Onxeo

Share Issue/Capital Change • Aug 31, 2015

Capital increase in Onxeo resulting from the exercise of share subscription options from employees

Paris (France), Copenhagen (Denmark), August 31, 2015 – Onxeo S.A. (Euronext Paris, NASDAQ Copenhagen: ONXEO), an innovative biopharmaceutical company specialized in the development of orphan oncology drugs, has increased its share capital by a nominal amount of €4,357.50 following the issue of 830 shares each with a nominal value of €0.25 and resulting from the exercise of share subscription options from employees of the company.

The new shares were fully paid up in cash. As a result, the total number of shares comprising the capital has increased from 40,544,204 to 40,552,083 and Onxeo's share capital amounts to €10,138,020.75

About Onxeo

Onxeo has the vision to become a global leader and pioneer in oncology, with a focus on orphan or rare cancers, through developing innovative therapeutic alternatives designed to "make the difference". The Onxeo team is determined to develop innovative medicines that provide patients with hope and significantly improve their lives.

Key orphan oncology products at the advanced development stage are:

Livatag® (doxorubicin Transdrug™): Phase III in hepatocellular carcinoma Validive® (clonidine Lauriad® ): Phase II in severe oral mucositis: Positive final results Beleodaq® (belinostat): registered in the US in 2nd line treatmentof peripheral T-cell lymphoma For more information, visit the website www.onxeo.com

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Disclaimer

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 the Risk Factors ("Facteurs de Risque") section of the 2014 Reference Document filed with the AMF on April 14, 2015, which is available on the AMF website (http://www.amf-france.org) or on the company's website (www.onxeo.com).

Contacts :

Judith Greciet, CEO j.greciet@onxeo.com Nicolas Fellmann, CFO n.fellmann@onxeo.com +33 1 45 58 76 00

Caroline Carmagnol and Florence Portejoie onxeo@alizerp.com +33 6 64 18 99 59 / +33 6 47 38 90 04