Document:

EX-4.19

 Exhibit 4.19 

Certain portions of this exhibit have been omitted because they are not 

material and the registrant customarily and actually treats 

that information as private or confidential. 

AMENDED AND RESTATED EMPLOYMENT AGREEMENT 

THIS AMENDED AND RESTATED EMPLOYMENT AGREEMENT (the “Agreement”) is made as of 24 March, 2021 (the “CEO Start
Date”), between Celyad ONCOLOGY SA (“Celyad”), Celyad Inc., a Delaware corporation (the “Corporation”), and Filippo Petti (the “Employee”) (the Employee, Celyad and the Corporation, the
“Parties”). This Agreement amends, restates, and supersedes in all respects the employment agreement between the Company and the Executive with an effective date of 30 July 2018 (the “Former Employment
Agreement”). The Parties hereby acknowledge and agree that Section 11(a) of the Former Employee Agreement (the “Non-Competition Restriction”) was supported by sufficient
consideration at the time it was entered into and remains in full effect as amended and restated in Section 9(a) herein. The Parties agree that, in any event, the Noncompetition Restriction, as amended and restated in Section 9(a) herein,
is independently supported by (i) the Employee’s Base Salary is $ (ii) the Employee’s target bonus percentage to . The Parties hereby confirm that the Noncompete Consideration would not be provided absent the Employee’s execution
of and compliance with Section 9(a) of this Agreement. The Parties further expressly acknowledge and agree that the Noncompete Consideration is, in each case, mutually-agreed upon between the Parties and is fair and reasonable consideration for
Section 9(a) of this Agreement. 
 Introduction 

The Corporation is engaged in research and development of biological pharmaceutical products or medical devices, solely or in combination (the
“Business”). 
 The Corporation is a wholly owned subsidiary of Celyad, a publicly listed company on Euronext Brussels,
Euronext Paris and Nasdaq, with registered offices in Mont-Saint-Guibert, Rue Edouard Belin 2, Belgium; 
 The Parties intend that the
Employee will be an employee of Celyad; 
 Celyad and its subsidiaries and affiliates, including the Corporation, comprise the
“Celyad Group”; 
 The Corporation and Celyad wish to retain the services of Employee, subject to such travel requirements
as the Corporation or Celyad may reasonably request. 
 NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties agree as follows: 
 1. Employment. As of the CEO Start Date, the Employee will be employed
by Celyad as Chief Executive Officer (the “CEO”). The Employee shall be responsible for such duties as may be reasonably assigned from time to time by the Board of Directors of Celyad (the “Board,” and the
performance of such duties, the “Services”). The Parties acknowledge and accept the Employee’s employment upon the terms and conditions hereinafter set forth. Notwithstanding anything in this Agreement to the contrary, nothing
in this Agreement shall be construed to alter the at-will nature of the Employee’s employment, nor shall anything in this Agreement or any benefit program be construed as providing the Employee with a
definite term of employment. 

 2. Compensation. 

(a) In consideration for the Services, Celyad shall pay Employee a salary at the annual rate of [***]. The Base Salary may be adjusted from
time to time by Celyad. The base salary in effect from time to time is the “Base Salary.” Payments of Base Salary shall be made in accordance with Celyad’s payroll practices. 

(b) Employee shall be eligible for a target annual bonus equal to [***] of the Base Salary, subject to Celyad’s bonus plan in effect from
time to time. 
 (c) The Employee shall be eligible to participate in Celyad’s warrant plans as set forth in this subsection
(c) and in any other written agreements, in the form provided by Celyad, governing the warrants as are provided by Celyad. For the avoidance of doubt, Employee understands that under Belgian law, stock warrant plans are proposed by the Celyad
Board and approved by a General Meeting of Celyad’s shareholders and the amount of warrants allocated to employees under an approved warrant plan is determined exclusively by the Celyad Board. 

(d) All compensation paid to Employee shall be subject to taxes and other withholdings as required by law. The Employee is solely responsible
for the payment of all taxes related to the warrants. 
 3. Expenses and Travel. 

Employee shall be entitled to receive prompt reimbursement for all reasonable, documented expenses incurred by Employee in performing the
Services hereunder, including all reasonable expenses of travel and living while away from home, provided that such expenses are incurred and accounted for in accordance with the policies and procedures established by Celyad. 

4. Medical Vacation and Other Benefits. 

Employee shall be entitled to receive certain benefits applicable to employees of the Celyad Group as determined by Celyad and subject to
applicable law, which benefits currently include dental and health care plans, in each case in accordance with the terms of such plans. In the event that Employee elects not to receive medical benefits from the Corporation, Employee may, in the
Corporation’s or Celyad’s sole discretion, be eligible to receive a monthly cash payment in an amount equal to the premium the Corporation would have contributed toward individual medical insurance coverage in the United States for
Employee. 
 Employee shall receive twenty (20) days of vacation annually, in addition to all legal U.S. Federal holidays, both paid at
the expense of Celyad. Such vacation shall be subject to Celyad and/or Corporation policy in all respects. In the absence of such policy, such vacation shall accrue ratably over the course of the year and shall not roll over from year to year. 

  
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 Employee shall be eligible for the Corporation’s 401 (k) plan on the first day of the
first month following Employee’s first day of employment. Currently, on an annual basis, the Corporation pays, at no additional cost to the Employee, a contribution equivalent to of the Employee’s Base Salary, subject to Employee’s
employment with the Corporation on the date such contribution is made. 
 Notwithstanding this foregoing Section 4, any member of the
Celyad Group may alter the terms and conditions of any employee benefit plan, program or agreement, or eliminate any such plan, program or agreement, at any time in such entity’s discretion. 

5. Performance of Services. During the term of this Agreement, Employee shall use Employee’s best efforts to promote the interests
of the Celyad Group and shall devote Employee’s full time and efforts to its Business and affairs in an honest and ethical manner in compliance with this Agreement and all applicable laws, rules and regulations, promulgated from time to time,
applicable to the Business, including the federal, state and municipal non-discrimination laws in the United States, rules and regulations. Except for vacation, sick time and other Company-approved leaves of
absence subject to Company policies, the employee is expected to and shall work 40 hours per week at minimum. Without limiting the foregoing, the Employee shall not engage in any other activity that could reasonably be expected to interfere with the
performance of Employee’s duties, responsibilities or Services hereunder. 
 6. Employee Representations. Employee represents and
warrants to the Celyad Group that Employee is qualified to perform the Services and that neither Employee’s execution of the Agreement nor Employee’s performance of such Services is limited or prohibited by, and will not cause a conflict
of interest or breach of, any law, regulation, agreement, understanding, order, judgment, decree or other instrument, contract, or document to which Employee is a party or subject, including without limitation any confidentiality or restrictive
covenant agreement with any prior employer. 
 7. Conflicts of Interest. Employee confirms that Employee has advised the Celyad Group
in writing, prior to the date of signing this Agreement, of any current relationship with third parties, including competitors of the Celyad Group. The Chief Executive Officer of Celyad and Employee will review each of those relationships and
determine together which ones need to be terminated due to a conflict of interest, or prohibition of Employee carrying out the terms of this Agreement, or which would present a significant risk of disclosure of Confidential Information. 

8. Exclusivity. For the duration of this Agreement, Employee shall provide Services exclusively to the
Celyad Group and Employee shall not seek, accept or perform any consulting or other services (whether or not for compensation) without the specific and written approval of the Chief Executive Officer of Celyad, or his or her designee. 

9. Restrictive Covenants. The “Termination Date” shall be the last day of the Employee’s employment with the
Corporation (or with Celyad, whichever ends later), regardless of the reason for the termination. During the Employee’s employment with the Corporation (and/or Celyad) and for a period of twelve (12) months after the Termination Date (the
“Restricted Period”), Employee will not, directly or indirectly, whether as an officer, director, employee, consultant, contractor, equity owner, agent or otherwise: 

  
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 (a) Engage, provide services to or participate in any cell therapy company or business
activity developing CAR T therapies focused on NKG2D, B7H6 and/or NKp (including without limitation NKp30, NKp40, NKp44) or any other business activity concerning CAR T therapies. Nothing in this Section 9(a) shall be deemed to prohibit
Employee from investing in any company engaged in such business, the stock of which is available in a public securities market; provided, however, that Employee shall not own in excess of five percent (5%) of the total issued and outstanding stock
of such company. Notwithstanding any other provision of this Agreement, this Section 9(a) shall become effective ten (10) business days following the date this Agreement is provided to the Employee. The Employee has been advised by the
Company that the Employee has the right to consult with counsel prior to signing this Agreement.     
 (b) Solicit,
recruit, endeavor to entice away, hire, attempt to hire, or otherwise materially interfere with the business relationship of any person or entity who is, or was within the twelve (12) month period immediately prior to the Termination Date was,
employed or engaged (whether as an employee, independent contractor or otherwise) by any member of the Celyad Group. 
 (c) Solicit, recruit,
endeavor to entice, or do business with any person or entity who is, or within the twelve (12) month period immediately prior to the Termination Date was, a customer, client or supplier of any member of the Celyad Group. 

