Celyad Oncology : Summary Note – EN

SUMMARY NOTE

This summary note (the "Summary Note") has been prepared by Celyad Oncology SA (the "Company" or "Celyad") in relation to the admission to trading of up to 2,595,777 new shares on Euronext Brussels and Euronext Paris (the "New Shares"). This Summary Note has been approved by the Belgian Financial Services and Markets Authority (Autorité des services et marches financiers, the "FSMA") on [8 June] 2021, and subsequently notified to the French Financial Markets Authority (Autorité des Marchés Financiers, the "AMF"), and should be read in conjunction with the following documents:

• the Company's registration document as approved by the FSMA on 1st June 2021 (the
  "Registration Document"); and
• the Company's securities note in relation to the admission to trading of up to 2,595,777 New Shares on Euronext Brussels and Euronext Paris as approved by the FSMA on 8 June 2021 and as subsequently notified to the AMF (the "Securities Note").

The Registration Document and the Securities Note, together with this Summary Note, constitute a prospectus within the meaning of article 10 of the Prospectus Regulation 2017/1129 (the "Prospectus Regulation").

The Board of Directors of Celyad assumes responsibility for the content of the Prospectus. The Board of Directors declares that, to the best of its knowledge, the information contained in the Summary Note makes no omission likely to affect its import.

On behalf of the Board of Directors,

______________________________

Filippo Petti Managing Director

Summary of the Prospectus

This Summary Note is to be read together with the Registration Document and the Securities Note, which together constitute a prospectus (the "Prospectus") within the meaning of article 10 of the Prospectus Regulation.

This Summary Note is prepared in accordance with article 7 of the Prospectus Regulation. In accordance with this provision, the Summary Note is divided into four main sections numbered from A to D.

1. Introductions and warnings

Element	Disclosure requirement

A.1 Introduction

Name and International Securities Identification Number

2,777,777 new shares were issued, under the condition of their subscription by investors, by the Company's board of directors on 3 September 2020. Out of the 2,777,777 new shares, 182,000 new shares have been subscribed and issued on May 2021 and 2,595,777 new shares are still outstanding (the "New Shares"). The New Shares are all ordinary shares and rank pari passu in all respects with the other existing and outstanding shares of the Company (the "Shares"). The New Shares will be offered to subscription by Celyad in the U.S. through at-the-market ("ATM") offerings. The New Shares will be subscribed from time to time and over a limited period of time until 2 September 2023, at the market price of the Share.

The international securities identification number (ISIN) of the New Shares is BE0974260896-

XBRU

Identity and contact details of the Company

Celyad Oncology SA, a public limited liability company organized under the laws of Belgium with registered office located at rue Edouard Belin 2, 1435 Mont-Saint-Guibert, registered with the Belgian legal entities (Nivelles) under enterprise number 0891.118.115 and with 549300ORR0M8XF56OI64 as Legal Entity Identifier (LEI), the Company's telephone number is [phone]

Competent authority

Belgian Financial Services and Markets Authority (FSMA), Congresstraat 12-14, 1000 Brussels, its telephone number is [phone]

Date of approval of the Prospectus

The Registration Document has been approved by the FSMA on 1st June 2021. The Securities Note and the Summary Note have been approved by the FSMA on 8 June 2021.

A.2 warnings

This Summary Note must be read as an introduction to the Prospectus and includes certain important information included in the Prospectus, but does not include all the information that may be important or relevant to the investors. This Summary Note must be read in conjunction with the more detailed information included in the Prospectus (including the information incorporated by reference). It should also be read together with the matters included in the section "Risk Factors" of the Prospectus. Any decision to invest in the securities of Celyad should be based on the investor's consideration of the Prospectus as a whole. While acquiring securities issued by Celyad, investors must be aware that they could lose all or part of the invested capital.

No civil liability will attach to the persons responsible for this Summary Note, including any translation thereof, unless it is misleading, inaccurate or inconsistent when read together with the other parts of this Prospectus, or it does not provide, when read together with the other parts of this Prospectus, key information in order to help investors when considering whether to invest in the Shares. Where a claim relating to this Prospectus is brought before a court in a Member State of the European Economic Area, the plaintiff may, under the national legislation of the Member State

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where the claim is brought, be required to bear the costs translating this Prospectus before the legal proceedings are initiated.

