Celyad Oncology (CLYYF) 20-F 23 Mar 23 2022 FY Annual report (foreign) Financial data

Cover Page

Cover Page - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Document Registration Statement	false
Document Annual Report	true
Document Transition Report	false
Document Shell Company Report	false
Entity Registrant Name	CELYAD ONCOLOGY SA
Entity Central Index Key	0001637890
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding	22,593,956
ICFR Auditor Attestation Flag	false
Entity File Number	001-37452
Document Accounting Standard	International Financial Reporting Standards
Entity Incorporation, State or Country Code	C9
Entity Address, Address Line One	Rue Edouard Belin 2
Entity Address, City or Town	Mont-Saint-Guibert
Entity Address, Country	BE
Entity Address, Postal Zip Code	1435
Auditor Name	EY Bedrijfsrevisoren SRL/BV	EY Bedrijfsrevisoren SRL/BV
Auditor Firm ID	1467	1467
Auditor Location	Belgium	Belgium
Business Contact [Member]
Document Information [Line Items]
Contact Personnel Name	Michel Lussier
Entity Address, Address Line One	Rue Edouard Belin 2
Entity Address, City or Town	Mont-Saint-Guibert
Entity Address, Country	BE
Entity Address, Postal Zip Code	1435
City Area Code	32
Local Phone Number	10 394 100
Contact Personnel Fax Number	10 394 141
ADR [Member]
Document Information [Line Items]
Title of 12(b) Security	American Depositary Shares, each representing one ordinary share, no nominal value per share
Trading Symbol	CYAD
Security Exchange Name	NASDAQ
Ordinary shares [member]
Document Information [Line Items]
No Trading Symbol Flag	true
Title of 12(b) Security	Ordinary shares, no nominal value per share
Security Exchange Name	NASDAQ

Consolidated Statements of Fina

Consolidated Statements of Financial Position - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Statement of financial position [abstract]
NON-CURRENT ASSETS	€ 4,891	€ 45,651
Goodwill and Intangible assets	864	36,168
Property, Plant and Equipment	309	3,248
Non-current Trade and Other receivables	0	2,209
Non-current Grant receivables	3,454	3,764
Other non-current assets	264	262
CURRENT ASSETS	14,825	34,292
Trade and Other Receivables	1,118	668
Grant receivables	0	1,395
Other current assets	1,017	2,211
Short-term investments	0	0
Cash and cash equivalents	12,445	30,018
Assets held for sale	245	0
TOTAL ASSETS	19,716	79,943
EQUITY	4,317	43,639
Share Capital	78,585	78,585
Share premium	6,317	6,317
Other reserves	34,800	33,172
Capital reduction reserve	234,562	234,562
Accumulated deficit	(349,947)	(308,997)
NON-CURRENT LIABILITIES	4,973	22,477
Bank loans	0
Lease liabilities	118	1,730
Recoverable Cash advances (RCAs)	4,584	5,851
Contingent consideration payable and other financial liabilities	0	14,679
Post-employment benefits	13	53
Other non-current liabilities	258	164
CURRENT LIABILITIES	10,426	13,827
Bank loans	0	0
Lease liabilities	137	902
Recoverable Cash advances (RCAs)	437	362
Trade payables	4,752	6,611
Other current liabilities	5,100	5,952
TOTAL EQUITY AND LIABILITIES	€ 19,716	€ 79,943

Consolidated Statements of Inco

Consolidated Statements of Income (Loss) - EUR (€) € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Profit or loss [abstract]
Revenue		€ 0	€ 0	€ 5
Cost of sales
Gross profit		0	0	5
Research and Development expenses		(18,928)	(20,773)	(21,522)
General & Administrative expenses		(10,546)	(9,908)	(9,315)
Change in fair value of contingent consideration		14,679	847	9,228
Impairment of Oncology intangible assets		(35,084)	0	0
Other income		9,360	4,909	4,731
Other expenses		(338)	(1,466)	(114)
Operating Loss	[1]	(40,857)	(26,391)	(16,987)
Financial income		185	144	217
Financial expenses		(198)	(255)	(434)
Loss before taxes		(40,870)	(26,502)	(17,204)
Income taxes		(65)	(10)	0
Loss for the period	[2]	€ (40,935)	€ (26,512)	€ (17,204)
Weighted average number of shares outstanding		22,593,956	15,604,014	13,942,344
Basic and diluted loss per share (in €)		€ (1.81)	€ (1.7)	€ (1.23)
[1]The operating loss arises from the Company’s loss for the period before deduction of financial income, financial expenses and income taxes. The purpose of this measure by Management is to identify the Company’s results in connection with its operating activities.[2]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income / (Loss) - EUR (€) € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of comprehensive income [abstract]
Loss of the year	[1]	€ (40,935)	€ (26,512)	€ (17,204)
Other comprehensive income/(loss)
Items that will not be reclassified to profit and loss		(15)	554	(197)
Remeasurements of post-employment benefit obligations, net of tax		(15)	554	(197)
Items that may be subsequently reclassified to profit or loss		4	42	(5)
Currency translation differences		4	42	(5)
Other comprehensive income / (loss) for the period, net of tax		(11)	596	(202)
Total comprehensive loss for the period		(40,946)	(25,916)	(17,406)
Total comprehensive loss for the period attributable to Equity Holders	[1]	€ (40,946)	€ (25,916)	€ (17,406)
[1]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - EUR (€) € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flow from operating activities
Loss for the period	[1]	€ (40,935)	€ (26,512)	€ (17,204)
Non-cash adjustments
Intangibles - Amortization and impairment		613	217	197
Property, plant & equipment - Depreciation		827	1,303	1,635
Loss on disposal of Goodwill and Intangible assets		58	0	0
Loss on disposal of Property, plant and equipment		132	1	10
Gain on sales of Property, plant & equipment		0	0	(35)
Gain on sale of CTMU activities		(5,187)	0	0
Remeasurement of Leases		(169)	0	0
Provision for onerous contract		2,171	29	858
Change in fair value of contingent consideration payable and other financial liabilities		(14,679)	(847)	(9,228)
Impairment of Oncology intangible assets		35,084	0	0
Remeasurement of Recoverable Cash Advances (RCAs)		(1,447)	328	(933)
Grant income (RCAs and others)		(2,047)	(4,178)	(3,089)
Share-based payment expense		1,624	2,172	2,782
Post-employment benefits		(40)	(561)	216
Change in working capital
Trade receivables, other (non-)current receivables		306	(1,559)	(1,148)
Trade payables, other (non-)current liabilities		(4,321)	2,964	(1,726)
Net cash used in operations		(28,010)	(26,643)	(27,665)
Cash Flow from investing activities
Acquisition of Property, Plant & Equipment		(123)	(331)	(150)
Acquisitions of Intangible assets		0	(62)	(169)
Proceeds from disposals of Property, plant & equipment		0	0	235
Proceeds from net investment in lease		235	267	241
Proceeds from sale of CTMU activities		6,000	0	0
Proceeds from short-term investments		1,090
Net cash from/(used in) investing activities		7,202	(126)	157
Cash Flow from financing activities
Repayments of bank borrowings		0	(37)	(192)
Repayments of leases		(896)	(1,099)	(1,255)
Proceeds from issuance of shares and exercise of warrants		(124)	36,568
Proceeds from RCAs & other grants		4,491	4,369	7,272
Repayment of RCAs & other grants		(230)	(280)	(429)
Net cash from/(used in) financing activities		3,241	39,521	5,396
Net cash and cash equivalents at beginning of the period		30,018	17,234	39,338
Change in Cash and cash equivalents		(17,567)	12,752	(22,112)
Effects of exchange rate changes on cash and cash equivalents		(6)	32	8
Net cash and cash equivalents at the end of the period		€ 12,445	€ 30,018	€ 17,234
[1]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - EUR (€) € in Thousands	Total		Share capital [member]	Share premium [member]	Other reserves [member]	[1]	Capital reduction reserve [member]	[1]	Accumulated deficit [member]	[1]
Beginning balance at Dec. 31, 2019	€ 45,619		€ 48,513	€ 43,349	€ 28,181		€ 191,213		€ (265,637)
Share-based payments	2,782				2,782
Total transactions with owners, recognized directly in equity	2,782		0	0	2,782		0
Loss for the period	(17,204)	[2]							(17,204)
Currency Translation differences	(5)				(5)
Remeasurements of defined benefit obligation	(197)								(197)
Total comprehensive loss for the period	(17,406)				(5)				(17,402)
Ending balance at Dec. 31, 2020	30,994		48,513	43,349	30,958		191,213		(283,039)
Capital increase	38,972		30,072	8,900
Transaction costs associated with capital increases	(2,583)			(2,583)
Reduction of share premium by absorption of losses				(43,349)			43,349
Share-based payments	2,172				2,172
Total transactions with owners, recognized directly in equity	38,561		30,072	(37,032)	2,172		43,349
Loss for the period	(26,512)	[2]							(26,512)
Currency Translation differences	42				42
Remeasurements of defined benefit obligation	554								554
Total comprehensive loss for the period	(25,916)				42				(25,958)
Ending balance at Dec. 31, 2021	43,639		78,585	6,317	33,172		234,562		(308,997)
Share-based payments	1,624				1,624
Total transactions with owners, recognized directly in equity	1,624		0	0	1,624		0
Loss for the period	(40,935)	[2]							(40,935)
Currency Translation differences	4				4
Remeasurements of defined benefit obligation	(15)								(15)
Total comprehensive loss for the period	(40,946)				4				(40,950)
Ending balance at Dec. 31, 2022	€ 4,317		€ 78,585	€ 6,317	€ 34,800		€ 234,562		€ (349,947)
[1]Pursuant to Belgian law (“CCA”), the calculation of amounts available for distribution to shareholders, as dividends or otherwise, must be determined on the basis of the Company’s standalone non-consolidated statutory financial statements of Celyad Oncology SA prepared under Belgian GAAP, and not on the basis of IFRS consolidated financial statements. For more information, see Note 15.[2]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