10. Non disparagement. During and after Employee’s employment with the Corporation and/or Celyad, Employee agrees not to make any
disparaging statements concerning the Corporation or any of its affiliates (including Celyad), products, services or current or former officers, directors, shareholders, employees or agents, except in the context of performing Employee’s
legitimate duties to the Corporation or Celyad during Employee’s employment with the Corporation and Celyad. The Corporation agrees to instruct its Board not to, during and after Employee’s employment with the Corporation, make any
disparaging statements concerning the Employee. 
 11. Confidentiality of Information. Employee recognizes and acknowledges that the
trade secrets of the Celyad Group and all other confidential and proprietary information of the Celyad Group, including information of a business, financial or other nature, including without limitation, scientific and technical information and
improvements thereon, data from or results of clinical trials, patient information, lists of the Celyad Group’s actual and prospective customers, financial information and business and marketing plans, as they exist from time to time
(collectively, the “Confidential Information”), are a valuable and unique asset of the Celyad Group. Employee therefore agrees that Employee will not, either during or after the Termination Date, disclose any Confidential
Information concerning any entity in the Celyad Group, to any person, firm, corporation, association or other entity, or use any such Confidential Information, for any reason whatsoever. The term “Confidential Information” shall not
include any information that (i) is or becomes publicly available through no direct or indirect action of the Employee; or (ii) is required to be disclosed by a court of competent jurisdiction or pursuant to any arbitration, provided
that Employee first gives notice of such disclosure requirement to the Corporation and Celyad. Employee shall not at any time, make any use whatsoever, directly or indirectly, of Confidential Information, except as required in connection with
the performance of Services. 

  
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 12. Injunctive Relief. The Employee acknowledges that a breach of any of the
provisions contained in Sections 9, 10 or 11 would result in irreparable injury to the Celyad Group for which there may be no adequate remedy at law and that, in the event of an actual or threatened breach by the Employee of the provisions of
Sections 9, 10 or 11, any member of the Celyad Group, shall be entitled to pursue and obtain injunctive relief from a court of competent jurisdiction restraining Employee from doing any act prohibited thereunder. Nothing contained herein shall be
construed as prohibiting Celyad Group or the Corporation, as appropriate, from pursuing any other remedies available to it for such breach or threatened breach, including the recovery of any monetary damages to which it would be entitled under the
law. In the event that any provision of Sections 9, 10 or 11 is held to be unenforceable as a result of it being too broad, including in terms of time or geographical extent, Employee agrees that the court can adapt and limit this Section so as to
make the provisions hereof enforceable to the fullest extent permissible. The post-employment restricted periods in Section 9 shall be extended by each day that the Employee is in breach of any provision of Section 9. 

13. Rights in Celyad Group Property; Inventions. The Employee hereby recognizes the Celyad Group’s proprietary rights in the
tangible and intangible property of the Celyad Group and acknowledges that the Employee will not obtain or acquire through such employment any personal property rights in any of the property of any member of the Celyad Group, including but not
limited to, any writing, communications, manuals, documents, instruments, contracts, agreements, files, literature, data, technical information, know-how, secrets, formulas, products! methods, procedures,
processes, devices, apparatuses, trademarks, trade names, trade styles’ service marks, logos, copyrights, patents, or other matters which are the property of any member of the Celyad Group. The Employee agrees that during his employment by the
Corporation and/or Celyad, any and all discoveries, inventions, improvements and innovations (including all data and records pertaining thereto), whether or not patentable, copyrightable or reduced to writing, which the Employee may have conceived
or made, or may conceive or make, either alone or in conjunction with others and whether or not during working hours or by the use of the facilities of the Corporation or Celyad, which are related or in any way connected with the Business of the
Corporation, Celyad or any of their affiliates, are and shall be the sole and exclusive property of the Corporation and Celyad. The Employee shall promptly disclose all inventions to the Corporation and Celyad, shall execute at the request of the
Corporation or Celyad any assignments or other documents the Corporation or Celyad may deem necessary to protect or perfect its rights therein, and shall assist the Corporation and Celyad, at the Corporation’s or Celyad’s expense, in
obtaining, defending and enforcing the Corporation’s rights therein. The Employee hereby assigns, sets over and transfers to the Corporation and Celyad all of his right, title and interest in and to any inventions and other intellectual
property rights. The Employee hereby appoints the Corporation and Celyad as his attorneys-in-fact to execute on his behalf any assignments or other documents reasonably
necessary by the Corporation or Celyad to protect or perfect its or their rights to any inventions. 
 14. Protected Disclosures.
Employee understands that nothing contained in this Agreement limits Employee’s ability to communicate with any federal, state or local governmental agency or commission, including to provide documents or other information, without notice to
the Corporation and/or Celyad. Employee also understands that nothing in this Agreement limits Employee’s ability to share compensation information concerning Employee or others, except that this does not permit Employee to disclose
compensation information concerning others that Employee obtains because Employee’s job responsibilities require or allow access to such information. 

  
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 15. Defend Trade Secrets Act of 2016. Employee understands that pursuant to the
federal Defend Trade Secrets Act of 2016, Employee shall not be held criminally or civilly liable under any federal or state trade secret law for the disclosure of a trade secret that (a) is made (i) in confidence to a federal, state, or
local government official, either directly or indirectly, or to an attorney; and (ii) solely for the purpose of reporting or investigating a suspected violation of law; or (b) is made in a complaint or other document filed in a lawsuit or
other proceeding, if such filing is made under seal. 
 16. Compensation Upon Termination of Employment for Any Reason. In connection
with Employee’s termination for any reason, Celyad shall pay the Employee any (i) base salary; (ii) unused vacation; and (iii) unreimbursed expenses (subject to the Corporation’s or Celyad’s expense policy), in each
case ((i) through (iii)) accrued through the Termination Date (the obligations described in (i) through (iii), the “Accrued Obligations”). 

17. Termination by Celyad without Cause or by the Employee with Good Reason. 

(a) Celyad (which, for the purposes of Sections 17 through 19, includes the Corporation) shall have the right to terminate the Employee’s
employment without Cause. Celyad will endeavor to, but is not required to, provide the Employee with 30 days advance notice of such a termination. Notwithstanding any such 30-day notice period, Celyad may
subsequently accelerate the Employee’s Termination Date. 
 (b) If Celyad terminates the Employee’s employment without Cause, or if
the Employee terminates the Employee’s employment with Good Reason, and in either case subject to the Release Requirement, Celyad shall pay the Employee nine (9) months of the Employee’s final Base Salary rate as of the Termination
Date and the Health Benefit (as defined below), (the “Severance Pay”). The nine (9) months following the Termination Date is the “Severance Period” 

(i) The “Health Benefit” means, if elected by the Employee under 29 U.S.C. § 1161 et seq. (commonly known as
“COBRA”), continuation of group health plan benefits to the extent authorized by and consistent with COBRA, with the cost of the regular premium for such benefits shared in the same relative proportion by the Company and the
Employee as in effect on the Termination Date until the earliest of (i) the end of the Severance Period; (ii) the date the Employee becomes eligible for health benefits through another employer or (iii) the date the Employee otherwise
becomes ineligible for COBRA. 
 (ii) The Severance Pay shall be payable in installments on Celyad’s regular payroll dates following
the Termination Date, but Celyad (or Celyad, as applicable) shall not be required to begin paying any Severance Pay until its first payroll date after the Release Requirement has been fulfilled. The “Release Requirement” means the
Employee’s execution, return and nonrevocation, in each case with the time periods required by the Release but in no event later than 30 days after the Termination Date (or 60 days in the event of a group layoff under the Older Workers’
Benefits Protection Act), of a separation agreement in a form provided by the Celyad Group containing, among other terms, a release of claims against the Celyad Group and related persons and entities (the “Release”). In no event will the
Release include any additional post-employment noncompetition or nonsolicitation covenants that are not included in this Agreement. 

  
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 (c) For purposes of this Agreement, “Good Reason” shall mean (i) a
material reduction in Employee’s Base Salary or target annual bonus other than a general reduction in Base Salary or target annual bonus that affects all similarly situated employees in substantially the same proportions; (ii) a relocation
of Employee’s principal place of employment by more than 60 miles; or (iii) a material, adverse change in Employee’s title, authority, duties, or responsibilities (other than temporarily while Employee is physically or mentally
incapacitated or as required by applicable law). Before a termination by the Employee for Good Reason, the Employee must (i) reasonably determine in good faith that a “Good Reason” condition has occurred; (ii) notify the Company
in writing of the first occurrence of the Good Reason condition within 60 days of the first occurrence of such condition; (iii) cooperate in good faith with the Company’s efforts, for a period not less than 30 days following such notice
(the “Cure Period”), to remedy the condition and notwithstanding such efforts, the Good Reason condition continues to exist; and (v) terminate his employment within 60 days after the end of the Cure Period. If the Company cures
the Good Reason condition during the Cure Period, Good Reason shall be deemed not to have occurred. 
 18. Termination Upon Death and
Disability. 
 (a) This Agreement may be terminated immediately due to Employee’s death or Disability without any Severance Pay.

 (b) “Disability” shall mean a physical or mental impairment that substantially prevents Employee from performing
Employee’s duties hereunder and that has continued for either (i) one hundred eighty (180) consecutive days or (ii) any one hundred eighty (180) days within a consecutive three hundred sixty (360) day period. Any
dispute as to whether or not Employee is disabled within the meaning of the preceding sentence shall be resolved by a physician reasonably satisfactory to Celyad, and the determination of such physician shall be final and binding upon both Employee
and Celyad. Notwithstanding anything to the contrary in this Section, the inability of Employee to perform the Services, with or without a reasonable accommodation, upon completion of a medical leave of absence of one hundred eighty
(180) consecutive days shall constitute Employee’s Disability. 
 19. Termination by Celyad for Cause; Termination by Employee
without Good Reason. 
 (a) Celyad shall have the right to terminate Employee’s employment for Cause immediately upon written
notice, with the Termination Date occurring as specified in such notice from Celyad. For purposes of this Agreement, “Cause” shall mean (i) conviction, commission of or entering a plea of guilty or nolo contendere to any
felony, or a crime involving dishonesty or moral turpitude; (ii) willfully engaging in conduct materially injurious, or reasonably likely to cause material injury, to any member of the Celyad Group; (iii) the material breach of this
Agreement by Employee or the Employee’s breach of any other restrictive covenant obligation Employee has to any member of the Celyad Group; (iv) Employee’s gross negligence, or willful and deliberate failure to perform Employee’s
duties, or (v) Employee’s failure to adhere to or 

  
 7 

 
comply with any material written policies or procedures of the Celyad Group, including but not limited to the code of conduct or those pertaining to expense reimbursement, harassment,
discrimination or retaliation, conflict of interest, or the prohibition of insider trading. Before a termination for Cause under (iii)—(v) above, and if the Employee’s breach or violation is curable, Celyad shall provide Employee with
written notice and thirty (30) days from the delivery of such notice to cure the conduct, breach or violation (the “Cure Period”), provided that Employee shall not be entitled to more than two Cure Periods in any twelve-month
period. 
 (b) Employee shall have the right to terminate Employee’s employment without Good Reason upon thirty days’ written
notice to Celyad. If Employee provides such notice, Celyad may accelerate the date of Employee’s termination without such acceleration itself constituting a termination by Celyad under this Agreement. 

