Celyad Oncology SA — Proxy Solicitation & Information Statement 2025

Apr 18, 2025

CELYAD ONCOLOGY, SA Listed limited liability company

Rue André Dumont, 9 1435 Mont-Saint-Guibert

LER Nivelles 0891.118.115

CONVENING LETTER TO THE ORDINARY AND EXTRAORDINARY GENERAL MEETINGS OF SHAREHOLDERS OF 20 MAY 2025

The board of directors has the honor to convene the shareholders and warrant holders of Celyad Oncology, SA (the "Company") to attend the ordinary general meeting to be held successively on 20 May 2025 at 3pm (CET) and 4pm (CET) at the Company's registered office, the agendas of which are given below.

AGENDA OF THE ORDINARY SHAREHOLDERS' MEETING

1. Acknowledgement of the special report of the board of directors prepared in accordance with Article 7:228 of the Companies and Associations Code and the measures proposed by the board of directors therein

Comments on this agenda item: The board of directors requests the general meeting of shareholders to acknowledge the aforementioned report.

2. Decision relating to the continuation of the Company's activities and approval of any possible remedial measures proposed by the board of directors

Proposal of resolution: the general meeting of shareholders resolves, in particular in view of the above-mentioned report, (i) to continue operations of the Company, (ii) to confirm that additional reorganization measures do not seem necessary due to the measures already taken over the last years as indicated in the report and (iii) to allow the board of directors to examine other possible measures and to take them into account in the light of the Company's financial needs.

3. Deliberation on the annual report of the board of directors for the financial year ended on 31 December 2024 and on the report of the statutory auditor for the financial year ended on 31 December 2024

Comments on this agenda item: The board of directors requests the general meeting of shareholders to take note of the board of directors' annual report for the financial year ended on 31 December 2024 and the statutory auditor's report for the financial year ended on 31 December 2024.

• 4. Deliberation and approval of the Company's remuneration report, as presented by the nomination and remuneration committee and as included in the annual report Proposal of resolution: The general meeting of shareholders decides to approve the remuneration report prepared by the board of directors, as presented by the nomination and remuneration committee and as included in the annual report.
• 5. Deliberation pursuant to Article 7:91 of Companies and associations Code on the determination of the variable remuneration of the CEO

Proposal of resolution: Based on Article 7:91 of the Companies and Associations Code, the general meeting confirms that the calculation of the variable remuneration of the CEO, exceeding 25% of the annual base remuneration, can be done on the basis of criteria evaluated on periods shorter than two or three years.

6. Deliberation on the consolidated financial statements for the financial year ended on 31 December 2024, as included in the annual report.

Comments on this agenda item: The board of directors requests the general meeting of shareholders to acknowledge the consolidated financial statements for the financial year ended on 31 December 2024.

7. Deliberation and approval of the statutory annual accounts for the financial year ended on 31 December 2024 and the allocation of the result as proposed by the board of directors in its annual report

Proposal of resolution: The general meeting of shareholders decides to approve the annual accounts for the financial year ended on 31 December 2024 and the allocation of the result as proposed by the board of directors in its annual report.

8. Discharge to the directors

Proposal of resolution: The general meeting of shareholders decides to grant discharge to the following directors for the exercise of their mandate during the financial year ended on 31 December 2024:

• − Matthew Kane ;
• − Serge Goblet;
• − Dominic Piscitelli;
• − Marina Udier Blagovic;
• − Christopher LiPuma;
• − Ami Patel Shah;
• − Andrea Gothing;
• − Jonathan James;
• − Sage Mandel;
• − HILDE WINDELS BV, represented by Hilde Windels, Chairperson;
• − CFIP CLYD LLC, represented by Michel Lussier.

9. Discharge to the statutory auditor

Proposal of resolution: The general meeting of shareholders decides to grant discharge to the statutory auditor VCBA BDO Bedrijfsrevisoren – Réviseurs d'entreprises, having its registered office at 1930 Zaventem, The Corporate Village, Da Vincilaan 9, boite E.6, Belgium, duly represented by Bert Kegels and Christophe Pelzer, for the exercise of its mandate during the financial year ended on 31 December 2024.

10. Deliberation on the proposal of the board of directors to renew the mandate of director of Marina Udier Blagovic for 2 years

Proposal of resolution: The general meeting of shareholders decides to renew the mandate of Marina Udier Blagovic as director of the Company for 2 additional years, i.e. until the ordinary general meeting approving the accounts closed on 31 December 2026.