The Company

The Company	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
The Company	NOTE 1: THE COMPANY Unless otherwise indicated, “Celyad,” “Celyad Oncology”, “the Company,” “our company,” “the Group,” “we,” “us” and “our” refer to Celyad Oncology SA and its consolidated subsidiaries. The Company is a biotechnology company focused on the research and development of chimeric antigen receptor T cell (CAR T) therapies for cancer. Celyad Oncology SA was incorporated on July 24, 2007, under the name “Cardio3 BioSciences”. Celyad is a limited liability company (Société Anonyme) governed by Belgian law with its registered office at Axis Parc, Rue Edouard Belin 2, B-1435 The Company’s ordinary shares are listed on NYSE Euronext Brussels and NYSE Euronext Paris regulated markets and the Company’s American Depositary Shares (ADSs) are listed on the Nasdaq Global Market, all under the ticker symbol CYAD. The Company has three fully owned subsidiaries (together, the Group) located in Belgium (Biological Manufacturing Services SA) and in the United States (Celyad Inc. and Corquest Medical, Inc.). These consolidated financial statements have been approved for issuance by the Company’s Board of Directors on March 23, 2023. These statements have been audited by EY Réviseurs d’Entreprises / EY Bedrijfsrevisoren SRL/BV, the statutory auditor of the Company and independent registered public accounting firm. The annual report is available to the public free of charge to the above-mentioned address or via the Company’s website ( https://celyad.com/investors/regulated-information/ Key event 2022 In September 2022, under the terms of an asset purchase agreement between the Company and Cellistic (the cell therapy development and manufacturing business of Ncardia BV), Cellistic agreed to acquire the Company’s Good Manufacturing Practice (GMP) grade cell therapy manufacturing facility, including the existing facility and all related personnel (the “Manufacturing Business Unit”, “Cell Therapy Manufacturing Unit”, or “CTMU”), in Mont-Saint-Guibert, Belgium, for a total consideration million and effective as of January 1, 2023, the Group sold certain fixed assets to Cellistic and the Group also leased part of the building from Cellistic. For more information on the financial consequences of this transaction, refer to notes 7, 8, 26, 28, 30 and 37. In October 2022, the Company announced its new business strategy “Celyad 2.0”, under which the Company intends to focus on maximizing its intellectual property (IP) portfolio and strengthening its research focus. Based on this strategic and financial review, the Company has decided to discontinue the development of its remaining clinical programs. Under Celyad 2.0, the Company shifts from an organization focused on clinical development to one prioritizing R&D discovery and the monetization of its IP portfolio through partnerships, collaborations and license agreements. For more information on the financial consequences of this decision, refer to notes 7, 21, 22, 23, 24, 26, 28 and 29.

