Regulatory News:

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, announces that today’s Shareholders’ General Meeting approved all the ordinary resolutions, with over 87% of favourable votes.

The company's shareholders notably renewed the terms of office of Judith Greciet, Financière de la Montagne and Christine Garnier as directors for a further period of three years.

Onxeo would like to thank all of its shareholders for their commitment and support.

Given the constraints of the COVID-19 context, Onxeo's Annual General Meeting was held in camera and was webcast live on the Internet.

The quorum of 21.01% did not permit the resolutions to be discussed on an extraordinary basis and an Extraordinary General Meeting on the second call will be held on June 19, 2020 at 10 am (CEST), also in camera. The shareholders of the Company who have not cast their vote so far are thus invited to vote exclusively through mail or online voting prior to the General Meeting on the second call:

- online voting is available and must be used as a priority: the secure voting platforms VOTACCESS in France and Computershare in Denmark are reopened as of today;

- alternatively, shareholders can also vote by postal ballot, in accordance with the terms and conditions indicated in the prior notice published in the BALO on April 24, 2020.

The vote of shareholders who submitted their vote remotely at the first general meeting remains valid and counted for the general meeting on the second call

All documents relating to this General Meeting remain available on the company's website, in the General Meetings section. If you have any questions about voting procedures, please contact the Investor Relations team by e-mail at ag2020@onxeo.com.

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About Onxeo

Onxeo (Euronext Paris, NASDAQ Copenhagen: ONXEO) is a clinical-stage biotechnology company developing innovative oncology drugs targeting tumor DNA-binding functions through unique mechanisms of action in the sought-after field of DNA Damage Response (DDR). The Company is focused on bringing early-stage first-in-class or disruptive compounds from translational research to clinical proof-of-concept, a value-creating inflection point appealing to potential partners.

platON™ is Onxeo’s proprietary chemistry platform of oligonucleotides acting as decoy agonists, which generates new innovative compounds and broaden the Company’s product pipeline.

AsiDNA™, the first compound from platON™, is a first-in-class, highly differentiated DNA Damage Response (DDR) inhibitor based on a decoy and agonist mechanism acting upstream of multiple DDR pathways. Translational research has highlighted the distinctive properties of AsiDNA™, notably its ability to abrogate tumor resistance to PARP inhibitors regardless of the genetic mutation status. AsiDNA™ has also shown a strong synergy with other tumor DNA-damaging agents such as chemotherapy and PARP inhibitors. The DRIIV-1 (DNA Repair Inhibitor-administered IntraVenously) phase I study has evaluated AsiDNA™ by systemic administration (IV) in advanced solid tumors and confirmed the active doses as well as a favorable human safety profile. The ongoing DRIIV-1b extension study is assessing the safety and efficacy of a 600 mg dose of AsiDNA™ in combination with carboplatin and then with carboplatin and paclitaxel, in patients with solid tumors who are eligible for such treatments.

OX401 is a new drug candidate from platON™, optimized to be a next-generation PARP inhibitor acting on both the DNA Damage Response and the activation of immune response, without inducing resistance. OX401 is undergoing preclinical proof-of-concept studies, alone and in combination with immunotherapies.

For further information, please visit www.onxeo.com.

Forward looking statements

This communication expressly or implicitly contains certain forward-looking statements concerning Onxeo and its business. Such statements involve certain known and unknown risks, uncertainties and other factors, which could cause the actual results, financial condition, performance or achievements of Onxeo to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Onxeo is providing this communication as of this date and does not undertake to update any forward-looking statements contained herein as a result of new information, future events or otherwise. For a discussion of risks and uncertainties which could cause actual results, financial condition, performance or achievements of Onxeo to differ from those contained in the forward-looking statements, please refer to chapter 3 “Risk Factors” ("Facteurs de Risque") of the Company’s universal registration document filed with the Autorité des marchés financiers on April 27, 2020 under number D.20-0362, which is available on the websites of the Autorité des marchés financiers (www.amf-france.org) an the Company (www.onxeo.com).