivity and molecular characteristics (BRCA/HRD status).

Disclosures Benoit You has nothing to disclose. Alejandro Fidalgo had Advisory roles for AstraZeneca, GSK-Tesaro, Clovis, Pharmamar, Abilify pharma, Eisai; was a speaker for AstraZeneca, GSK-Tesaro, Clovis, Pharmamar; has received research grants from GSK, Pharmamar, AstraZeneca and Novartis.Barbara Schmalfeldt received grants/research support from AstraZeneca, Roche, MSD, GSK; has honoraria or consultation fees from AstraZeneca, Roche, MSD, GSK, Eisai; Company sponsored seaker’s bureau: AstraZeneca, Roche, MSD, GSK, Eisai. Angela George has honoraria fees from Astra Zeneca, GSK, Merck, Roche, Clovis; was a speaker for: AstraZeneca, GSK, Merck, Clovis. Charlie Gourley has received grants from: AstraZeneca, MSD, Novartis. GSK, BerGen Bio, Merdannex, Roche, Verastem; has honoraria fees from AstraZeneca, MSD, GSK, Clovis, Verastrem, Takeda, Eisai, Cor2Ed, Peer Voice. Sandro Pignata has honoraria fees from Astrazeneca, MSD, GSK, Roche and clovis; has received research funding from Astrazeneca, MSD, GSK, and Roche. Domenica Lorusso had Consulting/Advisory Roles at: Eisai, AstraZeneca, GlaxoSmithKline, MSD/Merck, ImmunoGen, Clovis, Genmab, Seagen; has received research funding from: Clovis (Inst), GSK (Inst), MSD (Inst). Pilar Barretina has nothing to disclose. Ignacio Romero has received grants/research from Roche, Astra Zeneca, GSK; has honoraria fees from: Pharmamar, Roche, AZ, GSK, MSD; was a sponsored speaker for: Pharmamar, Roche, AstraZeneca, GSK, MSD. Christoph Grimm has received grants/research support from: AstraZeneca, Meda Pharma, Roche Diagnostics; has honoraria or consultation fees from: AstraZeneca, Celgene, Clovis, Eisai, GSK, MSD, PharmaMar, Roche, Vifor Pharma; company sponsored speakers bureau: Amgen, AstraZeneca, Eisai, GSK, MSD, PharmaMar, Roche. Toon Van Gorp received funding for grants/research from: Amgen, AstraZeneca, Roche; has honoraria fees: AstraZeneca, Eisai, GSK, ImmunoGen, MSD, OncXerna, Seagen, Tubulis; Company sponsored speaker for GSK. Maria Rossing has received Grants/Research from: Neye Foundation, Novo Nordisk Foundation, AstraZeneca; Honoraria or consultation fees: Laegeforeningen/Danish Medical Association, AstraZeneca and GSK. Dearbhaile Collins has honoraria fees from: Amgen, AZD, GSK, Janssen, Pfizer, MSD Oncology; Consulting or Advisory Role: SeaGen, Genmab, MSD Oncology, GSK; received Research Funding: Roche, Pfizer. Josefin Fernebro has honoraria fees from: AstraZeneca, GSK. Line Bjørge received Grants/research supports from: AstraZeneca. Alexandra Leary funding from Sanofi, Roche, GSK, BMS, AZ, Ose Immuno, Lovance, Agenus, Arcagy Gineco; Honoria: Ability Pharma, Apmonia, AZ, blueprint, GSK, MSD, Clovis, Merck Serono, Onko+, Zentalis, Kephren, Medscape. Thibault de la Motte Rouge recieved Grants/research supports: Seagen, MSD, Pfizer; Honoraria or consultation fees: AstraZeneca, Pfizer, MSD, GSK, Gilead, Clovis Oncology, ESAI; Company sponsored speakers bureau: AstraZeneca, GSK, MSD. Phillip Harter received grants: AZ, Roche, GSK, Genmab, Immunogen, Seagen, Clovis, Novartis; honoraria: Amigen, AZ, Clovis, Eisal, Excelentia, GSK, Immunogen, Mersena, Mitenyl, MSD, Roche, Sotio, Stryker. Christian Kurzeder received honoraria or consultation fees: GSK, AstraZeneca, Novartis, Pharmamar, Genomic Health, Roche, Eli Lilly, Merck MSD, Pfizer, Daiichy Sankyo; Company sponsored speaker’s bureau: GSK, AstraZeneca, Novartis and Roche; Travel support: GSK, AstraZeneca, Roche. Joana Bordalo e Sá yes received honoraria or consultation fees: AstraZeneca, GSK and MSD; Grants/research supports: AstraZeneca, Novartis, Pfizer and Roche.