General Information and Stateme

General Information and Statement of Compliance	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
General information and Statement of Compliance	NOTE 2: GENERAL INFORMATION AND STATEMENT OF COMPLIANCE The consolidated financial statements of the Group for the twelve months ended December 31, 2022, 2021 and 2020 (the “year” or “the period”) include Celyad Oncology SA and its subsidiaries. The significant accounting policies used for preparing these consolidated financial statements are explained below. Basis of preparation The consolidated financial statements have been prepared on an historical cost basis, except for: • Financial instruments – Fair value through profit or loss • Contingent consideration and other financial liabilities • Post-employment benefits liability The policies have been consistently applied to all the years presented, unless otherwise stated. The consolidated financial statements are presented in euro and all values are presented in thousands (€000) except when otherwise indicated. Amounts have been rounded off to the nearest thousand and in certain cases, this may result in minor discrepancies in the totals and sub-totals Statement of compliance The consolidated financial statements of the Group have been prepared in accordance with International Financial Reporting Standards, International Accounting Standards and Interpretations (collectively, IFRSs) as issued by the International Accounting Standards Board (IASB). The preparation of the consolidated financial statements in accordance with IFRS requires the use of certain critical accounting estimates. It also requires management to exercise its judgment in the process of applying the Group’s accounting policies. The areas involving a higher degree of judgment or complexity, are areas where assumptions and estimates are significant to the financial statements. They are disclosed in note 5. Going concern The Group is pursuing a strategy to develop products and platforms that will help our partners to treat medical needs in oncology. Management has prepared detailed budgets and cash flow forecasts for the years 2023 and 2024. These forecasts reflect the new strategy of the Group and include significant expense and cash outflow estimations in relation to the development of its proprietary technology platforms and intellectual property, partly compensated by grants funding and tax incentives. As of December 31, 2022, the Company had cash and cash equivalents of €12.4 million and no short-term investments. The Company projects that its existing cash and cash equivalents should be sufficient to fund operating expenses and capital expenditure requirements into the fourth quarter of 2023. After due consideration of detailed budgets and estimated cash flow forecasts for the years 2023 and 2024, the Company projects that its existing cash and cash equivalents will not be sufficient to fund its estimated operating and capital expenditures over at least the next 12 months from the date that the financial statements are issued. The Company is currently evaluating different financing options to obtain the required funding to extend the Company’s cash runway beyond 12 months from the date the financial statements are issued. Financing options may include, but are not limited to, the public or private sale of equity, debt financings or funds from other capital sources, such as collaborations, strategic alliances and partnerships, or licensing arrangements with third parties. However, there can be no assurance that the Company will be able to secure additional financing, or if available, that it will be sufficient to meet its needs or available on favorable terms indicating a material uncertainty exists about the Company’s ability to continue as a going concern. The accompanying consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. Accordingly, the consolidated financial statements have been prepared on a basis that assumes the Company will continue as a going concern and contemplates the realization of assets and satisfaction of liabilities and commitments in the ordinary course of business. COVID-19 The long-term impact of COVID-19 COVID-19’s COVID-19 War in Ukraine In February 2022, Russia launched a military invasion of Ukraine. The ongoing military operations in Ukraine and the related sanctions targeted against Russia and Belarus may have an impact on the European and global economies. The Company has no operations or suppliers based in Ukraine, Belarus, or Russia, and consequently there has not been a negative impact on our operations to date. However, the general economic impacts of the conflict are unpredictable and could lead to market disruptions, including significant volatility in commodity prices, credit and capital markets. Given the continuing conflict, the operations of the Company could be disrupted due to the demise of commercial activity in impacted regions and due to the severity of sanctions on the businesses upon which the Company and its suppliers rely. Further, state-sponsored cyberattacks could expand as part of the conflict, which could adversely affect our ability to maintain or enhance key cyber security and data protection measures. To date, the Company has not experienced any material adverse impacts, but the Company is not able to reliably predict the potential impact of the conflict on its future business or operations. Changes to accounting standards and interpretations The Group has applied the same accounting policies and methods of computation in its 2022 year-end None of the new standards, interpretations and amendments, which are effective for periods beginning after January 1, 2022 which have been issued by the IASB have a material effect on the Group’s financial statements. None of the new standards, interpretations and amendments, which will be effective for periods beginning after January 1, 2023 and are not yet effective as of December 31, 2022 and/or not yet adopted by the European Union as of December 31, 2022, are expected to have a material effect on the Group’s future financial statements as either they are not relevant to the Group’s activities, or they require accounting which is consistent with the Group’s current accounting policies.