(c) For the avoidance of doubt, in the event of termination of employment by Celyad for Cause, a termination due to death or Disability or a
termination by Employee without Good Reason, Employee will be entitled only to the Accrued Obligations, and will not be entitled to any Severance Pay. 

20. Enforceability; Severability. This Agreement shall be interpreted in such a manner as to be effective and valid under applicable
law, but if any provision hereof shall be prohibited or invalid under any such law, such provision shall be ineffective to the extent of such prohibition or invalidity, without invalidating or nullifying the remainder of such provision or any other
provisions of this Agreement, If any one or more of the provisions contained in this Agreement shall for any reason be held to be excessively broad as to duration, geographical scope, activity or subject, such provisions shall be construed by
limiting and reducing it or them so as to be enforceable to the maximum extent permitted by applicable law. 
 21. Governing Law;
Jurisdiction. This Agreement shall be construed in accordance with and governed by the laws of the State of New York without giving effect to principles of conflicts of laws. To the extent permitted by Section 22 (Arbitration), including
without limitation the enforcement by the Corporation or Celyad of any of Employee’s restrictive covenant obligations, the state and federal courts located in New York, New York shall have exclusive jurisdiction and exclusive venue over any
controversy or claim arising out of the Employee’s employment or the termination of that employment. 
 22. Arbitration. Any
controversy or claim arising out of or relating to this Agreement or the breach thereof or otherwise arising out of the Employee’s employment or the termination of that employment (including, without limitation, any claims of unlawful
employment discrimination whether based on age or otherwise) shall, to the fullest extent permitted by law, be settled by arbitration, before a single arbitrator, in any forum and form agreed upon by the parties or, in the absence of such an
agreement, under the auspices of the American Arbitration Association (“AAA”) in New York, New York in accordance with the Employment Arbitration Rules of the AAA, including, but not limited to, the rules and procedures applicable
to the selection of arbitrators. In the event that any person or entity other than the Parties may be a party with regard to any such controversy or claim, such controversy or claim shall be submitted to arbitration subject to such other person or
entity’s agreement. Judgment upon the award rendered by the arbitrator may be entered in any court having jurisdiction thereof. This Section shall be specifically 

  
 8 

 
enforceable. Notwithstanding the foregoing, this Section shall not preclude either party from pursuing a court action for the sole purpose of obtaining a temporary restraining order or a
preliminary injunction in circumstances in which such relief is appropriate, including to enforce any confidentiality or restrictive covenant obligation of the Employee, provided that any other relief shall be pursued through an arbitration
proceeding pursuant to this Section. The Corporation, Celyad and Employee each shall be responsible for their own attorneys’ fees and costs, except that Celyad shall bear the cost of the arbitration fees in such proceeding. 

23. Section 409A. It is intended that the benefits provided under this Agreement shall comply with the provisions of
Section 409A of the Internal Revenue Code (“Section 409A”) or qualify for an exemption to Section 409A, and this Agreement shall be construed and interpreted in accordance with such intent. Any payments that qualify
for the “short term deferral” exception or another exception under Section 409A shall be paid under the applicable exception. Each payment provided under this Agreement shall be treated as a separate payment for Section 409A
purposes. No member of the Celyad Group (or its affiliates), the Board, or any employee, officer or director of the Celyad Group (or its affiliates) shall be held liable for any taxes, interest, penalties or other monetary amounts owed by the
Employee as a result of this Agreement. 
 24. Notices. Any notice or other communication given pursuant to this Agreement shall be in
writing and shall be personally delivered, sent by overnight courier or express mail, or mailed by first class certified or registered mail, postage prepaid, return receipt requested to the parties at their respective addresses set forth on the
signature page hereof, or to such other address as the parties shall have designated by notice to the other parties. 
 25. Amendment;
Waiver. No provision of this Agreement may be amended, modified, waived or discharged unless such amendment, modification, waiver or discharge is agreed to in writing and signed by the parties. No waiver by either party hereto at any time of any
breach by the other party hereto of, or compliance with, any condition or provision of this Agreement to be performed by such other party shall be deemed a waiver of similar or dissimilar provisions or conditions at the same or at any prior or
subsequent time. 
 26. Successors and Assigns. This Agreement shall inure to the benefit of and be binding upon the Corporation,
Celyad, their successors and assigns, and the Employee, Employee’s heirs and legal representatives. Employee acknowledges that the Services are personal and that Employee may not assign this Agreement. 

27. Entire Agreement. This Agreement and any other confidentiality or restrictive covenant obligations Employee has to any member of the
Celyad Group constitutes the entire agreement between the parties with respect to the subject matter hereof and supersedes any and all prior agreements, arrangements and understandings, written or oral, relating to the same subjects covered by this
Agreement, including the Former Employment Agreement. 
 28. Counterparts. This Agreement may be executed in multiple counterparts,
each of which shall be deemed an original, but all of which together shall constitute one and the same agreement. The facsimile or electronic signature of either party to this Agreement for purposes of execution or otherwise, is to be considered as
an original signature, and the document transmitted is to be considered to have the same binding effect as an original signature on an original document. 

  
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 IN WITNESS WHEREOF, the parties have executed this amended and restated Agreement as of the
date first above written. 
  

			
	CELYAD ONCOLOGY SA
		
	Address:	 	
	Celyad Oncology S.A.
	Axisparc Business Center
	Rue Edouard Belin, 2
	B-1435 Mont-Saint-Guibert, Belgium
	
	 /s/ Michel Lussier

By: Michel Lussier

	Title: Chairman of the Board
	
	 /s/ Dominic Piscitelli

By: Dominic Piscitelli

	Title: Director
	
	CELYAD INC.
	
	 /s/ Philippe Dechamps

By: Philippe Dechamps

	Title: Chief Legal Officer

  
 10 

 
	
	Employee
	
	 /s/ Filippo Petti

Filippo Petti

	
	Address:
	12, Fox Hollow Lane – Old Westbury, NY 11568, USA

  
 11EX-4.20

 Exhibit 4.20 

CONFIDENTIAL 
 Certain portions
of this exhibit have been omitted because they are not 
 material and the registrant customarily and actually treats 

that information as private or confidential. 

R&D COLLABORATION AND LICENSE AGREEMENT 

This R&D collaboration and license agreement is made on the Effective Date between: 

 

	(1)	 Celyad SA, having its registered office at Edouard Belin 2, 1435 Mont-Saint-Guibert (Belgium),
registered with the register of legal entities under number 0891.118.115 (together with its Affiliates referred to as “Celyad”); 

and 
  

	(2)	 Horizon Discovery Limited, having its registered office at Building 8100, Cambridge Research Park,
Waterbeach, Cambridge, CB25 9TL, registered under company number 08921143 (together with its Affiliates referred to as “Horizon”). 

The Parties referred to above are individually also referred to as a “Party” and jointly as the “Parties”. 

Whereas: 
  

	(A)	 Celyad is a clinical-stage biopharmaceutical company that develops, owns or otherwise controls certain
intellectual property and know-how regarding the engineering of primary cells for therapeutic applications; 

  

	(B)	 Horizon is a translational genomics company that develops gene editing and modulation technologies and supplies
patient-relevant drug discovery tools and diagnostic reference materials; 

  

	(C)	 On 12 September 2017, the Parties have concluded an MNDA (as defined below); following the execution of
said MNDA, the Parties have discussed on certain business terms on which they could consider formalizing a license arrangement; 

  

	(D)	 The Parties are interested in conducting the Research Collaboration (as defined below), depending on the
outcome of which Celyad may be interested in obtaining an exclusive license from Horizon on the Horizon Intellectual Property Rights to use, research, develop, manufacture, and sell the Product in the Field in the Territory (as all such terms are
defined below) and Horizon may be willing to grant Celyad such exclusive license; 

  

	(E)	 The Parties have now agreed the terms of the Research Collaboration and of the license that may subsequently be
entered into. 

  
 Page 1 of 24 

 CONFIDENTIAL 
  

 It is agreed as follows: 

1. Definitions 
  

	1.1.	 Whenever used in this Agreement with an initial capital letter, the terms defined in this Clause 1
shall have the meanings specified below. 