11. Power of attorney

Proposition of resolution: The general meeting of shareholders decides to grant a proxy to Mrs. An Phan, Head of Legal, and/or F&C Consulting SRL, represented by M. David Georges, VP Finance and Administration, and/or Me Adrien Lanotte, and/or to any lawyer of the firm Harvest Avocats, or to each member of the board of directors of the Company, acting alone, each with power of substitution, in order to issue, execute and sign all documents, instruments, steps and formalities and to give all necessary or useful instructions to execute the aforementioned decisions, including, but not limited to, the formalities for filing with the National Bank of Belgium the annual accounts and the consolidated annual accounts closed on 31 December 2024, the annual reports and the auditor's report relating thereto and the realization of the necessary publication formalities, including the publication in the annexes to the Belgian Official Gazette of the abovementioned decisions.

AGENDA OF THE EXTRAORDINARY SHAREHOLDER'S MEETING

1. Formal reduction of the share capital by absorption of losses

Proposal of resolution: The meeting decides to reduce the share capital by absorption of the losses by an amount of six million four hundred eleven thousand eight hundred twelve euros and eighty-seven cents (€6,411,812.87), to reduce it from eight million two hundred sixteen thousand one hundred fiftyfour euros and sixty-three cents (€8,216,154.63) to one million eight hundred four thousand three hundred forty-one euros and seventy-six cents (€1,804,341.76). The reduction of the share capital shall be done without cancellation of shares.

2. Acknowledgement of the effective realisation of the reduction of the share capital

Proposal of resolution: The meeting acknowledges and requests me, as a notary, to authentically acknowledge the effective realisation of the above reduction of the share capital by an amount of six million four hundred eleven thousand eight hundred twelve euros and eighty-seven cents (€6,411,812.87) and so that the share capital is thus effectively reduced to one million eight hundred four thousand three hundred forty-one euros and seventy-six cents (€1,804,341.76).

3. Amendment of Article 5 of the Articles of Association

Proposal of resolution: In order to bring the Articles of Association into line with the above decisions, the meeting resolves to amend and replace Article 5 of the Articles of Association with the following text: "The company's share capital is set at one million eight hundred four thousand three hundred forty-one euros and seventy-six cents (€1,804,341.76), represented by forty-one million four hundred twenty-eight thousand five hundred seventy-two (41,428,572) shares which do not contain a face value, each representing an equal share of the share capital."

4. Power of attorney

Proposal of resolution: The meeting decides to grant a proxy to Mrs. An Phan, head of legal, F&C Consulting SRL, represented by M. David Georges, VP Finance and Administration, and/or Me Adrien Lanotte, and/or to any lawyer of the firm Harvest Avocats, acting alone, each with power of substitution, in order to issue, execute and sign all documents, instruments, steps and formalities and to give all necessary or useful instructions to execute the aforementioned decisions and the realization of the necessary publication formalities, including the publication in the annexes to the Belgian Official Gazette of the abovementioned decisions, and to the undersigned notary, or to any other notary and/or collaborator of "Berquin Notaires", in order to give them all powers to draft the text of the coordination of the articles of association of the Company, sign it and deposit it in the electronic database provided for this purpose, in accordance with the legal provisions on the matter.

RECOMMANDATION

The board of directors is recommending that the shareholders approve each of the foregoing proposals.

QUORUM AND MAJORITY

Quorum requirement: No quorum is required for the agenda items of the ordinary shareholders' meeting. The agenda items of the extraordinary shareholders' meeting are subject to a meeting to be held in front of a notary public. To validly deliberate on items 1 to 3 of the agenda of the extraordinary general meeting, a quorum of at least half of the share capital shall be present or represented. If this quorum requirement is not met, a new meeting of the extraordinary general meeting with the same agenda shall be held on 17 June 2025 at 3pm (CET), which may validly deliberate without the abovementioned quorum being met.

Vote and majority: Without prejudice to the shares fully subscribed and registered since at least two years without interruption in the name of the same shareholder in the shareholder registry and that benefit of a double voting right, each share gives right to one vote. The proposed resolutions of the ordinary shareholders' meeting shall be adopted by a simple majority of the votes validly casted by the shareholders. The proposed resolutions referred to in the agenda of the extraordinary general meeting shall be adopted if approved by a majority of three quarters of the votes validly casted by the shareholders, except for the resolution mentioned under item 4 of the agenda which requires the adoption of a simple majority of the votes. Pursuant to Article 7:135 of the Companies and Associations Code, the holders of warrants have the right to participate to the shareholders' meetings, but only with a consultation right.