Accounting Principles

Accounting Principles	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Accounting Principles	NOTE 3: ACCOUNTING PRINCIPLES Subsidiaries Subsidiaries are all entities (including structured entities) over which the Group has control. The Group controls an entity when the Group is exposed to, or has rights to, variable returns from its involvement with the entity and has the ability to affect those returns through its power over the entity. Subsidiaries are fully consolidated from the date on which control is transferred to the Group. They are deconsolidated from the date control ceases. Inter-company transactions, balances and unrealized gains on transactions between group companies are eliminated. Unrealized losses are also eliminated. When necessary, amounts reported by subsidiaries have been adjusted to conform with the Group’s accounting policies. FOREIGN CURRENCY TRANSLATION Functional and presentation currency Items included in the financial statements of each of the Group’s entities are measured using the currency of the primary economic environment in which the entity operates (“the functional currency”). The consolidated financial statements are presented in Euros, which is the Group’s presentation currency. Transactions and balances Foreign currency transactions (mainly USD) are translated into the functional currency using the applicable exchange rate on the transaction dates. Monetary assets and liabilities denominated in foreign currencies are retranslated at the presentation currency spot rate of exchange ruling at the reporting date. Foreign currency exchange gains and losses arising from settling foreign currency transactions and from the retranslation of monetary assets and liabilities denominated in foreign currencies at the reporting date are recognized in the income statement. Non-monetary Non-monetary Group companies The results and financial position of all group entities that have a functional currency different from the presentation currency are translated into the presentation currency as follows: • Assets and liabilities for each statement of financial position presented are translated at the closing rate at the date of that statement of financial position; • Income and expenses for each income statement are translated at average exchange rate (unless this average is not a reasonable approximation of the cumulative effect of the rates prevailing on the transaction dates, in which case income and expenses are translated at the rate on the dates of the transactions); and • All resulting translation differences are recognized in other comprehensive income. REVENUE So far, the primary revenue generated by the Group relates to the sale of licenses. Licensing revenue The Group enters into license and/or collaboration agreements with third-party biopharmaceutical partners. Revenue under these arrangements may include non-refundable Upfront payments License fees representing non-refundable Milestone payments Milestone payments represent amounts received from the Group’s customers or collaborators, the receipt of which is dependent upon the achievement of certain scientific, regulatory, or commercial milestones. Under IFRS 15, milestone payments generally represent a form of variable consideration as the payments are likely to be contingent on the occurrence of future events. Milestone payments are estimated and included in the transaction price based on either the expected value (probability-weighted estimate) or most likely amount approach. The most likely amount is likely to be most predictive for milestone payments with a binary outcome (i.e., the Group receives all or none of the milestone payment). Variable consideration is only recognized as revenue when the related performance obligation is satisfied, and the Group determines that it is highly probable that there will not be a significant reversal of cumulative revenue recognized in future periods. Royalty revenue Royalty revenues arise from the Group’s contractual entitlement to receive a percentage of product sales achieved by co-contracting co-contracting Sales of goods (medical devices) Sales of medical devices are recognized when the Group has fulfilled the performance obligations under the terms of the sales contract, which includes delivery of the promised goods. OTHER INCOME Government Grants The Group’s grant income reported under ‘Other income’ in the consolidated statement of comprehensive loss is generated from: (i) recoverable cash advances (RCAs) granted by the Regional government of Wallonia; (ii) R&D tax credits granted by the Belgian federal government; and (iii) grants received from the European Commission under the Seventh Framework Program (“FP7”), Federal Belgian Institute for Health Insurance (Inami) and Regional authorities. Government grants are recognized at their fair value (calculated based on present value of future repayment of grants) where there is reasonable assurance that the grant will be received, and the Group has complied with all attached conditions. Once a government grant is recognized, any related contingent liability (or contingent asset) is treated in accordance with IAS 37. Government grants relating to costs are deferred and recognized in the consolidated statement of comprehensive loss over the period necessary to match them with the costs that they are intended to compensate. Based on the nature of transactions, cash inflows received from government grants provide the entity with financing for the designated activity. They are in substance financing cash inflows consistent with the cash proceeds from RCAs and other grants and are disclosed in the consolidated statements of cash flows as “Cash Flow from financing activities”. The Group’s grant income is recognized in the consolidated statement of comprehensive loss under “Other income/expense” and as a non-cash Recoverable cash advances (RCAs) The Group receives grants from the Walloon Region in the form of recoverable cash advances (RCAs). RCAs are dedicated to support specific development programs. All RCA contracts, in essence, consist of three phases, i.e., the “research phase”, the “decision phase” and the “exploitation phase”. During the research phase, the Group receives funds from the Region based on statements of expenses. In accordance with IAS 20.10A and IFRS Interpretations Committee (IC)’s conclusion that contingently repayable cash received from a government to finance a research and development (R&D) project is a financial liability under IAS 32, ‘Financial instruments; Presentation’, the RCAs are initially recognized, concomitantly with the occurrence of subsidized expense, as a financial liability at fair value (calculated based on present value of future repayment of grants), determined as per IFRS 9. The benefit (RCA grant component) consisting in the difference between the cash received (RCA proceeds) and the above-mentioned financial liability’s fair value (RCA liability component) is treated as a government grant in accordance with IAS 20. The RCA grant component is recognized in profit or loss under “Other income” on a systematic basis over the periods in which the entity recognizes the underlying R&D expenses subsidized by the RCA. The fair market value adjustments to the RCA liability are recognized in the consolidated statement of comprehensive loss under “Other income/expense” and as a non-cash The RCAs liability contains two components: • The fixed part of the reimbursement of 30% is refundable based upon an agreed repayment schedule. The initial recognition at fair value is performed using the discount rate at the date of the convention and the assumption of exploitation until the end of repayment schedule. • The variable part (from 70% and up to 170%) is refundable to the extent of the revenue generated within exploitation phase. The initial recognition at fair value of the variable part of the component is based on probability-weighted discounted cash flows estimated using Key assumptions listed in note 7. The sales-independent reimbursements and sales-dependent reimbursements are, in the aggregate (including the accrued interests), capped at 200% of the principal amount paid out by the Walloon Region. The RCAs liability component (RCA financial liability) is subsequently measured at amortized cost using the cumulative catch-up At the end of the research phase, the Group should within a period of six months decide whether or not to exploit the results of the research phase (decision phase). The exploitation phase may have a duration of up to 20 years. In the event the Group decides to exploit the results under an RCA, the relevant RCA becomes contingently refundable, and the fair value of the RCA liability adjusted accordingly, if required. For more information on the potential financial consequences of these exploitation decisions in terms of potential reimbursements and sales percentage When the Group does not exploit (or ceases to exploit) the results of programs under an RCA, it has to notify the Region of this decision. This decision is the sole responsibility of the Group. The related liability is then discharged by the transfer of such results to the Region. Also, when the Group decides to renounce its rights to patents which may result from the research, title to such patents will be transferred to the Region. In that case, the RCA liability is extinguished and reflected in the statement of income (loss) under “Other income/expense”. R&D Tax credits Since 2013, the Group applies for R&D tax credits, a tax incentive measure for European SME’s established by the Belgian federal government. When capitalizing its R&D expenses under the tax reporting framework, the Group may either i) get a reduction of its taxable income (at current income tax rate applicable); or ii) if no sufficient taxable income is available, apply for the refund of the unutilized tax credits, calculated on the R&D expenses amount for the year. Such settlement occurs at the earliest 5 financial years after the tax credit application filed by the Group. Considering that R&D tax credits are ultimately paid by the public authorities, the related benefit is treated as a government grant under IAS 20 and booked into other income, in order to match the R&D expenses subsidized by the grant. Other government grants The Group has received and will continue to apply for grants from European (FP7), Regional authorities and Federal Belgian Institute for Health Insurance (Inami). These grants are dedicated to partially finance early stage projects such as fundamental research, applied research, prototype design, etc. To date, all grants received are not associated with any conditions. As per each grant agreement, grants are paid upon submission by the Group of a statement of eligible expenses. The Group incurs expenses first and then submits application for the grant receipt according to the terms of the grant agreement. These government grants are recognized in profit or loss under “Other income” on a systematic basis over the periods in which the entity recognizes the underlying R&D expenses subsidized. INTANGIBLE ASSETS The following categories of intangible assets apply to the current Group operations: Separately acquired intangible assets Intangible assets acquired from third parties are recognized at cost, if and only if it is probable that future economic benefits associated with the asset will flow to the Group, and that the cost can be measured reliably. Subsequent payments of contingent consideration are capitalized when incurred. Following initial recognition, intangible assets are carried at cost less any accumulated amortization and accumulated impairment losses. The useful life of intangible assets is assessed as finite, except for Goodwill. They are amortized over the expected useful economic life and assessed for impairment whenever there is an indication that the intangible asset may be impaired. The amortization period and the amortization method for an intangible asset with a finite useful life are reviewed at least at each financial year end. Changes in the expected useful life or the expected pattern of consumption of future economic benefits embodied in the asset are accounted for by changing the amortization period or method, as appropriate, and are treated as changes in accounting estimates and applied prospectively. The amortization expense on intangible assets with finite lives is recognized in the income statement in the expense category consistent with the function of the intangible asset. Patents, Licenses and Trademarks Licenses for the use of intellectual property are granted for a period corresponding to the intellectual property of the assets licensed. Amortization is calculated on a straight-line basis over this useful life. Patents and licenses are amortized over the period corresponding to the intellectual property (IP) protection and are assessed for impairment whenever there is an indication these assets may be impaired. Indication of impairment is related to the value of the patent demonstrated by the preclinical and clinical results of the technology. Software Software only concerns acquired computer software licenses. Software is capitalized on the basis of the costs incurred to acquire and bring to use the specific software. These costs are amortized over their estimated useful lives of three five years Intangible assets acquired in a business combination Goodwill Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Goodwill is measured as a residual at the acquisition date, as the excess of the fair value of the consideration transferred and the assets and liabilities recognized (in accordance with IFRS 3). Goodwill has an indefinite useful life and is not amortized but tested for impairment at least annually or more frequently whenever events or changes in circumstances indicate that goodwill may be impaired, as set forth in IAS 36 (Impairment of Assets). Goodwill arising from business combinations is allocated to cash generating units, which are expected to receive future economic benefits from synergies that are most likely to arise from the acquisition. These cash generating units form the basis of any future assessment of impairment of the carrying value of the acquired goodwill. In-process The In-process Subsequent R&D expenditure can be capitalized as part of the IPR&D only to the extent that IPR&D is in development stage, i.e., when such expenditure meets the recognition criteria of IAS 38. In line with biotech industry practice, the Group determines that ‘development stage’ under IAS 38 is reached when the product candidate gets regulatory approval (upon Phase III completion). Therefore, any R&D expenditure incurred between the acquisition date and the development stage should be treated as part of research phase and expensed periodically in the income statement. Internally generated intangible assets Except qualifying development expenditure (discussed below), internally generated intangible assets are not capitalized. Expenditure is reflected in the income statement in the year in which the expenditure is incurred. Research and development costs Research costs are expensed as incurred. Development expenditures on an individual project are recognized as an intangible asset when the Group can demonstrate: a) The technical feasibility of completing the intangible asset so that it will be available for use or sale. b) Its intention to complete the intangible asset and use or sell it. c) Its ability to use or sell the intangible asset. d) How the intangible asset will generate probable future economic benefits. Among other things, the entity can demonstrate the existence of a market for the output of the intangible asset or the intangible asset itself or, if it is to be used internally, the usefulness of the intangible asset. e) The availability of adequate technical, financial and other resources to complete the development and to use or sell the intangible asset. f) Its ability to measure reliably the expenditure attributable to the intangible asset during its development. For the industry in which the Group operates, the life science industry, criteria a) and d) tend to be the most difficult to