 “Affiliate” means, with respect to a particular Party, a
person, corporation, partnership, or other entity that controls, is controlled by or is under common control with such Party. For the purposes of this definition, the word “control” (including, with correlative meaning, the terms
“controlled by” or “under the common control with”) means the actual power, either directly or indirectly through one or more intermediaries, to direct or cause the direction of the management and policies of such entity, whether
by the ownership of fifty per cent (50%) or more of the voting stock of such entity, or by contract or otherwise; 

“Agreement” means this license agreement as entered into between the Parties; 

“Applicable Laws” means all federal, state, local, national and supra-national laws, statutes, rules and regulations,
including any rules, regulations or orders of Regulatory Authorities, major national securities exchanges or major securities listing organizations, that may be in effect from time to time during the Term and applicable to a particular activity or
exercise of rights hereunder; 
 “Business Day” means a day, other than a Saturday or a Sunday or a public holiday, on which
banking institutions in Belgium and the United States of America are open for business; 
 “Business Hours” means 9:00 to
17:30 of each Business Day in the country of incorporation of the recipient; 
 “Celyad Background IP” means any
Intellectual Property Rights owned or controlled by Celyad or any of its Affiliates which (i) are in existence at the Effective Date or (ii) are developed by Celyad Representatives during the Term but independently of this Agreement and
independently of the Horizon Background IP; 
 “Celyad Foreground IP” means any Foreground IP other than the Horizon
Foreground IP; 
 “Code(s) of Conduct” has the meaning given to it in Clause 9.1; 

“Collaboration Term” means eighteen (18) months as from the Effective Date; 

“Confidential Information” means any and all information or material, whether oral, visual, in writing or in any other form,
that has been disclosed to the Recipient or any of its Affiliates by or on behalf of the Discloser or any of its Affiliates pursuant to this Agreement or in connection with the transactions and activities contemplated hereby or any discussions or
negotiations with respect thereto, including all data, documents, drawings, test reports, operating and testing procedures, manufacturing practices and Know-how, instruction manuals, materials, recipes and
formulae, tables of operating conditions, corporate organization, business plans, unpublished patent applications, marketing and sales reports, forecasts, pricing information, customer lists and the like and not as a whole readily available to the
public; 
 “Discloser” has the meaning given to it in Clause 17.2; 

  
 Page 2 of 24 

 CONFIDENTIAL 
  

 “Effective Date” means the date on which this Agreement is signed by both
Parties; 
 “Effective IND” means an IND that went into effect as described in 21 CFR 312.40(b); 

“Field” means the treatment of human diseases through Chimeric Antigen Receptor CAR-T-cell therapy in which cells are modified to knockdown Targets or Targets using shRNA; 

“First Commercial Sale” means, with respect to any Product, the first sale for end use or consumption of such Product in a
country after the Regulatory Authority of such country has granted Regulatory Approval. Sale to an Affiliate or Sublicensee will not constitute a First Commercial Sale, unless the Affiliate or Sublicensee is the end user of the Product; 

“Foreground IP” means any Intellectual Property Rights generated pursuant to this Agreement through the Research Collaboration
during the Term; 
 “Horizon Background IP” means the Horizon Patents, Horizon
Know-how and any other Intellectual Property Rights owned or controlled by Horizon or any of its Affiliates which (i) are in existence at the Effective Date; and/or (ii) developed by or on behalf of
Horizon independently of this Agreement; 
 “Horizon Foreground IP” means any Foreground IP generated solely by Horizon
Representatives during the course of, in furtherance of, and/or as a direct result of such Representatives performing an activity pursuant to this Agreement; 

“Horizon Intellectual Property Rights” means any Horizon Background IP and Horizon Foreground IP; 

“Horizon Know-how” means the internally documented
Know-how of Horizon relating to the Product, which is required and/or relevant to the activities that will be carried out by Celyad in the context of the license granted to it under this Agreement, including
the Know-how listed in Schedule 1; 
 “Horizon Patents” means the Patents listed in
Schedule 1; 
 “IND” means an Investigational New Drug Application filed with the FDA, or the equivalent application or
filing filed with any equivalent Regulatory Authority outside the United States of America (including any supra-national agency, such as in the European Union) necessary to commence human clinical trials in such jurisdiction; 

“Intellectual Property Rights” means any and all Patents and Know-how, as well any
other rights, title and interest held in (i) patents, utility models, designs (whether registered or unregistered), copyrights, trade marks, trade secrets, confidentiality and other proprietary rights including all rights to know-how and other technical information; (ii) the benefit of all registrations and applications to register any of the foregoing; and (iii) any and all other rights similar or analogous to any of the
foregoing whether arising or granted in any jurisdiction; 
 “Joint IP” has the meaning given to it in Clause 12.4; 

  
 Page 3 of 24 

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 “Know-how” means (a) any
scientific or technical information, results and data of any type whatsoever, in any tangible or intangible form whatsoever, that is not in the public domain or otherwise publicly known, including databases, practices, methods, techniques,
specifications, formulations, formulae, knowledge, know-how, skill, experience, test data, including pharmacological, medicinal chemistry, biological, chemical, biochemical, toxicological and clinical test
data, analytical and quality control data, stability data, studies and procedures, and manufacturing process and development information, results and data, and (b) any biological, chemical, or physical materials, and (c) any industrial
information that is not in the public domain or otherwise available to the public; all to the extent not claimed or disclosed in a Patent; 

“MAA” means an application for authorization to market the Product in any country or group of countries outside the United
States, as defined in Applicable Laws and filed with the Regulatory Authority of a given country or group of countries; 

“MNDA” means the Mutual Non-Disclosure Agreement executed on 12 September 2017
between the Parties; 
 “NDA” means a New Drug Application in the United States for authorization to market a Product, as
defined in Applicable Laws and filed with the FDA; 
 “Net Sales” means, with respect to any Product, the gross invoiced
sales of such Product by Celyad or its Affiliates, as applicable, to Third Parties after the First Commercial Sale of such Product, less the following deductions to the extent included in the gross invoiced sales price for such Product or otherwise
directly paid or incurred by Celyad or its Affiliates, as applicable, with respect to the sale of such Product: 
  

	 	(i)	 normal and customary trade and quantity discounts, credits and allowances actually allowed and properly taken
directly with respect to sales of such Product; 

  

	 	(ii)	 amounts repaid or credited by reason of rejections, recalls, returns, rebates, government mandated rebates and
allowances; 

  

	 	(iii)	 chargebacks and other amounts paid on sale or dispensing of such Product; 

 

	 	(iv)	 retroactive price reductions that are actually allowed or granted; 

 

	 	(v)	 tariffs, duties, excise, sales, value-added or other taxes (other than taxes based on income);

  

	 	(vi)	 cash discounts for timely payment; 

 

	 	(vii)	 delayed ship order credits; 

 

	 	(viii)	 discounts pursuant to patient discount programs; and 

 

	 	(ix)	 freight, shipping and insurance charges. 

In no event will Products provided at cost for clinical trials or provided for charitable purposes or for free sampling be included in Net
Sales. 
 “Option” has the meaning given to it in Clause 3; 

“Patents” means (a) all patents, patent applications, utility models and design patents in any country or supranational
jurisdiction, and (b) any provisionals, substitutions, divisions, continuations, continuations in part, reissues, renewals, registrations, confirmations, re-examinations, extensions, supplementary
protection certificates and the like, of any such patents or patent applications; 

  
 Page 4 of 24 

 CONFIDENTIAL 
  

 “Phase 2 Clinical Trial” means a clinical study of an investigational
product in human patients with the primary objective of characterizing its activity in a specific disease state as well as generating more detailed safety, tolerability, and pharmacokinetics information as described in 21 CFR 312.21(b), or a
comparable clinical study prescribed by the relevant Regulatory Authority in a country other than the United States including a human clinical trial that is also designed to satisfy the requirements of 21 CFR 312.21(a) or corresponding foreign
regulations and is subsequently optimized or expanded to satisfy the requirements of 21 CFR 312.21(b) (or corresponding foreign regulations) or otherwise to enable a Phase 3 Clinical Trial; 

“Phase 3 Clinical Trial” means a clinical study of an investigational product in human patients that incorporates accepted
endpoints for confirmation of statistical significance of efficacy and safety with the aim to obtain Regulatory Approval in any country as described in 21 CFR 312.21(c), or a comparable clinical study prescribed by the relevant Regulatory Authority
in a country other than the United States; 
 “Product(s)” means any Chimeric Antigen Receptor T-cell therapy in which cells are modified to knockdown Targets or Targets the use of shRNA using Horizon Intellectual Property Rights pursuant to this Agreement, or any other product whose manufacture, use or sale
would, in the absence of a license from Horizon, constitute direct, indirect, contributory or any other type of infringement of (one or more claims of) Horizon Intellectual Property Rights; 

“Quarter” shall have the meaning given to it in Clause 8.2; 

“Recipient” has the meaning given to it in Clause 17.2; 

“Regulatory Approval” means any and all approvals, licenses (including product and establishment licenses), permits,
certifications, registrations, or authorizations of any Regulatory Authority necessary to use, research, develop, manufacture and sell the Product for use in the Field in the Territory, including all INDs, MAAs and the manufacturing license and
marketing registration required under the Applicable Laws of such applicable country in the Territory, or any update thereto, as well as pre- and post-approval marketing studies, labelling approvals,
technical, medical and scientific licenses; 
 “Regulatory Authority” means any national, supra-national, regional, federal,
state, provincial or local regulatory agency, department, bureau, commission, council or other governmental entity (including, without limitation, the EMA, the FDA, the PMDA and any governmental unit having jurisdiction over the use, research,
development, manufacture and sale of the Product in the Field in the Territory); 
 “Representative(s)” shall mean, in
relation to a Party, its respective Affiliates and their officers, employees, consultants, agents, and subcontractors; 
 “Research
Collaboration” means the collaboration between the Parties for joint research and/or development in the Field in accordance with this Agreement and with the Research Plan and which has the objective to identify and optimize shRNA to
knockdown the Target, and to demonstrate efficacy in the Field; 
 “Research Plan” means the research plan to be agreed
between the Parties, to be attached hereto as Schedule 2 and to include an itemized description of research and development activities, roles and responsibilities of the Parties, costs and estimated timelines for the Research Collaboration; 

  
 Page 5 of 24 

 CONFIDENTIAL 
  

 “Royalty Agreement” has the meaning given to it in Clause 7.4; 

“Sublicensee” has the meaning given to it in Clause 7.4; 

“Target” means any of the following genes or any combination thereof: MICA, MICB, ULBP1, ULBP2, ULPBP3, ULPBP4, ULPBP5 or
ULPBP6, and these are not limited to human genes and includes homologous genes in any species; 
 “Tax” or
“Taxation” means any form of tax or taxation, levy, duty, charge, social security charge, contribution or withholding of whatever nature (including any related fine, penalty, surcharge or interest) imposed by, or payable to, any
government, state or municipality, or any local, state, federal or other fiscal, revenue, customs, or excise authority, body or official anywhere in the world; 