1. Key information on the Company

Element	Disclosure requirement
B.1	Who is the issuer of the securities ?
	Identification - The issuer is a public limited liability company organized under the laws of
	Belgium with registered office located at rue Edouard Belin 2, 1435 Mont-Saint-Guibert, registered
	with the Belgian legal entities (Nivelles) under enterprise number 0891.118.115 and with
	549300ORR0M8XF56OI64 as Legal Entity Identifier (LEI).
	Principal activities - Celyad is a clinical-stage biotechnology company focused on the discovery
	and development of chimeric antigen receptor T (CAR T) cell	therapies for cancer. The Company
	is developing a pipeline of allogeneic and autologous CAR T cell therapy candidates for the
	treatment of both hematological malignancies and solid tumors.
	Its clinical drug product candidates include the autologous cell therapies CYAD-02 for the treatment
	of relapsed / refractory acute myeloid leukemia (r/r AML), the allogeneic, or off-the-shelf, cell
	therapy CYAD-101 for the treatment of metastatic colorectal cancer (mCRC) and the one of CYAD-
	211 for the treatment of patients with multiple myeloma, as well as other candidates from CYAD-
	200 series generated from the shRNA non-gene-edited platform.
	Major shareholders - At the date of this Summary Note, the following parties are the shareholders
	of the Company that hold 5% or more of the total number of Shares (i.e. 15,187,156 Shares):
	TOLEFI SA owns 2,295,701 Shares, representing 16.16 % of the capital.
	Victory Capital Management Inc. owns 713,214 Shares, representing 4.7 % of the capital.
	As of the date of this Summary Note, the Company is not being controlled in the sense of Article
	1:14 BCCA.
	Board of directors - The Board of Directors of the Company consists of nine members: (i) Mel
	Management represented by Michel Lussier (non-executive and Chairperson), (ii) Filippo Petti
	(CEO), (iii) Serge Goblet (non-executive), (iv) Chris Buyse (non-executive director), (v) R.A.D.
	Lifesciences BV represented by Rudy Dekeyser (non-executive director), (vi) Hilde Windels
	(independent director), (vii) Maria Koehler (independent director), (viii) Dominic Piscitelli
	(independent director) and (ix) Marina Udier (independent director).
	Statutory auditor - CVBA E&Y Bedrijfsrevisoren-Réviseurs d'Entreprises, having its registered
	office at De Kleetlaan 2, B - 1831 Diegem, Belgium, represented by Carlo-Sébastien d'Addario,
	has been appointed as Statutory Auditor of the Company on 5 May 2020 for a term of three years.
B.2	What is the key financial information regarding the issuer?
	The following tables set out the selected key consolidated historical financial information of Celyad
	as at the dates and for the periods indicated. Unless indicated otherwise, the figures set forth in the
	table below are in EUR thousands.
		31/12/2019	31/12/2020
	Income statement
	Total revenue		6	5
	Gross profit		6	5
	R&D expenses		(25,196)	(21,522)
	General and administrative expenses		(9,070)	(9,315)
	Operation loss		(28,879)	(16,987)
	Financial income/(expense)		239	217
	Loss for the period		(28,632)	(17,204)
	Earnings per share (in EUR)		(2.29)	(1.23)
	Balance sheet
	Intangible assets		39,199	36,171
	Cash and cash equivalent		39,338	17,234
	Total assets		89,836	66,084
	Total equity		45,619	30,994

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	Non-current liabilities	32,395	23,256
	Current liabilities	11,922	11,834
	Total equity and liabilities	89,836	66,084
	Net financial debt	(7,423)	6,376
	Cash flow statements
	Net cash generated from operating activities	(28,202)	(27,665)
	Net cash generated from investing activities	8,987	157
	Net cash generated from financing activities	18,276	5,396
B.3	What are the key risks that are specific to the issuer?

1. • The Company will need substantial additional funding, which may not be available on acceptable terms when needed, if at all. The Company has substantial financial commitments resulting from material agreements (to Celdara, Dartmouth, Horizon), for which the Company will need substantial additional funding.
   • The Company has incurred net losses in each period since its inception and anticipates that it will continue to incur net losses in the future.
   • The Company's drug product candidates are new approaches to cancer treatment that present significant challenges.
   • The Company's drug product candidates are biologics, which are complex to manufacture, and the Company may encounter difficulties in production, particularly with respect to process development or scaling-out of its manufacturing capabilities. If the Company or any of its third- party manufacturers encounters such difficulties, its ability to provide supply of its drug product candidates for clinical trials or its products for patients, if approved, could be delayed or stopped, or the Company may be unable to maintain a commercially viable cost structure.
   • The Company may encounter substantial delays in its clinical trials or may fail to demonstrate safety and efficacy to the satisfaction of applicable regulatory authorities.
   • The Company may be adversely affected by natural disasters and/or global health pandemics (such as COVID-19), and its business, financial conditions and results of operations could be adversely affected.
   • The Company is heavily dependent on the regulatory approval of its product candidates in the United States and Europe, and subsequent commercial success, both of which may never occur.
   • The Company could be unsuccessful in obtaining, maintaining or protecting its intellectual property rights for one or more of its drug product candidates.
   • The Company has not yet finalized its clinical development program for its product candidates. The FDA and comparable foreign regulators may not agree with its proposed protocols for these clinical trials, or may withdraw approvals, which could result in delays or cancellation of the programs.
   • Cell-basedtherapies rely on the availability of specialty raw materials, which may not be available to the Company on acceptable terms or at all.
   • The Company relies on third parties to conduct, supervise and monitor its clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, the Company may not be able to obtain regulatory approval for or commercialize its drug product candidates and its business could be substantially harmed.
2. Key information on the securities