achieve. Experience shows that in the Biotechnology sector technical feasibility of completing the project is met when such project completes successfully Phase III of its development. For medical devices this is usually met at the moment of CE marking. Following initial recognition of the development expenditure as an asset, the cost model is applied requiring the asset to be carried at cost less any accumulated amortization and accumulated impairment losses. Amortization of the asset begins when development has been completed and the asset is available for use. It is amortized over the period of expected future benefit. Amortization is recorded in Research & Development expenses. During the period of development, the asset is tested for impairment annually, or earlier when an impairment indicator occurs. As of statement of financial position dates, only the development costs of C-Cathez under “Development costs” PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment is stated at cost, net of accumulated depreciation and/or accumulated impairment losses, if any. Repair and maintenance costs are recognized in the income statement as incurred. Depreciation is calculated on a straight-line basis over the estimated useful life of the asset as follows: • Land and buildings: 15 to 20 years • Plant and equipment: 5 to 15 years • Laboratory equipment: 3 to 5 years • Office furniture: 3 to 10 years • Leasehold improvements: based on remaining duration of office building lease • Right-of-use An item of property, plant and equipment and any significant part initially recognized is derecognized upon disposal or when no future economic benefits are expected from its use or disposal. Any gain or loss arising on derecognition of the asset (calculated as the difference between the net disposal proceeds and the carrying amount of the asset) is included in the income statement when the asset is derecognized. The assets’ residual values, useful lives and methods of depreciation are reviewed at each financial year end, and adjusted prospectively, if applicable. LEASES The determination of whether an arrangement is, or contains, a lease is based on the substance of the arrangement at inception date whether fulfilment of the arrangement is dependent on the use of a specific asset or assets, or the arrangement conveys a right to use the asset. The Group leases various offices, facilities, cars and IT-equipment. Leases are recognized as a right-of-use asset, presented under “Property, Plant and Equipment”, and a corresponding liability at the date at which the leased asset is available for use by the Group. Each lease payment is allocated between the liability and finance cost. The finance cost is charged to profit or loss over the lease period so as to produce a constant periodic rate of interest on the remaining balance of the liability for each period. The right-of-use asset is depreciated over the shorter of the asset’s useful life and the lease term on a straight-line basis. Assets and liabilities arising from a lease are initially measured on a present value basis. Lease liabilities include the net present value of the following lease payments: • Fixed payments (including in-substance • Variable lease payment that are based on an index or a rate; • Amounts expected to be payable by the lessee under residual value guarantees; • The exercise price of a purchase option if the lessee is reasonably certain to exercise that option; and • Payments of penalties for terminating the lease, if the lease term reflects the lessee exercising that option. The lease term covers the non-cancellable (a) Periods covered by an option to extend the lease if the Group is reasonably certain to exercise that option; and (b) Periods covered by an option to terminate the lease if the Group is reasonably certain not to exercise that option. The lease payments are discounted using the interest rate implicit in the lease. If that rate cannot be determined, the lessee’s incremental borrowing rate is used, being the rate that the lessee would have to pay to borrow the funds necessary to obtain an asset of similar value in a similar economic environment with similar terms and conditions. Right-of-use • The amount of the initial measurement of lease liability; • Any lease payments made at or before the commencement date less any lease incentives received; • Any initial direct costs; and • Restoration costs. Payments associated with short-term leases and leases of low-value Low-value IT-equipment. Until September 2022, the Group subleased some office space it leases from a head lessor. In its capacity as intermediate lessor, the Group assesses whether the sublease is a finance or operating lease in the context of the right-of-use right-of-use right-of-use From time to time, the Group may enter into sale and leaseback transactions. When a sale occurs, both the seller-lessee and the buyer-lessor account for the leaseback in the same manner as any other lease. Specifically, the seller-lessee recognizes a lease liability and right-of-use low-value IMPAIRMENT OF NON-FINANCIAL The Group assesses at each reporting date whether there is an indication that an asset may be impaired, unless there are indications of impairment at other points throughout the period. If any indication exists, or when annual impairment testing for an asset is required, the Group estimates the asset’s recoverable amount. An asset’s recoverable amount is the higher of an asset’s or cash-generating unit’s (CGU) fair value less costs to sell and its value in use and is determined for an individual asset, unless the asset does not generate cash inflows that are largely independent of those from other assets or group of assets. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax Where the carrying amount of an asset or CGU exceeds its recoverable amount, an impairment loss is immediately recognized as an expense and the asset carrying value is written down to its recoverable amount. An assessment is made at each reporting date as to whether there is any indication that previously recognized impairment losses may no longer exist or may have decreased. If such indication exists, the Group estimates the asset’s or cash-generating unit’s recoverable amount. A previously recognized impairment loss is reversed only if there has been a change in the assumptions used to determine the asset’s recoverable amount since the last impairment loss was recognized. The reversal is limited so that the carrying amount of the asset does not exceed its recoverable amount, nor exceed the carrying amount that would have been determined, net of depreciation, had no impairment loss been recognized for the asset in prior years. Such reversal is recognized in the income statement unless the asset is carried at a revalued amount, in which case the reversal is treated as a revaluation increase. An impairment loss recognized on goodwill is however not reversed in a subsequent period. As of the statement of financial position dates, the Group has two cash-generating units which consist of the development and commercialization activities on: • CYAD products candidate series based on CAR T technology, for the immune-oncology segment; and • C-Cath ez Indicators of impairment used by the Group are the preclinical and clinical results obtained with the technology. CASH AND CASH EQUIVALENTS Cash and cash equivalents in the statement of financial position comprise cash at banks and on hand and very short-term deposits with an original maturity of three months or less. Cash and cash equivalents are carried in the statement of financial position at their nominal value. FINANCIAL ASSETS Classification The Group classifies its financial assets in accordance with IFRS 9 categories for measurement purposes. The classification depends on the purpose for which the financial assets were acquired. Management determines the classification of its financial assets at initial recognition. ‘Amortized cost’ measurement category refers to loans and receivables which are non-derivative non-current “(non-) “(non-) (non-) Initial recognition and measurement All financial assets are recognized initially at fair value plus or minus, in the case of a financial asset not at fair value through profit or loss, directly attributable transaction costs. Subsequent measurement After initial measurement, financial assets are subsequently measured at amortized cost using the effective interest rate method (EIR), less impairment. Amortized cost is calculated by taking into account any discount or premium on acquisition and fee or costs that are an integral part of the EIR. The EIR amortization is included in finance income in the income statement under “Financial income”. The losses arising from impairment are recognized in the income statement under “Other expenses”. Impairment of financial assets In relation to the impairment of financial assets, IFRS 9 requires an expected credit loss model. The expected credit loss model requires the Group to account for expected credit losses and changes in those expected credit losses at each reporting date to reflect changes in credit risk since initial recognition of the financial assets. In other words, it is no longer necessary for a credit event to have occurred before credit losses are recognized. The Group considers there is no significant additional credit risk related to this receivable, which would not have been captured by the discounting effect, both at inception of the receivable and at the reporting date. As such, no additional ECL allowance has been recognized for this financial asset or any other financial asset. Financial assets carried at amortized cost For financial assets carried at amortized cost the Group first assesses individually whether objective evidence of impairment exists individually for financial assets that are individually significant, or collectively for financial assets that are not individually significant. If the Group determines that no objective evidence of impairment exists for an individually assessed financial asset, it includes the asset in a group of financial assets with similar credit risk characteristics and collectively assesses them for impairment. Assets that are individually assessed for impairment and for which an impairment loss is, or continues to be, recognized are not included in a collective assessment of impairment. If there is objective evidence that an impairment loss has been incurred, the amount of the loss is measured as the difference between the asset’s carrying amount and the present value of estimated future cash flows. The present value of the estimated future cash flows is discounted at the financial assets’ original effective interest rate. If a loan has a variable interest rate, the discount rate for measuring any impairment loss is the current effective interest rate. The carrying amount of the asset is reduced through the use of an allowance account and the amount of the loss is recognized in the income statement under “Other expenses”. Interest income continues to be accrued on the reduced carrying amount and is accrued using the rate of interest used to discount the future cash flows for the purpose of measuring the impairment loss. The interest income is recorded as part of finance income in the income statement under “Financial income”. Loans together with the associated allowance are written off when there is no realistic prospect of future recovery. If, in a subsequent year, the amount of the estimated impairment loss increases or decreases because of an event occurring after the impairment was recognized, the previously recognized impairment loss is increased or reduced by adjusting the allowance account. If a future write-off FINANCIAL LIABILITIES Classification The Group’s financial liabilities include “bank loans”, “lease liabilities”, “recoverable cash advances”, “contingent consideration and other financial liabilities”, “trade payables” and relevant financial liabilities within “Other (non-) The Group classifies and measures its financial liabilities at ‘amortized cost’ using the effective interest method, except “contingent consideration and other financial liabilities” which are classified and measured at ‘fair value through profit or loss’. Initial recognition and measurement Financial liabilities are initially measured at fair value. Transactions costs that are directly attributable to the acquisition or issue of financial liabilities are added or deducted from the fair value of the financial liabilities, as appropriate, on initial recognition. Subsequent measurement The subsequent measurement of financial liabilities depends on their classification as explained above. In particular: Contingent consideration The contingent consideration and other financial liabilities are recognized and measured at fair value at the acquisition date. After initial recognition, contingent consideration arrangements that are classified as liabilities are re-measured Details regarding the valuation of the contingent consideration are disclosed in note 23. Recoverable cash advances Recoverable cash advances granted by the Walloon Region are subsequently measured at amortized cost using the cumulative catch-up Trade payables and other payables After initial recognition, trade payables and other payables are measured at amortized cost using the effective interest method. Loans and borrowings After initial recognition, interest bearing loans and borrowings are subsequently measured at amortized cost using the effective interest rate method. Gains and losses are recognized in the income statement when the liabilities are derecognized. Derecognition A financial liability is derecognized when the obligation under the liability is discharged or cancelled or expires. When an existing financial liability is replaced by another from the same lender on substantially different terms, or the terms of an existing liability are substantially modified, such an exchange or modification is treated as a derecognition of the original liability and the recognition of a new liability, and the difference in the respective carrying amounts is recognized in the income statement under “Change in fair value of contingent consideration” or “Other expenses”. PROVISIONS Provisions are recognized when the Group has a present obligation (legal or constructive) as a result of a past event, it is probable that an outflow of resources embodying economic benefits will be required to settle the obligation and a reliable estimate can be made of the amount of the obligation. Where the Group expects some or all of a provision to be reimbursed, for example under an insurance contract, the reimbursement is recognized as a separate asset but only when the reimbursement is virtually certain. The expense relating to any provision is presented in the income statement net of any reimbursement. If the effect of the time value of money is material, provisions are discounted using a current pre-tax Employee benefits Post-employment plan The Group operates a pension plan which requires defined contributions (DC) to be funded by the Group externally at a third-party insurance company. Under Belgian law, an employer must guarantee a minimum rate of return on the Group’s contributions and thus it is treated as defined benefit plan under IAS 19. Therefore, any pension plan (including DC plans) organized in Belgium is treated as defined benefit plans under IAS 19. At the statement of financial position dates, the minimum rates of return guaranteed by the Group are as follows, in accordance with the law of 18 December 2015: • 1.75% for the employer’s contributions paid as from 1 January 2016 (variable rate based on Governmental bond OLO rates, with a minimum of 1.75% and a maximum of 3.75%); • 3.25% (fixed rate) for the employer’s contributions paid until 31 December 2015. The cost of providing benefits is determined using the projected unit credit (PUC) method, with actuarial valuations being carried out at the end of each annual reporting period, with the assistance of an independent actuarial firm. The liability recognized in the statement of financial position in respect of the pension plans is the present value of the defi

