The REVocan study aims to evaluate the abrogation by AsiDNA™ of tumor resistance to a PARP inhibitor in relapsed ovarian cancer

The first treatments could begin in the next few weeks, with the objective of first results late 2020/early 2021

Paris (France), May 29, 2020 – 7.30 am 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 that the REVocan[1] phase 1b/2 designed to evaluate the effect of AsiDNA™, Onxeo’s first-in-class DDR inhibitor, on the acquired resistance to PARP inhibitor (PARPi) niraparib for 2^nd line maintenance treatment of relapsed ovarian cancer, has received approval from the French National Agency for the Safety of Medicines and Health Products (ANSM) and the Ethics Committee (CPP).

From a regulatory standpoint, the study can now be initiated. REVocan will first start at three internationally renowned French centers, which are recognized experts in medical oncology:

• Gustave Roussy (Paris), the study sponsor under a clinical research agreement signed with Onxeo in early 2020;
• the Western Cancer Institute (Institut de Cancérologie de l’Ouest – Nantes/St Herblain);
• The University Hospital Center of Lyon (Hospices Civils de Lyon – CHU Lyon Sud).

The first patients could be recruited as early as the third quarter of 2020, with the aim of obtaining preliminary results at the end of 2020 or early in 2021.

"I would like to warmly thank the teams at Onxeo and Gustave Roussy who, despite the confinement and difficulties of the current health situation, have worked tirelessly to provide patients suffering from recurrent ovarian cancer with the fastest possible access to AsiDNA™ in this clinical study, which is critical for Onxeo as well as for the medical community," said Olivier de Beaumont, Chief medical Officer of Onxeo. "Given AsiDNA™'s unique mechanism of action, this novel proof-of-concept study of the reversion mechanism of resistance to a PARP inhibitor could pave the way for further combination trials with other targeted therapies in other major diseases and offer patients who benefit from these treatments an increased opportunity to control their disease."

Niraparib has significantly delayed ovarian cancer progression in patients with and without BRCA mutation^[2], but treatment efficacy declines over time as tumors establish new repair pathways and resist treatment. In preclinical studies that replicated the conditions of the REVocan study[3], AsiDNA™ demonstrated its ability to halt the acquired resistance of tumors to PARP inhibitors (class effect). REVocan is therefore particularly important as it would provide proof-of-concept of the tolerability of such a combination and AsiDNA™'s ability to reverse resistance to this major therapeutic class.

[1] REVocan = REV (REVersion of resistance) – OC (in Ovarian Cancer) – A (with AsiDNA™) – N (and Niraparib)

[2] Mansoor R. Mirza, M.D et. al. Niraparib Maintenance Therapy in Platinum-Sensitive, Recurrent Ovarian Cancer N Engl J Med 2016; 375:2154-2164.

[3] Acquired resistance to PARP inhibitors evolves from drug-tolerant persister cells vulnerable to AsiDNA™ - Abstract accepted at the  AACR 2020 Virtual Meeting, to be presented on June 22, 2020.

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