Element	Disclosure requirement

C.1 What are the main features of the securities - An application will be made to admit up to 2,595,777 New Shares to trading on the regulated markets of Euronext Brussels and Euronext Paris under the symbol "CYAD" and with the ISIN code BE0974260896-XBRU as and when the New Shares are placed and subscribed.

Rights attached to the Shares - All New Shares will be issued in euro, in accordance with Belgian law and will be ordinary Shares representing the capital, of the same class as the existing Shares, fully paid up, with voting rights and without nominal value. They will have the same rights as the

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	existing Shares. The New Shares will be profit sharing as from any distribution in respect of which
	the relevant dividend date falls after the date of their issuance.
	Seniority - All Shares represent an equal part of the Company's share capital and have the same
	rank in the event of insolvency of the Company.
	Restriction on the free transferability of the Shares There is no restriction on the free
	transferability of the Shares, other than those applicable by operation of law.
	Dividend policy - The Company has not declared or paid dividends on its Shares in the past. In the
	future, the Company's dividend policy will be determined and may change from time to time by
	determination of the Company's Board of Directors. Any declaration of dividends will be based
	upon the Company's earnings, financial condition, capital requirements and other factors
	considered important by the Board of Directors. Belgian law and the Company's Articles of
	Association do not require the Company to declare dividends. Currently, the Board of Directors of
	the Company expects to retain all earnings, if any, generated by the Company's operations for the
	development and growth of its business and does not anticipate paying any dividends to the
	shareholders in the foreseeable future. As a consequence of all of these factors, there can be no
	assurance as to whether dividends or similar payments will be paid out in the future nor, if they are
	paid, as to their amount.
C.2	Where will the securities be traded
	An application will be made to admit all or part of the New Shares (subject to their placement and
	subscription) to trading on the regulated market of Euronext Brussels and Euronext Paris under the
	symbol "CYAD" and the ISIN code BE0974260896-XBRU. The New Shares will also be traded
	through ADSs on the NASDAQ Global Market under the symbol "CYAD".
C.3	What are the key risks that are specific to the securities

• The market price pf the Shares could be negatively impacted by actual or anticipated sales of substantial numbers of Shares.
• The Company cannot guarantee the extent to which a liquid market for the Shares will be sustained. In the absence of such liquid market for the Shares, the price of the Shares could be impacted negatively.
• The Company has no present intention to pay dividends on its Shares in the foreseeable future.

D. Key information on the admission to trading on a regulated market

Element	Disclosure requirement
D.1	Under which conditions and timetable can I invest in this security?
	The New Shares will be subscribed by investors in the framework of at-the-market ("ATM")
	offerings performed on the Nasdaq market. No offering to the public will take place in Belgium or
	in France or through Euronext markets. ATM offerings will be performed over a limited period of
	time until 2 September 2023.
	Admission to trading - An application will be made to admit all or part of the New Shares on the
	regulated market of Euronext Brussels and Euronext Paris under the symbol "CYAD" and the ISIN
	code BE0974260896-XBRU. The New Shares will also be traded through ADSs on the NASDAQ
	Global Market under the symbol "CYAD". The New Shares should be admitted to trading on
	Euronext Brussels and Euronext Paris on or around the second trading day following the reception
	by the Company of the notifications of subscription issued by Jefferies.
	Dilution - The preferential subscription rights of the existing shareholders has been waived in the
	context of the issuance of the New Shares, they will undergo a dilution of voting rights and dividend
	right. An existing shareholder that holds 1% of the share capital of the Company prior to the
	issuance of the New Shares, who do not subscribe for the New Shares, will, after their issuance, but
	without taking into account the outstanding subscription rights, hold 0.85 % of the share capital of
	the Company.
	Costs in relation to the issuance of the New Shares - The fees and commissions payable by the
	Company to Jefferies with respect to the placement of the New Shares corresponds to 4% of the
	gross proceeds received by the Company. In addition, the aggregate of the administrative, legal, tax
	and audit expenses as well as the other costs in connection with the placement of the New Shares

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