Risk Management

Risk Management	12 Months Ended
	Dec. 31, 2022
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Risk Management	NOTE 4: RISK MANAGEMENT Financial risk factors Interest rate risk The interest rate risk is very limited as the Group has only a limited amount of finance leases and no outstanding bank loans. So far, because of the immateriality of the exposure, the Group did not enter into any interest hedging arrangements. Credit risk The Group has a limited amount of trade receivables due to the fact that sales to third parties are not significant and thus the Group’s credit risk arises mainly from cash and cash equivalents and deposits with banks and financial institutions. The Group only works with international reputable commercial banks and financial institutions. The maximum credit risk, to which the Group is theoretically exposed as at the statement of financial position date, is the carrying amount of financial assets. Given the current nature and size of operations of the Group, the requirement of the Group to measure the loss allowance for a financial instrument at an amount equal to the lifetime expected credit losses (ECL), mainly apply to trade and other receivables (resulting mainly from the amendment of the Mesoblast license agreement). The Group recognized a bad debt accrual on this receivable at the reporting date and considers there is no significant additional credit risk related to this receivable. As such, no additional ECL allowance has been recognized for this asset or any other financial asset. Foreign exchange risk The Group is exposed to foreign exchange risk as certain collaborations or supply agreements of raw materials are denominated in USD. Moreover, the Group has also investments in foreign operations, whose net assets are exposed to foreign currency translation risk (USD). So far, because of the immateriality of the exposure, the Group did not enter into any currency hedging arrangements. At December 31, 2022, the foreign exchange risk exposure exists mainly on the cash denominated in USD. A depreciation of 1% on the USD versus EUR would translate into an unrealized foreign exchange loss of €9k for the Group at December 31, 2022. Liquidity risk The Group monitors its risk to a shortage of funds using a recurring liquidity planning tool. Refer to note 5 for the going concern assessment. The Group’s objective is to maintain a balance between continuity of funding and flexibility through the use of bank deposit and leases. Refer to note 23 for an analysis of the Group’s non-derivative Capital management The Group’s objectives when managing capital are to safeguard the Group’s ability to continue as a going concern in order to provide returns for shareholders and benefits for other stakeholders and to maintain an adequate structure to limit to cost of capital.

