Celyad Oncology SA — Major Shareholding Notification 2014

Aug 7, 2014

Press release Regulated information August 7, 2014 – 17:45 CET

Information on the total number of voting rights and shares

(Article 15 of the Law of 2 May 2007)

Cardio3 BioSciences SA (NYSE Euronext Brussels and NYSE Euronext Paris: CARD), discloses the information required under article 15, § 1 of the Law of 2 May 2007 regarding the disclosure of important shareholdings in listed companies.

Figures – modified on 4 August 2014 following the exercise of warrants New shares issued following the exercise of Company's warrants: 5.750 Company's share capital: 24,597,080.63 Euros Total number of shares with voting rights: 7,035,387 Total number of voting rights (= denominator): 7,035,387

Statutory thresholds – unchanged

Statutory thresholds for participation (article 12 of the by-laws): 5%, 10%, 15%, 20% and so on by increments of 5%.

Contact person for regulated information (financials, transparency etc.): Patrick Jeanmart, Chief Financial Officer (CFO): pjeanmart@c3bs.com

Further questions about the content of this release can be sent to investors@c3bs.com.

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For further information, please contact:

Cardio3 BioSciences Patrick Jeanmart, CFO www.c3bs.com pjeanmart@c3bs.com

About Cardio3 BioSciences

Cardio3 BioSciences is a Belgian leading biotechnology company focused on the discovery and development of regenerative and protective therapies for the treatment of cardiac diseases. The company was founded in 2007 and is based in the Walloon region of Belgium. Cardio3 BioSciences leverages research collaborations in the US and in Europe with Mayo Clinic and the Cardiovascular Centre Aalst, Belgium. The Company's lead product candidate C-Cure® is an innovative pharmaceutical product that is being developed for heart failure indication. C-Cure® consists of a patient's own cells that are harvested from the patient's bone marrow and engineered to become new heart muscle. This process is known as Cardiopoiesis. Cardio3 BioSciences has also developed C-Cath®ez, the most technologically advanced injection catheter with superior efficiency of delivery of bio therapeutic agents into the myocardium. Cardio3 BioSciences' shares are listed on Euronext Brussels and Euronext Paris under the ticker symbol CARD.

Information

In accordance with the Bayh-Dole Act, Mayo Clinic has licensed the technology underlying C-Cure® to Cardio3 BioSciences and received an equity position in the company in the context of the license. Mayo Clinic and the inventors of the technology, Drs. Andre Terzic and Atta Behfar, have a financial interest associated with the technology related to this research. While no royalties have accrued to date, Mayo Clinic has rights to receive future royalties which will be shared with Drs. Terzic and Behfar in accordance with the Mayo Clinic Royalty sharing policy.

C3BS-CQR-1, C-Cure, C-Cath, Cardio3 BioSciences and the Cardio3 BioSciences and C-Cath logos are trademarks or registered trademarks of Cardio3 BioSciences SA, in Belgium, other countries, or both. Mayo Clinic holds equity in Cardio3 BioSciences as a result of intellectual property licensed to the company. In addition to historical facts or statements of current condition, this press release contains forward-looking statements, which reflect our current expectations and projections about future events, and involve certain known and unknown risks, uncertainties and assumptions that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements. These risks, uncertainties and assumptions could adversely affect the outcome and financial effects of the plans and events described herein. These forward-looking statements are further qualified by important factors, which could cause actual results to differ materially from those in the forward-looking statements, including timely submission and approval of anticipated regulatory filings; the successful initiation and completion of required Phase III studies; additional clinical results validating the use of adult autologous stem cells to treat heart failure; satisfaction of regulatory and other requirements; and actions of regulatory bodies and other governmental authorities.