PARTICIPATION IN THE MEETING

Covid-19 measures

The Company will grant access to the meeting room only to the extent permitted by the authorities on the meeting's date. The Company is monitoring the situation closely and will disclose all relevant information and additional measures impacting the shareholders' meeting on its website. However, the Company strongly encourages the shareholders to limit their physical presence and to vote through proxy (pursuant to the procedure described below).

Admission requirements

The right to participate in the general meetings of shareholders and to vote is subject to the prior accounting registration of the shares under the shareholder's name on 6 May 2025 at midnight (Belgian time) (the "Record Date"), either by way of registration in the Company's share register, or either by way of registration in book entry form in an account held with a settlement institution or a certified account holder, without taking into account the number of shares held by the shareholder at the day of the general meeting.

The day and time referred to above shall constitute the Record Date. Only persons who are shareholders on the Record Date are entitled to attend and vote at the general meeting.

A certificate is delivered to the shareholder by the settlement institution or certified account holder which certifies the number of dematerialised shares registered in its accounts under the name of the shareholder on the Record Date, for which the shareholder has expressed his/her/its intention to participate in the general meeting.

The shareholder indicates his/her/its intention to participate in the general meetings by 14 May 2025 at the latest. This must be done by email to investors@celyad.com, or by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert.

The holders of warrants have the right to attend the general meeting, subject to them fulfilling the shareholders' admission conditions.

Right to include items on the agenda and to submit proposals for decisions

In accordance with Article 7:130 of the Companies and Associations Code, one or more shareholders holding together at least 3% of the share capital may request the inclusion of items on the agenda to be addressed at the general meeting and request the submission of decisions' proposals concerning items to be addressed or included on the agenda.

The shareholder or shareholders exercising this right must, in order for their request to be examined at the general meeting, satisfy the following two conditions:

• prove that they hold the abovementioned required percentage on the date of their request (either by way of a certificate mentioning the registration of the corresponding shares on the Company's share register, or by way of an attest of a settlement institution or a certified account holder setting out the number of corresponding dematerialised shares registered in its accounts under the name of the shareholder); and
• still be a shareholder for up to 3% of the Company's share capital on the Record Date.

Items to be included on this agenda and/or decisions' proposals must be sent to the Company on 28 April 2025 at the latest by email to investors@celyad.com, or by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert.

The Company will acknowledge receipt of the requests sent by email or by mail to the address indicated by the shareholder within 48 hours after receipt.

The revised agenda will be published on 5 May 2025 at the latest (on the Company's website at the address www.celyad.com, in the Belgian Official Gazette and in the press) if one or more requests to include new items or proposals for decisions on the agenda have been received within the aforementioned deadline.

Further information relating to the abovementioned rights and the modalities for exercising them are available on the Company's website (www.celyad.com).

Right to ask questions

Shareholders may ask questions exclusively in writing before the meeting, concerning the report of the board of directors or the agenda of the meeting. The Company will answer the questions during the meeting.

The questions can be sent prior to the general meeting by email to the address investors@celyad.com or by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert.

Those questions must be received by the Company on 14 May 2025 at 17h00 (CET) at the latest.

Further information relating to the abovementioned right and the modalities for exercising them are available on the Company's website (www.celyad.com).

Proxies

Any shareholder who wishes to vote at the meeting shall be represented by the proxy holder determined by the Company.

Shareholders wishing to be represented must use the proxy form established by the board of directors. The proxy form may be obtained on the Company's website (www.celyad.com) or upon request at the Company's registered office, or by email to investors@celyad.com.

The original form signed on paper form must be received by the Company on 14 May 2025 at 17h00 (Belgian time) at the latest. This form may be communicated to the Company by mail marked for the attention of Celyad Oncology SA, Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert, or by email to investors@celyad.com provided that the last communication is signed by electronic signature, in accordance with applicable Belgian legislation. Shareholders are invited to follow the instructions set out in the proxy form in order to be validly represented at the meeting.

Shareholders wishing to be represented must comply with the registration and confirmation procedure described above.

Available documents

All documents concerning the general meetings that are required by law to be made available to shareholders may be consulted on the Company's website (www.celyad.com) as from 18 April 2025.

As from the same date, shareholders have the right to consult these documents on business days and during normal office hours, at the Company's registered office and/or, upon display of their securities, obtain copies of these documents free of charge.

Requests for copies may also be made, free of charge, by mail (writing) marked for the attention of Mrs. An Phan, Head of Legal, Rue André Dumont 9, B-1435 Mont-Saint-Guibert, or by email to investors@celyad.com

The board of directors

Annexes