Critical accounting estimates a

Critical accounting estimates and judgments	12 Months Ended
	Dec. 31, 2022
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Critical accounting estimates and judgments	NOTE 5: CRITICAL ACCOUNTING ESTIMATES AND JUDGMENTS The preparation of the Group’s financial statements requires Management to make judgments, estimates and assumptions that affect the reported amounts of revenues, expenses, assets and liabilities, and the disclosure of contingent liabilities, at the end of the reporting period. Estimates and judgments are continually evaluated and are based on historical experience and other factors, including expectations of future events that are believed to be reasonable under the circumstances. Uncertainty about these assumptions and estimates could result in outcomes that require a material adjustment to the carrying amount of the asset or liability affected in future periods. In the process of applying the Group’s accounting policies, Management has made judgments and has used estimates and assumptions concerning the future. The resulting accounting estimates will, by definition, seldom equal the related actual results. The estimates and assumptions that have a significant risk of causing a material adjustment to the carrying amounts of assets and liabilities within the next financial year are addressed below. Going Concern When assessing going concern, the Board of Directors considers mainly the following factors: • The treasury available at the statement of financial position date; • The cash burn projected in accordance with the approved budget for next 12-month scaling-up • The availability of grant funding and outcome of ongoing and future grant applications payback loan to be received for the next 12-month • The financial facilities open to the company for raising new funds by capital increase operations. Revenue The recognition of revenue relating to license and collaboration agreements involves management estimates and requires judgement as to: (i) Classifying the license agreement (right-to-use right-to-access (ii) Identifying the performance obligations comprised in the contract; (iii) Estimating probability for (pre-)clinical (iv) Determining the agreed variable considerations to be included in the transaction price taking into account the constraining limit of the “highly probable” criteria; (v) Allocating the transaction price according to the stand-alone selling price of each of the performance obligations; and (vi) Estimating the finance component in the transaction price, based on the contract expected duration and discount rate. Management makes its judgment taking into account all information available about clinical status of the underlying projects at the reporting date and the legal analysis of each applicable contracts. Further details are contained in note 25. Recoverable Cash Advances received from the Walloon Region As explained in note 3, accounting for RCAs requires initial recognition of the fair value of the loan received to determine the benefit of the below-market rate of interest, which shall be measured as the difference between the initial carrying value of the loan and the proceeds received. Loans granted to entities in their early stages of operations, for which there is significant uncertainty about whether any income will ultimately be generated and for which any income which will be generated will not arise until a number of years in the future, normally have high interest rates. Judgment is required to determine a rate which may apply to a loan granted on an open market basis and to determine projected revenue that will derive in the future from the products that benefited from the support of the Walloon Region. The estimated projected revenue by management is similar to the ones used for impairment of non-financial In accordance with the RCA agreements, the following two components are assessed when calculating estimated future cash flows: • 30% of the initial RCA, which is repayable when the Group exploits the outcome of the research financed; and • A remaining amount, which is repayable based on a royalty percentage of future sales milestones, up to a level of 170% of the initial granted amount. After initial recognition, RCA liabilities are measured at amortized cost using the cumulative catch up method requiring management to regularly revise its estimates of payments and to adjust the carrying amount of the financial liability to reflect actual and revised estimated cash flows. Measurement and impairment of non-financial With the exception of goodwill and certain intangible assets for which an annual impairment test is required, the Group is required to conduct impairment tests where there is an indication of impairment of an asset. Measuring the fair value of non-financial Contingent consideration provisions The Group recorded a liability for the estimated fair value of contingent consideration arising from business combinations. The estimated amounts are the expected payments and timing of such payments, determined by considering the possible scenarios of forecast sales and other performance criteria, the amount to be paid under each scenario, and the probability of each scenario, which is then discounted to a net present value. The estimates could change substantially over time as new facts emerge and each scenario develops. Further details on management’s estimations and sensitivity analysis are contained in note 23. Discontinued operations In September 2022, the Group’s Manufacturing Business Unit was sold to Cellistic (see note 1). The Group does not present the expenses associated to the Manufacturing Business Unit under discontinued operations within the the consolidated statements of comprehensive income as this business unit was not considered a major line of business for the Group. In reaching this assessment, management had to apply judgment to determine if the Manufacturing Business Unit is major line of business, which included consideration of the size and role of this manufacturing unit. In the previous years, the Group focused its activities on the development of allogenic programs which decreased the manufacturing facilities requirements compared to autologous programs making the business less essential for the Group. Onerous Contract & Invoice to receive accruals As of December 31, 2022, the Group recorded a provision for onerous contracts for a total amount million in order to cover the contractual obligations, mainly on clinical activities follow-up CYAD-02, CYAD-101 CYAD-211 The Group also recognized expenses under comprehensive income statement through accruals for invoices to receive based on estimated amounts of rendered services or delivered goods during the year 2022 but not yet invoiced as per December 31, 2022 (see note 22). The Group makes these estimates based on the input from the management and communication with the vendors.

Operating segment information

Operating segment information	12 Months Ended
	Dec. 31, 2022
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Operating segment information	NOTE 6: OPERATING SEGMENT INFORMATION The chief operating decision-maker (CODM), who is responsible for making strategic decisions, allocating resources and assessing performance of the Group, has been identified as the Board of Directors. Since the acquisition of the oncological platform in 2015, the management and the CODM have determined that there are two operating segments, being: • the immuno-oncology segment regrouping all assets developed based on the CAR-T • the cardiology segment, regrouping the Cardiopoiesis platform, C-Cath ez Corporate segment includes costs for general and administration functions not allocated to the other business segments. Although the Group is currently active in Europe and in the US, no geographical financial information is currently available given the fact that the core operations are currently still in a study phase. No disaggregated information on product level or geographical level or any other level currently exists and hence also not considered by the Board of Directors for assessing performance or allocating resources. The CODM does not review assets by segments, hence no segment information per assets is disclosed. As of December 31, 2022, the main Group’s non-current Since 2017, the Group is fully focused on the development of its immuno-oncology platform. Therefore, for the year ended December 31, 2022, most of the R&D expenses were incurred in the immuno-oncology segment, in line with prior years. €‘000 For the year ended December 31, 2020 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time 5 — — 5 Revenue recognized over time — — — — Total Revenue 5 — — 5 Cost of Sales — — — — Gross Profit 5 — — 5 Research & Development expenses (124 ) (21 398 ) — (21 522 ) General & Administrative expenses — — (9 315 ) (9 315 ) Change in fair value of contingent consideration — 9 228 — 9 228 Net Other income/(expenses) (2 ) 4 582 38 4 617 Operating Profit/(Loss) (121 ) (7 589 ) (9 277 ) (16 987 ) Net financial income/(expenses) (33 ) (182 ) (3 ) (217 ) Profit/(Loss) before taxes (154 ) (7 771 ) (9 280 ) (17 204 ) Income Taxes — — — — Profit/(Loss) for the year 2020 (154 ) (7 771 ) (9 280 ) (17 204 ) €‘000 For the year ended December 31, 2021 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time — — — — Revenue recognized over time — — — — Total Revenue — — — — Cost of Sales — — — — Gross Profit — — — — Research & Development expenses (142 ) (20 631 ) — (20 773 ) General & Administrative expenses — — (9 908 ) (9 908 ) Change in fair value of contingent consideration — 847 — 847 Net Other income/(expenses) (108 ) 3 507 44 3 443 Operating Profit/(Loss) (250 ) (16 277 ) (9 864 ) (26 391 ) Net financial income/(expenses) 107 (165 ) (53 ) (111 ) Profit/(Loss) before taxes (143 ) (16 442 ) (9 917 ) (26 502 ) Income Taxes — — (10 ) (10 ) Profit/(Loss) for the year 2021 (143 ) (16 442 ) (9 927 ) (26 512 ) €‘000 For the year ended December 31, 2022 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time — — — — Revenue recognized over time — — — — Total Revenue — — — — Cost of Sales — — — — Gross Profit — — — — Research & Development expenses (587 ) (18 341 ) — (18 928 ) General & Administrative expenses — — (10 546 ) (10 546 ) Change in fair value of contingent consideration — 14 679 — 14 679 Impairment of Oncology intangible assets — (35 084 ) — (35 084 ) Net Other income/(expenses) (63 ) 9 148 (63 ) 9 022 Operating Profit/(Loss) (650 ) (29 598 ) (10 609 ) (40 857 ) Net financial income/(expenses) (19 ) (132 ) 138 (13 ) Profit/(Loss) before taxes (669 ) (29 730 ) (10 471 ) (40 870 ) Income Taxes — (65 ) — (65 ) Profit/(Loss) for the year 2022 (669 ) (29 795 ) (10 471 ) (40 935 )