“Tax Authority” means any government, state or municipality, or any local, state, federal or other fiscal, revenue, customs,
or excise authority, body or official anywhere in the world, authorized to levy Tax; 
 “Term” has the meaning given to it
in Clause 21.1; 
 “Territory” means the entire world; 

“Third Party” means any person other than Horizon, Celyad or their respective Affiliates; 

“Threatened Claim” means a cease and desist letter or a letter or other written communication sent by a Third Party,
explicitly and/or inherently (i) alleging that the conduct of development, commercialization or manufacturing activities of the Product in the Territory infringes, misappropriates, violates or makes unauthorized use of such Third Party’s
Intellectual Property Rights; or (ii) questioning the Party’s assumed right to the alleged use of such Third Party’s Intellectual Property Rights; or (iii) including any written claim offering a license to the Party or that the
Party must license or refrain from using such Third Party’s Intellectual Property Rights; 
 “Valid Claim” means a
patent claim of an issued patent that has not expired or been revoked, held invalid or unenforceable by a patent office, court or other governmental agency of competent jurisdiction in a final and
non-appealable judgment (or judgment from which no appeal was taken within the allowable time period); 

“VAT” means, within the EU, such Tax as may be levied in accordance with (but subject to derogations from) Directive
2006/112/EC and, outside the EU, value added tax or any form of indirect tax levied by a relevant Tax Authority, as well as all other forms of indirect taxes levied by the relevant Tax Authority on the purchase of a good or a service, including
sales tax and good and service tax; 
 “Year” means each twelve (12) month period commencing on 1 January and
ending on the 31 December throughout the Term of this Agreement except that the first Year shall commence on the Effective Date and end on 31 December and the last Year shall commence on 1 January and end on the date of termination of
this Agreement. 

  
 Page 6 of 24 

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	1.2.	 Construction rules 

The language of this Agreement shall be deemed to be English and no rule of strict construction shall be applied against any Party. 

 

	1.3.	 Modification and re-enactment of statutes 

References to a statutory provision include that provision as from time to time modified or re-enacted.

  

	1.4.	 Information 

References to books, records or other information mean books, records or other information in any form including paper, electronically stored
data, magnetic media, film and microfilm. 
  

	1.5.	 Non-limiting effect of words 

The words “including” and “include” and words of similar effect shall not be deemed to limit the general effect of the
words which precede them. 
  

	1.6.	 References 

Any reference to this Agreement include its schedules and references to recitals, clauses, sub-clauses
and schedules are to recitals, clauses, sub-clauses and schedules to this Agreement. Any reference to a statutory provision includes that provision as from time to time modified or re-enacted. 
  

	2.	 Research Collaboration 

 

	2.1.	 The Parties agree to undertake the Research Collaboration for the Collaboration Term in accordance with
the terms and conditions of this Agreement and as described in the Research Plan. 

  

	2.2.	 Representatives of Celyad and Horizon, such representatives to be nominated by each party within two
weeks of execution of this Agreement, shall meet at such intervals and at such places as the Parties shall agree for the purpose of setting up the Research Plan and of regularly reviewing the Research Collaboration and all matters relating to the
conduct of the Research Collaboration. 

  

	2.3.	 Celyad shall bear all costs related to the Research Collaboration, including costs reasonably incurred
by Horizon as from the Effective Date and as specified in the Research Plan. 

  

	3.	 Option to License 

 

	3.1.	 During the Collaboration Term, Horizon grants Celyad an exclusive option to license Horizon Intellectual
Property Rights for use in the Field and in the Territory (“Option”). 

  
 Page 7 of 24 

 CONFIDENTIAL 
  

	3.2.	 In consideration of the Option, Celyad shall pay to Horizon an amount of twenty thousand US dollars (USD
20,000) within forty-five (45) days following the date of receipt of a validly issued and undisputed invoice. 

  

	3.3.	 If Celyad decides not to exercise the Option by the end of the Collaboration Term, this Agreement will
terminate and no further payment shall be due by Celyad to Horizon. 

  

	4.	 License Grant to Celyad 

 

	4.1.	 If Celyad exercises the Option within the Collaboration Term and subject to the terms and conditions of
this Agreement, Horizon shall grant to Celyad, and Celyad shall accept, an exclusive, royalty-bearing, sublicensable license to Horizon Intellectual Property Rights to research, to have researched, to develop, to have developed, to manufacture, to
have manufactured, to sell and to have sold (and generally to use and to have used) Products within the Field in the Territory during the Term. 

  

	4.2.	 Horizon shall not, during the Term and within the Field (i) itself exercise; or (ii) grant any
license to any Third Party to exercise, the rights granted to Celyad under Clause 4.1. 

  

	4.3.	 Celyad shall have the right to sublicense the rights granted to Celyad under Clause 4.1 to Third
Parties. 

  

	4.4.	 For the avoidance of doubt, Horizon shall retain all rights to exploit the Horizon Foreground IP how it
sees fit outside the Field. 

  

	5.	 License Grant to Horizon 

Subject to the terms and conditions of this Agreement, Celyad hereby grants to Horizon, and Horizon hereby accepts a non-exclusive, royalty-free, worldwide, sub-licensable license to any and all Celyad Foreground IP for use in the Field solely for the purpose of fulfilling Horizon’s
obligations under this Agreement. 
  

	6.	 Assignment by Horizon 

Horizon may assign all or any part of Horizon Intellectual Property Rights licensed hereunder, provided that any assignment by Horizon of all
or part of said Horizon Intellectual Property Rights shall be subject to this Agreement which shall be brought to the attention of the assignee and subject to the assignee committing to maintain the license under this Agreement. 

 

	7.	 Financial Terms 

 

	7.1.	 In consideration for the license rights granted to Celyad under this Agreement, Celyad shall make the
following one-time payments to Horizon upon the achievement by Celyad of the below Product development milestones and within forty-five (45) days upon receipt of a validly issued and undisputed invoice.

  
 Page 8 of 24 

 CONFIDENTIAL 
  

					
	 First Product milestone
	  	Payment in USD	 
	Celyad’s exercise of the Option.	  	 	[***]	 
	 The first Effective IND, filed by Celyad, relating to the first Product.
	  	 	[***]	 
	 The filing by Celyad for the first Phase 2 Clinical Trial relating to the first Product.
	  	 	[***]	 
	 The filing by Celyad for the first Phase 3 Clinical Trial relating to the first Product.
	  	 	[***]	 
	 The filing by Celyad of the first MAA or NDA relating to the first Product.
	  	 	[***]	 
	 The first MAA or NDA approval by the relevant Regulatory Authority for the first Product.
	  	 	[***]	 

  

	7.2.	 In consideration for the license rights granted to Celyad under this Agreement, Celyad shall pay to
Horizon a royalty fee of [***] per cent ([***]%) on Net Sales of the Product in the Territory, on a country by country basis, for each country until the date upon which the last Valid Claim covering the Product expires in such country. If the
Product is not covered by a Valid Claim that would be infringed by the use or sale of the Product in a given country, then Celyad shall not pay any royalties on Net Sales of the Product in such country. 

 

	7.3.	 If Celyad is required to obtain a license under one or more Patents of any Third Party that, in the
absence of such license, would be infringed by the use or sale of the Product, then 50% (fifty per cent) of the royalties actually paid under such Third Party license by Celyad for use or sale of such Product in a country will be creditable against
the royalty payments due to Horizon by Celyad with respect to the use or sale of such Product in such country under Clause 7.2. In no event shall the aggregate royalty reductions provided for in this Clause, in any Year, exceed 50% (fifty per
cent) of the royalty amount otherwise due to Horizon under Article. For the avoidance of doubt, the only royalties paid to Third Parties creditable against the royalty payments due to Horizon under this Agreement are those paid under licenses to
Patents of Third Party related to shRNA technologies. 

  

	7.4.	 In case Celyad sublicenses all or part of its rights under this Agreement to a Third Party
(“Sublicensee”), then the Sublicensee and Horizon shall establish in writing a royalty agreement (“Royalty Agreement”) which shall provide that Sublicensee shall pay royalties directly to Horizon at the rate of
[***] per cent ([***]%) on Sublicensees’ net sales of the Product in the Territory. Such Royalty Agreement shall be in writing and all its terms, including definitions, shall be substantially similar to the terms of this Agreement. Horizon
cannot refuse to conclude and sign such agreement except for ethical reasons related to the Sublicensee business conduct. 

  

	7.5.	 Unless otherwise stated, any consideration payable under this Agreement shall be exclusive of VAT.

  

	8.	 Accounting and Payment 

 

	8.1.	 Milestone Payment Reports. Celyad shall report each event that triggers a payment to Horizon pursuant to
Clause 7.1 in writing and within ten (10) Business Days upon such event to Horizon. Horizon shall issue an invoice for such payment. 

  
 Page 9 of 24 

 CONFIDENTIAL 
  

	8.2.	 Royalty Payment Reports. As from the first Year which includes the First Commercial Sale of the first
Product, and for each Year thereafter, Celyad shall, within forty-five (45) days after the end of each Quarter for an applicable Year, deliver to Horizon a report which sets out in reasonable detail the
information that is necessary for Horizon to calculate any royalty fee due to Horizon under Clause 7.2. Horizon shall issue an invoice for such payment. For clarity and the purposes of this Agreement, a “Quarter” shall mean (for each
Year) each of the periods beginning on and including: (i) January 1st and ending on and including March 31st; and (ii) April 1st and ending on and including June 30th; (iii) July 1st and ending on and including
September 30th; and October 1st and ending on and including December 31st.

  

	8.3.	 Celyad shall keep records of account sufficient to enable accurate calculations of any amounts due under
this Agreement to Horizon. 

