Abstract PO2-19-11: NOBLE – Neoadjuvant Olaparib and Durvalumab for patients with BRCA-associated TripLE Negative Breast Cancer

Abstract Background The standard of care for patients with early triple-negative breast cancer (TNBC) is neoadjuvant chemotherapy followed by surgery. Recently, immune checkpoints inhibitors (ICI) added to neoadjuvant chemotherapy have shown efficacy. Among TNBC, BRCA mutations and other homologous recombination deficiency (HRD) signals are relatively frequent. As opposed to other types of breast cancer, TNBC show a high neoantigen load, a large number of tumour infiltrating lymphocytes (TILs), and a high PD-L1 expression. In BRCA/HRD breast cancer, PARP inhibitors (PARPi) exhibit a distinct anticancer activity. In addition, they show immunomodulatory effects by promoting PD-L1 expression and DNA damage, increasing neoantigen load. Chemotherapy-free regimens combining PARPi and ICI result in promising synergistic activity as shown in the metastatic setting, supporting investigation in the neoadjuvant setting. Trial design NOBLE is an EORTC phase 2, randomized, international, multicentre, open label, clinical trial. Eligible patients will undergo central screening for tumoral BRCA/HRD (Institute Curie, 455 patients), 152 patients will be randomized 1:1 between olaparib vs olaparib and durvalumab for 4 cycles (16 weeks) of neoadjuvant treatment. Thereafter, patients will undergo surgery. All patients will be followed-up to 2 years (y) after surgery. The trial will be conducted in 3 steps (screening/randomization): Step 1 – Feasibility (60/20): to assess the central testing failure rate, the turn-around time for central testing and the prevalence of tBRCA/HRD; Step 2 (193/64) – Futility; and Step 3 (202/152) – Expansion of recruitment. The primary endpoint is the rate of pathologic complete response (pCR) at the time of surgery, defined as ypT0/is ypN0. Secondary endpoints are response based on RECIST v1.1, surgery rate, 2-y event-free-survival, 2-y overall survival, safety, and quality of life. The study is expected to be activated in early autumn 2023 and the primary endpoint will be available approximately 5 years after the screening of the first patient. Main inclusion criteria Histologically confirmed primary TNBC, defined as: - ER and PgR ≤ 10% - HER2-negative per ASCO CAP guidelines Stage T1c-T2 N0-N1 M0 BRCA mutation and/or HRD based on methylation as determined by central testing ECOG status 0-1 Written informed consent Age ≥18 years No prior systemic therapy nor surgery for the current Main exclusion criteria Previous treatment with a PARPi or an immune-checkpoint inhibitor History of previous invasive breast cancer Bilateral and/or multifocal and/or multicentric BC Autoimmune or inflammatory disease Specific aims The aim of this study is to provide a safe and effective neoadjuvant treatment free of chemotherapy to a distinct subpopulation among patients with TNBC. We will evaluate the pCR after neoadjuvant treatment with olaparib alone and with olaparib in combination with durvalumab in patients with TNBC showing a BRCA1/2 mutation or HRD based on methylation. Statistical methods The sample size was calculated based on the minimax Simon two-stage design including an interim analysis for futility of the primary endpoint. Decision rules are pre-specified in the study protocol. Each treatment arm will be analyzed independently. There will be no formal comparison between the two experimental treatment arms. A minimization technique will be used for random treatment allocation stratifying for the type of HRD alteration, PD-L1 expression level and for TILs. Accrual We expect to start recruiting in September 2023. We aim to screen 455 patients to randomize 152 patients. Contact information for people with a specific interest in the trial Etienne Brain (study coordinator): etienne.brain@curie.fr Anne-Sophie Hamy-Petit (study co-coordinator): anne-sophie.hamy-petit@curie.fr Citation Format: Emanuel Buhrer, Eleni Xenophontos, Anne-Sophie Hamy-Petit, Jose Casas-Martin, Céline Callens, Thomas Meyskens, Coralie Poncet, Anastasia Lanzi, Etienne Brain. NOBLE – Neoadjuvant Olaparib and Durvalumab for patients with BRCA-associated TripLE Negative Breast Cancer abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-19-11.