Abstract 6013: VIO-01, a pan-DDR DNA decoy mediating DNA repair abrogation and unleashing the anti-tumor immune response

Abstract Background: Targeting specific DNA Damage Response (DDR) proteins has been worldwide studied and developed, with the example of PARP inhibitors being the only approved treatments in this field. Here, we describe the antineoplastic and immunomodulatory effects of VIO-01, a first-in-class DNA decoy-cholesterol conjugate, that operates as a pan repair proteins decoy, resulting in constitutive exhaustion of the DNA damage response. Methods: VIO-01-induced DDR proteins trapping and cell cytotoxicity were examined in both homologous recombination proficient (HRP) and deficient (HRD) cancer cells. DNA repair efficacy was monitored by analyzing repair protein recruitment to damage sites. RNAseq analysis in HRP/HRD ovarian cancer cells was employed to uncover the molecular mechanisms underlying VIO-01 effects. Effects on the innate and adaptive immune responses were assessed by following T-cell mediated anti-tumor cytotoxicity. VIO-01 antitumor efficacy and biodistribution were also assessed. Additionally, the interest of cholesterol as a vector for VIO-01 was analyzed compared to other ligands like the folate receptor ligand. Results: VIO-01 bounds to several DDR proteins, such as PARP1, KU70/80, MRN complex and MSH2/MSH3 with high affinity, resulting in an abrogation of single- and double-strand break repair. In line with this, and through global transcriptome analysis, VIO-01 treatment resulted in notable downregulation of Base Excision Repair, NHEJ and Nucleotide Excision Repair pathways in both HRP/HRD cell lines. Additionally, VIO-01 elicited the activation of the immune system and inflammatory responses in ovarian cancer cells. Conjointly, VIO-01 treatment induced a significant differentiation of monocytes into non-classical monocytes, leading to a shaping of the tumor microenvironment via CD8+ T cell recruitment in early stage of activation. The activity of VIO-01 was specific to tumor cells, while sparing healthy and immune cells, at odds with PARP inhibitors. In line with in vitro results, VIO-01 mediated antitumor efficacy in vivo coupled to tumor-targeting T-cell responses. These interesting effects were driven by a favorable ADME/PK profile, showing a long-lasting VIO-01 residence time VIO-01 into tumors (at least 3 days post treatment), coupled to a clear hijacking from the liver and a rapid blood clearance, ensuring a minimal toxicity. Moreover, regulatory toxicology studies demonstrated a favorable safety profile of VIO-01 in non-human primate with the major findings being a transient increase in complement factors induced by the binding of VIO-01 to factor H, which was not observed in human serum, predicting favorable safety profile in humans. Conclusions: Our results provide a preclinical rationale for using VIO-01 to trigger DNA damage exhaustion and an antitumor immune response, paving the way for rapid clinical application in patients bearing HRD or HRP tumors. Citation Format: Vlada Zakharova, Chloe Doizelet, Nicolas Babault, Marie-Christine Lienafa, Fetta Mazed, Megane Debiais, Pierre Vilela, Emilie Perroud, Wael Jdey. VIO-01, a pan-DDR DNA decoy mediating DNA repair abrogation and unleashing the anti-tumor immune response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6013.