  

	8.4.	 Celyad shall make each payment due to Horizon within forty-five (45) days upon receipt of a validly
issued and undisputed invoice. 

  

	8.5.	 If there is a dispute as to the amounts to be paid, the Parties shall select an independent accountant
to be agreed between them to audit the records of Celyad, on reasonable notice and during regular business hours, and to verify Celyad’s statements and payments due under this Agreement. In case of such audit, Celyad shall make available all
relevant records (either in hard or soft copy) at any (physical or virtual) place at or close to Celyad’s usual place of business. If the audit reveals that any statement or payment has not been rendered or made in accordance with this
Agreement, or that any statement rendered or payment made by Celyad was inaccurate by more than five per cent (5%), then Celyad shall pay the cost of the inspection without any prejudice to any other remedies or claims of Horizon under the Agreement
or Applicable Laws. The independent accountant shall not be authorized to disclose to Horizon any information other than information relating to any amounts owed by Celyad under this Agreement. Horizon shall maintain in confidence and shall oblige
the independent accountant to maintain in confidence all information received under this Clause. The decision of the independent accountant as to the amounts to be paid under the Agreement shall, in the absence of manifest error, be final and
binding upon the Parties. 

  

	8.6.	 Any amounts due under this Agreement shall be paid by Celyad by wire transfer in US dollars to the
following Horizon’s bank account: Beneficiary: Horizon Discovery Limited; Bank: National Westminster Bank; Iban: GB10 NWBK 6073 0192 5156 14; Swift: NWBKGB2L or any other bank account notified to Celyad in accordance with Clause 22.

  

	8.7.	 The amounts set out in Clause 7.1 shall not be altered regardless of the number of Patents or Know-how covering the Product. 

  

	9.	 Compliance 

  

	9.1.	 Each Party shall take such steps as are necessary, including implementing and maintaining (at a minimum)
a robust internal compliance program, so as to ensure that its business it shall perform under this Agreement is carried out in accordance with all Applicable Laws and applicable codes of conduct and any reasonable ethical and compliance principles,
including the standards and principles as set out in Celyad’s and Horizon’s codes of conduct to be shared between the Parties upon request (hereinafter the “Codes of Conduct” and each a “Code of Conduct”).

  
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	9.2.	 Without limiting the generality of Clause 9.1, in performing this Agreement, each Party (i) shall
not offer to make, make, promise, authorize or accept any payment or giving anything of value, including bribes, either directly or indirectly to any public official, Regulatory Authority or anyone else for the purpose of influencing, inducing or
rewarding any act, omission or decision in order to secure an improper advantage, or obtain or retain business; and (ii) shall comply with all applicable anti-corruption and anti-bribery laws and regulations, including the Bribery Act 2010, the
U.S. Foreign Corrupt Practices Act and any other applicable anti-corruption law, such as the UN Convention Against Corruption and the OECD Convention. Each Party, its employees and agents shall not make any payment or provide any gift to a Third
Party in connection with such Party’s performance under this Agreement, except as may be expressly permitted in this Agreement, without first identifying the intended Third Party recipient to the other Party and obtaining the other Party’s
prior written approval. 

  

	9.3.	 Each Party shall require its employees and its subcontractors (if any) who will perform any activity
related to the Agreement to participate in an anti-corruption training and/or a training on such Party’s Code of Conduct and/or any related applicable company policy. 

 

	9.4.	 Each Party shall promptly comply with any request from the other Party for information and assistance to
enable such other Party to ensure audit and confirm compliance with Applicable Laws, regulations and standards. Each Party shall immediately notify the other Party upon becoming aware of any governmental or regulatory review, audit or inspection of
items related to the other Party or any other activities in connection with this Agreement. 

  

	9.5.	 Each Party shall ensure that it has kept and will keep complete and accurate records of all transactions
and expenses related to their business related to the Product in accordance with any and all Applicable Laws and standards. Each Party shall have the right to ask for specific details of the other Party’s compliance program and each Party shall
further have the right to conduct an audit of the other Party’s compliance program. The audited Party shall assist the other Party in any such audit that the other Party may wish to perform at the auditing Party’s expense, provided that
the auditing Party has given reasonable notice, and in no event less than three (3) months. Notwithstanding the foregoing, each Party assumes no duty or obligation to audit or review the other Party’s compliance with this Clause 9.

  

	10.	 Regulatory Matters 

 

	10.1.	 The Parties shall perform their respective obligations under this Agreement in accordance with current
quality standards and all Applicable Laws. 

  

	10.2.	 Horizon shall reasonably support Celyad by providing relevant scientific, clinical and technical
information, knowledge or data known to it and in its possession to support submission of any application for Regulatory Approvals (and maintenance of such Regulatory Approvals) of the Product by Celyad at Celyad’s cost. 

 

	11.	 Technical Assistance 

 

	11.1.	 Horizon will reasonably support the appropriate transfer of information and technology to Celyad as is
required to enable Celyad to benefit from and exercise the rights granted to Celyad under this Agreement. This shall include providing copies of all relevant documents, training and knowledge in its possession, to the extent material to render such
transfer effective. 

  
 Page 11 of 24 

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	12.	 Foreground IP 

 

	12.1.	 Horizon and Celyad shall each promptly disclose to the other the Horizon Foreground IP and the Celyad
Foreground IP respectively. 

  

	12.2.	 Celyad Foreground IP shall be owned by Celyad. Celyad will be solely responsible and use commercially
reasonable efforts to file for, prosecute, maintain, keep in force and defend Celyad Foreground IP, at its expense. If Celyad decides not to file for a specific Patent (application), or if Celyad decides to abandon or to not further defend an
Intellectual Property Right as part of Celyad Foreground IP, it will notify Horizon at least thirty (30) days in advance, and Horizon can decide at its own discretion whether or not to file for a Patent (application) or take over such
Intellectual Property Rights or responsibility and all associated costs and Celyad will still have a royalty-free license under such assigned rights for the duration of such rights. 

 

	12.3.	 Horizon Foreground IP shall be owned by Horizon. Horizon will be solely responsible and use commercially
reasonable efforts to file for, prosecute, maintain, keep in force and defend Horizon Foreground IP, at its expense. If Horizon decides not to file for a specific Patent (application), or if Horizon decides to abandon or to not further defend an
Intellectual Property Right as part of Horizon Foreground IP, it will notify Celyad at least thirty (30) days in advance, and Celyad can decide at its own discretion whether or not to file for a Patent (application) or take over such
Intellectual Property Rights or responsibility and all associated costs and Horizon will still have a royalty-free license under such assigned rights for the duration of such rights. 

 

	12.4.	 For clarity and for the purposes of this Agreement, in respect of ownership of Foreground IP that is
jointly developed by Horizon Representatives and Celyad Representatives (“Joint IP”), the Parties agree as follows: 

  

	 	(i)	 Joint IP in the Field shall be owned by Celyad; and 

 

	 	(ii)	 Joint IP outside of the Field shall be owned by Horizon. 

 

	13.	 Maintenance of Intellectual Property Rights 

 

	13.1.	 Horizon shall during the Term of this Agreement: 

 

	 	13.1.1.	 use commercially reasonable efforts to file for, maintain, register (where applicable), prosecute and
keep in force and defend Horizon Patents and Horizon Know-how, at its expense; 

  

	 	13.1.2.	 use commercially reasonable efforts to continue at its expense the filing, prosecution, registration or
maintenance of the applications for Horizon Patents, unless Celyad gives its consent to abandoning one or more of them or unless Horizon hands over to Celyad the above responsibility. If Horizon decides to abandon or to not further defend (e.g. in
oppositions/appeal proceedings) a Horizon Patent, it will notify Celyad thirty (30) days in advance, and Celyad shall decide at its own discretion whether or not to take over such responsibility and all associated costs. In this case, Horizon
will still have a royalty-free license under such assigned rights for the duration of such rights. 

  
 Page 12 of 24 

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	14.	 Infringement 

  

	14.1.	 Either Party, as the case may be, shall upon becoming aware of a suspected infringement of any of the
Foreground IP and Horizon Patents or any unauthorized use or threatened use of Foreground IP and Horizon Know-how, promptly notify the other Party and provide available particulars thereof.

  

	14.2.	 If such infringement or use consists of any act which (if done by Celyad) would be within the scope of
the license granted by Clause 4.1, Horizon shall, subject to clause 15.2, decide whether to take such action (whether litigation, arbitration or compromise as appropriate) as is necessary for the protection of Horizon Intellectual Property Rights.
If Horizon notifies Celyad that it does not intend to take such action, or, within fifteen (15) Business Days of either Party becoming aware of such infringement, fails to take such action, Celyad may commence proceedings. Neither Party shall
settle any proceeding under this Clause without the prior written consent of the other Party, which consent shall not be unreasonably withheld. Any recovery received as a result of any action pursuant to this Clause 14.2 shall be used first to
reimburse the enforcing Party for the costs and expenses (including court, attorneys’ and professional fees) incurred in connection with such action. The remainder of the recovery attributable to the action shall be paid to Celyad in such a
percentage as it is appropriate should Celyad be injured by such action in relation to the Products. 

  

	14.3.	 Either Party will give the other Party all such reasonable assistance as the Party in charge of
proceedings for suspected infringements under Clause 14.2 may reasonably require, at such assisting Party’s own cost. 

  

	14.4.	 Neither Party will incur liability to the other as a consequence of such proceeding or any unfavorable
decision resulting therefrom, but this sentence is without limitation of a Party’s other obligations under this Agreement. 

  

	15.	 Third Party Infringement 

 

	15.1.	 Each Party shall notify the other Party of any risk identified relating to the potential infringement of
a Third Party Intellectual Property Right by the exercise of the license rights granted under this Agreement, in due time upon its identification. 

