Paris (France), Mai 19, 2020 – 5.45 pm CEST - Onxeo S.A. (Euronext Paris, NASDAQ Copenhagen: ONXEO), (“Onxeo” or “the Company”), a clinical-stage biotechnology company specializing in the development of innovative drugs targeting tumor DNA Damage response (DDR), in particular against rare or resistant cancers, today announced the presentation of preclinical data supporting the differentiated ability of AsiDNA™, its first-in-class DNA Damage Response (DDR) inhibitor, to reverse resistance to PARP inhibitors (PARPi) by preventing death-tolerant cells (DTC) regrowth. These promising results will be presented in an e-posters session during the American Association for Cancer Research (AACR) annual meeting which, given the COVID-19 context, will be held virtually on June 22-24, 2020.

Françoise Bono, PhD, Chief Scientific Officer of Onxeo, commented: “We continue to strengthen our understanding of AsiDNA™'s unique mechanism of action and have generated new data demonstrating its ability to specifically target drug-tolerant or persistent tumor cells that result in resistance to targeted therapies, and in particular, as we are demonstrating for the first time in this study, resistance to PARP inhibitors. We are delighted to be able to present at this prestigious oncology-focused meeting this new study on the effect of AsiDNA™ on these persistent cells when combined with PARP inhibitors. These results add to AsiDNA™'s strong preclinical file, reinforce the legitimacy of its current development in the clinical setting and confirm its interest and value in our Company's portfolio.”

These new data show for the first time that PARPi resistance can be caused by drug-tolerant cells, and that the addition of AsiDNA™ to PARP inhibitors prevents the regrowth of these cells, thereby completely and irreversibly abolishing the emergence of resistance in ovarian tumor cells.

The results from this study are extremely encouraging for the upcoming Phase 1b/2 REVocan study, combining AsiDNA™ with niraparib in the clinical setting in recurrent ovarian cancer, which is expected to start in the second half of 2020. These data clearly reinforce AsiDNA™'s interest in the fight against resistance, which is the main challenge in cancer treatment today.

Session:              PO.ET03.04 - Mechanisms of sensitivity and resistance to DNA damage repair targeting

Date/ Time:       June 22, 2020 - 9:00 AM - 6:00 PM (U.S. Eastern Daylight Time -EDT)

E-poster:             4078 / 8

Click on this link to read the abstract: Acquired resistance to PARP inhibitors evolves from drug-tolerant persister cells vulnerable to AsiDNA™.

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