  

	15.2.	 After notifying any such risk derived from a relevant Third Party Intellectual Property Right to the
other Party, the Parties shall discuss and, as the case may be, agree on the appropriate mitigation or remedy strategy. 

  

	15.3.	 Each Party or its permitted subcontractors shall promptly notify the other Party in writing if it
receives a claim or a Threatened Claim by a Third Party for infringement or for inducing or contributing to infringement of Intellectual Property Rights controlled by a Third Party, which would be directly related to the use, research, development,
manufacturing and/or sale of the Product. 

  

	15.4.	 Upon receipt of a claim, the Parties shall discuss in good faith, consult and determine an appropriate
strategy for course of action or for defense against any such claim. Each Party shall render the other Party all reasonable assistance in defending any such claim. 

  
 Page 13 of 24 

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	15.5.	 In the case of a filed or Threatened Claim by a Third Party for infringement or for inducing or
contributing to infringement in the Territory of any Third Party Intellectual Property Rights, and in case of an infringement risk as identified and discussed by the Parties according to 15.1 and 15.2, and provided that an infringement opinion by an
external qualified counsel as determined by the Parties comes to the conclusion that the chances of a court of law confirming a finding of infringement is more than fifty per cent (50%), Celyad will have the right to immediately delay or suspend the
use, research, development, manufacturing and/or sale of the Product. At the same time Horizon shall, at its own expense, investigate the below options within the specified terms: 

 

	 	15.5.1.	 use commercially reasonable efforts to have started and progressed on negotiating for the benefit of
Celyad (and any sub-licensees in multiple tiers) the right to continue using such Product within six (6) months; or 

 

	 	15.5.2.	 use commercially reasonable efforts to have initiated development activities in order to replace such
Product with a non-infringing product which performs substantially the same functions as the Product within six (6) months; or 

 

	 	15.5.3.	 use commercially reasonable efforts to have initiated development activities in order to modify such
Product to become non-infringing, provided always that it performs substantially the same functions as the Product, within six (6) months. 

The Parties shall after this term agree on a maximum period for investigating the above options during which period the use, research,
development, manufacturing and/or sale of the Product by Celyad are suspended, in view of any commercial and regulatory requirements and considerations. 
  

	15.6.	 Celyad shall assist and cooperate with Horizon, at its costs, in any such defense or action taken by
Horizon in relation to claims of any Third Party relating to the Product in the Field. 

  

	16.	 Insurance 

Each Party, at its own expense, shall maintain during the Term liability insurance in an amount consistent with industry standards, but in no
event in an amount less than USD one million (USD 1,000,000.00) per occurrence and USD five million (USD 5,000,000.00) in aggregate. 
  

	17.	 Confidentiality 

 

	17.1.	 Upon execution of this Agreement, the MDNA shall cease to exist and be in full force and effect in its
entirety and any obligation of confidentiality thereunder shall be absorbed by this Agreement. 

  

	17.2.	 For the purposes of this Agreement, “Recipient” shall mean a Party or a Party’s
Representative receiving Confidential Information under this Agreement from the “Discloser” which shall mean the Party disclosing Confidential Information to Recipient. 

 

	17.3.	 During the Term and for as long as this Clause 17 shall survive in accordance with Clause 17.6, each of
the Parties shall take all steps necessary to preserve the secrecy of the Know-how and the Confidential Information for the sole purpose of their activities, using their rights and fulfilling their obligations
under this Agreement. Each Recipient is made aware of the confidentiality of the Confidential Information, as well as have in place express non-use and non-disclosure
provisions at least as protective as the provisions of this Agreement, prior to receiving the Confidential Information. 

  
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	17.4.	 Any Confidential Information disclosed to Recipient pursuant to this Agreement shall be handled in
confidence and shall not be used or disclosed to any Third Party (except Representatives) by the Recipient without the prior written consent of the Discloser. 

 

	17.5.	 The provisions of this Clause 17 shall not apply to Confidential Information which the Recipient can
demonstrate that: 

  

	 	17.5.1.	 is or later becomes freely available to the public otherwise than through the fault of the Recipient in
breach of this Agreement; 

  

	 	17.5.2.	 was in the possession of the Recipient prior to its receipt from the Discloser; 

 

	 	17.5.3.	 was independently received from a Third Party who is free from any obligations to Discloser not to
disclose it; 

  

	 	17.5.4.	 was conceived by the Recipient independently of the information received or acquired from the Discloser;
or 

  

	 	17.5.5.	 was required to be disclosed by law, government agency, court order, stock exchange authority or valid
discovery request in connection with a legal proceeding (“Statutory Disclosure”), provided that the Recipient provides the Discloser as promptly as possible with prior written notice of any such Statutory Disclosure (unless such
notice is impracticable or prohibited by such Applicable Laws) so that application for an appropriate protective order can be made by Discloser. The Recipient will fully cooperate (at the Discloser’s expense) in connection with the
Discloser’s efforts to obtain any such order or other remedy. The Recipient shall disclose only that portion of the Confidential Information that it is legally required to satisfy the Statutory Disclosure and such disclosure under this Clause
17.5.5 shall be made without liability from Recipient. 

  

	17.6.	 This Clause 17 shall survive termination of this Agreement for 10 (ten) years. 

 

	18.	 Press Releases and Publications 

 

	18.1.	 No Party shall issue any press release or make any other type of public disclosure relating or referring
to this Agreement without the prior written consent of the other Party. 

  

	18.2.	 No Party shall publish any articles or papers or make any presentations or any other type of public
disclosure relating or referring to Research Collaboration or the Foreground IP without the prior written consent of the other party. 

  

	19.	 Representations and Warranties 

 

	19.1.	 Horizon represents and warrants that, as of the Effective Date: 

  
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	 	19.1.1.	 it has all rights and/or interests in the Horizon Intellectual Property Rights necessary to grant the
licenses to Celyad under this Agreement; 

  

	 	19.1.2.	 to the best of its knowledge, it has not received any Threatened Claim in relation to the Horizon
Intellectual Property Rights; 

  

	 	19.1.3.	 the Horizon Intellectual Property Rights can be applied for the purposes of research, development,
manufacturing and sale of the Product by Celyad or by a Third Party on behalf of Celyad and that, to the best of its knowledge and for the purposes of this Agreement, the Horizon Intellectual Property Rights do not infringe any Third Party’s
Intellectual Property Rights, except the Third Party’s Intellectual Property Rights referred to in Schedule 3, or do not misappropriate any Third Party’s Know-how; 

 

	 	19.1.4.	 to the best of its knowledge, the list of Horizon Know-how and
Horizon Patents in Schedule 1 is accurate. 

  

	19.2.	 For the avoidance of doubt, the warranties provided under this Clause 19 are not intended to warrant the
fitness for any specific use including any specific use or application of the Product. 

  

	20.	 Indemnities 

  

	20.1.	 Horizon hereby agrees to defend, indemnify and hold Celyad and its Representatives harmless from and
against any and all losses, damages, costs (including reasonable court costs and fees of attorneys and other professionals), penalties, liabilities (including strict liabilities), fines, amounts and expenses in execution of a final/non appealable
judgment or a settlement (individually and collectively, “Loss(es)”) to be paid by Celyad, to the extent such Celyad Losses are as a result of a claim or suit started from a Third Party for: 

 

	 	20.1.1.	 bodily injury, personal injury, death and property damage caused by any negligence or willful misconduct
or wrongdoing that can be attributable to Horizon or its Representatives under the Applicable Laws as applicable to this Agreement; 

  

	 	20.1.2.	 a breach by Horizon or its Affiliates of its obligations, representations and warranties under this
Agreement; and 

  

	 	20.1.3.	 the negligence or willful act or omission of Horizon or any person for whose actions or omissions
Horizon is liable under Applicable Laws or under this Agreement; 

 provided, however, that in all cases referred to above,
Horizon’s obligation under this Clause 20.1 shall be proportionally reduced or completely removed to the extent that Celyad Loss was partially or fully caused by: 
  

	 	20.1.4.	 the negligence or willful misconduct of Celyad or any person for whose actions or omissions Horizon is
liable under the Applicable Laws or under this Agreement; or 

  

	 	20.1.5.	 any breach by Celyad of its representations, warranties and/or obligations assumed hereunder; or

  

	 	20.1.6.	 any bodily injury, personal injury, death and property damage caused by the negligence or willful
misconduct or wrongdoing of Celyad or its Representatives and Celyad shall accordingly indemnify Horizon for any and all Losses that Horizon would incur under this Clause 20.1.6. 

  
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	20.2.	 Horizon shall indemnify Celyad against all liability, loss, damages, costs or other expenses incurred or
suffered by Celyad as a result of the use by Horizon (or on its behalf or authority) of the Intellectual Property Rights held by Celyad without Celyad’s consent, or for any purpose other than as set out in this Agreement. 

 

	20.3.	 Neither Party shall have any liability to the other Party, its Affiliates or their respective entitled
persons for any indirect, consequential, punitive or incidental damages, including for loss of profits, revenue or income, loss of business opportunity, arising out of or relating to this Agreement. 

 

	20.4.	 To the extent permitted by law, except in connection with an indemnification obligation hereunder and
except with respect to the breach of any of obligations set forth in Clauses 15, 17 and 19, neither Party shall be liable to the other under this Agreement for special, incidental, indirect, punitive, or consequential damages, for loss of profit,
loss of business, or depletion of goodwill (howsoever caused, whether under breach of contract or warranty, tort including negligence, strict liability or otherwise) which arise out of or in connection with this Agreement. 

 

	20.5.	 To the extent permitted by law, except in connection with an indemnification obligation hereunder and
except with respect to the breach of any of obligations set forth in Clauses 15, 17 and 19, Horizon’s entire liability in contract, tort (including negligence or breach of statutory duty), misrepresentation or otherwise, arising out of or in
connection with this Agreement shall, be limited to the US Dollar value of this license at the time such breaches occurred. 

  

	21.	 Term and termination 

 

	21.1.	 The Agreement shall enter into force on the Effective Date and, unless earlier terminated as provided in
this Agreement, shall expire, at the earliest of either (i) the tenth (10th) anniversary of the date of First Commercial Sale of the Product in the Territory, or (ii) upon the last Valid Claim covering the Product or its use or sale
(including supplementary protection certificates) to expire in a country in the Territory (“Term”). 

  

	21.2.	 Termination by either Party 

 

	 	21.2.1.	 Termination for Insolvency. Either Party may terminate this Agreement before its expiration with
immediate effect, by written thirty (30) days’ notice, to the other Party if: 

  

	 	(i)	 a receiver or administrative receiver is appointed over the whole or any part of the other Party’s assets
or an order is made by a court of competent jurisdiction, a petition is filed, a notice is given or a resolution is passed for the winding-up or administration of the other Party, or any step is taken by any
person with a view to bringing about any of the preceding events; or 

  

	 	(ii)	 the other Party commences negotiations with any of its creditors with a view to rescheduling any of its debts
or enters into any compromise or arrangement with its creditors (in each case other than as part of a voluntary scheme for the reconstruction or amalgamation of the other Party as a solvent corporation and the resulting corporation, if a different
legal entity, undertakes with Horizon or Celyad as applicable to be bound by the terms of this Agreement); or 

  
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	 	(iii)	 the other Party is capable of being deemed unable to pay its debts. 

 

	 	21.2.2.	 Termination for Material Breach. Without prejudice to any remedy or claim it may have against the other
Party for material breach or non-performance of this Agreement, each Party shall have the right to terminate this Agreement with immediate effect in the event that the other Party fails to materially comply
with or perform any material provision of this Agreement and, in case of a curable material breach, in the further event that such other Party, after having been given written notice, should fail to discontinue and to remedy such violation within a
remedy period of sixty (60) days after receipt of such notice. 

  

	 	21.2.3.	 Termination for Force Majeure. Either Party may terminate this Agreement in accordance with the terms of
Clause 30.2. 

  

	21.3.	 Termination by Celyad 

Celyad may terminate this Agreement before its expiration, including in the event that Celyad decides not to exercise the Option prior to the
end of the Collaboration Term, at any time without cause and without any compensation to Horizon (except for reasonable and documented costs incurred by Horizon as a result of the Research Collaboration during the Collaboration Term prior to
termination) by providing Horizon thirty (30) days written notice. 
  

	21.4.	 Effects of termination 

 

	 	21.4.1.	 Celyad shall have the right, for six (6) months from the date of termination of this Agreement, to
sell stocks of the Products manufactured by Celyad itself or supplied by Horizon prior to the date of termination. 

  

	 	21.4.2.	 Any amounts due under this Agreement shall be paid to Horizon within thirty (30) days after the
date of effective expiration or termination of this Agreement and Celyad shall at the same time pay any amounts due under this Agreement and render statements in respect of all other Products sold, put into use or otherwise disposed of prior to the
date of effective expiration or termination. 

  

	 	21.4.3.	 The provisions relating to the payment of any amounts due under this Agreement and the rendering and
auditing of accounts and other information, shall remain in force as long as may be necessary in order to wind-up the outstanding obligations of both Parties. 

 

	 	21.4.4.	 As from termination of this Agreement, Horizon shall cease using the Celyad Foreground IP. Horizon shall
deliver to Celyad all documents embodying the Celyad Foreground IP in its possession or control, or destroy (and certify such destruction to Celyad) such documents, it being understood that Horizon may retain one (1) copy of any such document
exclusively for record-retention purposes and for the purpose of monitoring compliance with its obligations pursuant to this Agreement and subject to any copies remaining on Horizon`s standard computer back-up
devices (which copies Horizon agrees not to access after the termination). 

  
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	 	21.4.5.	 The provisions of Clause 17 (Confidentiality), Clause 20 (Indemnities), as well as any other provision
which by its terms or by the context thereof, is intended to survive termination, shall in any event remain in force for a period of ten (10) years. 

  

	22.	 Notices 

  

	22.1.	 Any notice given under this Agreement shall be in writing and may be delivered by hand to the relevant
Party or sent by recorded delivery or emailed to the address or email address stated in this Agreement or to such other address or email address as may be notified by that Party for this purpose and shall be effective notwithstanding any change of
address or email addresses not notified. 

 Addresses for notice: 

 

			
	For Celyad	  	For Horizon
		
	 Edouard Belin 2
 1435 Mont-Saint-Guibert

Belgium
  

E-mail: pdechamps@celyad.com

Attention: Philippe Dechamps
 (Chief Legal Officer)
	  	 8100 Cambridge Research Park
 Waterbeach

Cambridge CB25 9TL
  

E-mail: legal-contracts@horizondiscovery.com

Attention: Legal Counsel

  

	22.2.	 Unless proved otherwise, a notice shall be deemed to have been served, if: (i) sent by standard
mail service, forty-eight (48) hours after the date of posting; (ii) if by courier on the date of delivery provided that a valid and appropriately signed delivery receipt can be exhibited by the serving Party on request; and (iii) if
delivered by hand or sent by email during Business Hours, when left at the relevant address or transmitted (as applicable), and otherwise, if delivered after Business Hours, on the next Business Day. 

 

	23.	 Waiver 

  

	23.1.	 Any term or condition of this Agreement may be waived at any time by the Party that is entitled to the
benefit thereof, but no such waiver shall be effective unless set forth in a written instrument duly executed by or on behalf of the Party waiving such term or condition. 

 

	23.2.	 No reasonable delay or forbearance by any Party in exercising any right or remedy arising under this
Agreement shall operate as a waiver of it, nor shall any single or partial exercise of any right or remedy preclude any other or further exercise of it or the exercise of any other right or remedy. 

 

	24.	 Whole Agreement and Non-reliance 

 

	24.1.	 Without prejudice to the MNDA, this Agreement supersedes any previous written or oral agreement between
the Parties in relation to the matters dealt with in this Agreement that has not been expressly maintained by this Agreement and contains the whole agreement between the Parties relating to the subject matter of this Agreement as of the Effective
Date to the exclusion of any terms implied by law which may be excluded by contract. 

  
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	25.	 Variation 

No variation of this Agreement shall be effective unless in writing and signed by or on behalf of each of the Parties. 

 

	26.	 Expenses 

Each Party will bear its own expenses (including legal and accounting fees) associated with negotiating and executing this Agreement. Neither
Party will be liable for the other Party’s expenses. 
  

	27.	 No Partnership 

Nothing in this Agreement shall create a partnership or joint venture between the Parties to it and neither Party shall enter into or have
authority to enter into any engagement or make any representation or warranty on behalf of or pledge the credit of or otherwise bind or oblige the other Party hereto. 
  

	28.	 Further Assurance 

At any time after the Effective Date, the Parties shall, and shall use all reasonable endeavors to procure that any necessary Third Party
shall, execute such documents and do such acts and things as may reasonably be required for the purpose of giving either Party the full benefit of all the provisions of this Agreement. 

 

	29.	 Severance 

If any provision in this Agreement shall be held to be illegal, invalid or unenforceable, in whole or in part, under any enactment or rule of
law, such provision or part shall to that extent be deemed not to form part of this Agreement but the legality, validity and enforceability of the remainder of this Agreement shall not be affected. 

 

	30.	 Force Majeure 

 

	30.1.	 The obligations of each Party under this Agreement shall be suspended during the period and to the
extent that such Party is prevented from or hindered in complying with it or them by any cause which is unforeseeable, beyond its reasonable control and which renders impossible the performance of its obligations. Events of force majeure are
identified with reference to the Applicable Law and case law in the Territory and may include, as the case may be and without limitation, strikes, lock-outs, act of God, war, explosions, threat of war, riot, civil commotion, partial or total traffic
congestion, legal or governmental decisions, civil disturbances, civil or military order, hacking and virus attacks, malicious damage, break-down of plant or machinery, fire, flood or storm. 

 

	30.2.	 If any such cause or event prevents a Party from or hinders a Party in complying with its obligations
under this Agreement for a continuous period of three (3) months, the other Party shall have the right to terminate this Agreement on giving the Party under force majeure one (1) month written notice. This Agreement will automatically
terminate on expiry of said one (1) month period unless, during that period, the Party under force majeure is no longer prevented from or hindered in complying with its obligations hereunder and is, before the end of that period, again
complying with its obligations. 

  
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	31.	 Governing Law 

This Agreement, the documents to be entered into pursuant to it, and any non-contractual obligations
arising out of or in connection with them, shall be governed by and construed in accordance with English law. 
  

	32.	 Arbitration 

Any dispute or difference arising out of or under or in connection with this Agreement and the documents to be entered into pursuant to it, and
any non-contractual obligations arising out of or in connection with them, shall be finally settled under the Rules of Arbitration of the International Chamber of Commerce by three (3) arbitrators. The
award rendered shall be final and binding upon both parties. Such arbitration shall have its seat in The Hague and be conducted in the English language. 

Signed by the Parties or their duly authorized representatives, in two (2) original copies, each of the Parties acknowledging to have received one
(1). 
  

			
	 Celyad SA, represented by,
  

/s/ Christian Homsy
	  	 Horizon Discovery Limited, represented by,
  

/s/ Terry Pizzie

		
	 Name: Christian Homsy
 Title: Chief Executive
Officer
 Date: 3 April 2018
	  	 Name: Terry Pizzie
 Title: Director

Date: 3 April 2018

 Schedules: 
 Schedule 1
– Horizon Intellectual Property Rights 
 Schedule 2 – Research Plan 

  
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 Schedule 1 – Horizon Intellectual Property Rights 

[***] 

  
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 Schedule 2 – Research Plan 

[***] 

  
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 Schedule 3 – List of potentially relevant patents that Horizon believes may be in
force, together 
 with their expiry dates 

[***] 

  
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