Intangible assets

Intangible assets	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Intangible assets	NOTE 7: INTANGIBLE ASSETS The change in intangible assets is broken down as follows, per class of assets: (€‘000) Goodwill In-process Development Patents, Software Total Capitalized costs At January 1, 2021 883 33 678 1 084 13 071 279 48 995 Additions — — — 214 — 214 Divestiture — — — — (16 ) (16 ) At December 31, 2021 883 33 678 1 084 13 285 263 49 193 Additions — — — 876 — 876 Divestiture (239 ) — — (213 ) (165 ) (617 ) At December 31, 2022 644 33 678 1 084 13 948 98 49 452 Accumulated amortization At January 1, 2021 — — (543 ) (12 052 ) (229 ) (12 527 ) Amortization charge — — (67 ) (134 ) (16 ) (217 ) Divestiture — — — — 16 16 At December 31, 2021 — — (610 ) (12 186 ) (229 ) (13 025 ) Amortization charge — — (66 ) (547 ) — (613 ) Divestiture — — — 3 131 134 Impairment (644 ) (33 678 ) — (762 ) — (35 084 ) At December 31, 2022 (644 ) (33 678 ) (676 ) (13 492 ) (98 ) (48 588 ) Net book value Capitalized costs 883 33 678 1 084 13 285 263 49 193 Accumulated amortization — — (610 ) (12 186 ) (229 ) (13 025 ) At December 31, 2021 883 33 678 474 1 099 34 36 168 Capitalized costs 644 33 678 1 084 13 948 98 49 452 Accumulated amortization (644 ) (33 678 ) (676 ) (13 492 ) (98 ) (48 588 ) At December 31, 2022 — — 408 456 — 864 Goodwill and IPR&D resulted from the purchase price allocation exercise performed for the acquisition of Oncyte LLC in 2015. As of December 31, 2022, and 2021, Goodwill and IPR&D are not amortized but tested for impairment. The capitalized development costs relate to the development of C-Cathez. C-Cathez (C-Cure, CYAD-01, CYAD-02, CYAD-101, CYAD-211…) 3 t Patents, licenses and trademarks, mainly relate to the following items: • Exclusive Agreement for Horizon Discovery’s shRNA Platform to develop next-generation allogenic CAR T Therapies acquired for €0.9 million at the end of December 2018. Since acquisition, the Company capitalized milestone payments for a total amount o f is being ; • An intangible asset has been capitalized in January 2022 for $1.0 million (€0.9 million), reflecting the Group’s opportunity to explore new partnership for the C-Cathez, which is being amortized over a period (see note 5.8); and • During the course of 2022, two exclusive licenses agreements have been terminated resulting in disposal of € 0. 3 Impairment testing Impairment testing is detailed below. Immuno-oncology CGU impairment test 3 Goodwill and IPR&D exclusively relate to the acquisition of the former entity Oncyte LLC (meanwhile liquidated into Celyad SA) which was acquired in 2015. Management performs an annual impairment test on goodwill and on ‘indefinite lived assets’ that are not amortized in accordance with the accounting policies stated in note 3. The impairment test has been performed at the level of the immuno-oncology segment corresponding to the CGU to which the goodwill and the IPR&D belong as well as the Horizon Discovery’s shRNA platform. The recoverable amount associated to this CGU is calculated based on the fair value less costs to sell model using Level 3 fair value measurements for which the Group developed unobservable inputs and requires the use of assumptions. In October 2022, the Group announced its new business strategy “Celyad 2.0” (see note 1), under which the Company has decided to discontinue the development of its remaining clinical programs, shifting from an organization focused on clinical development to one prioritizing R&D discovery and the monetization of its IP portfolio through partnerships, collaborations and license agreements. Therefore, the cash flow projections based on the previous business plan became obsolete. 3 The uncertainly raised by the COVID-19 COVID-19 Consequently, as of December 31, 2022, Management built a T-cell The accounting standard IAS 38 impose that projected future cash inflow of economic benefits used for the valuation of a recoverable amount associated to a CGU cannot be remote. Due to the early stage of the implementation of the Celyad 2.0 strategy and the fact no firm sublicence contract nor collaboration contract was concluded as of December 31, 2022, Management had to recognize that significant uncertainty exist on the timing and amount of the new strategy outcomes and therefore had to conclude that the possibility of any inflow, as of December 31, 2022, was remote regarding accounting standards definition. Therefore, Management recognized a full impairment loss on the remaining value of the goodwill, IPR&D and Horizon Discovery’s shRNA platform. This accounting conclusion, which reflects a picture of the situation at December 31, 2022, does not affect Management’s commitment to continue the exploitation of these IPs in its new Celyad 2.0 strategy. As soon as a future event (such as a firm sublicense or collaboration contract) will increase the probability of revenue, indicating that the probability is more than remote and consequently that the recognized impairment losses may no longer exist or may have decreased, the Group will estimate the cash-generating unit’s recoverable amount.. The reversal will be limited so that the carrying amount of the asset does not exceed its recoverable amount. An impairment loss recognized on goodwill is however not reversed in a subsequent period. For comparative purpose, as of December 31, 2021, the calculations used cash flow projections based on a business plan ending in 2040 based on probability of success of CYAD-02, CYAD-101 and CYAD-211 product candidates as well as extrapolations of projected cash flows resulting from the future expected sales on CYAD-101 and CYAD-211 and sublicense income associated with CYAD-02. The CGU’s recoverable value, determined accordingly, exceeded its carrying amount. Accordingly, no impairment loss was recognized either on goodwill, IPR&D, the Horizon Discovery’s shRNA platform or other immuno-oncology licenses at December 31, 2021. As of December 31, 2021, Management’s key assumptions (assumptions to which the unit’s or group of units’, recoverable amount is most sensitive) about projected cash flows when determining fair value less costs to sell were as follows: • Discount rate (WACC) Management had estimated the discount rate (WACC) as of December 31, 2021, to be 13.4% based on following components: the US Government Treasury bill 20-Y, was • Projected Revenue Management had estimated the projected revenue (using cash flow projections ending in 2040) based on the following components: total market and market share, time-to-market, • Probabilities of Success (PoS) Management had estimated the PoS based on Clinical Development Success Rates observed by independent business intelligence consulting companies for hematological and solid tumor diseases. Probability of the Group’s product candidates reaching the market used had been updated compared to prior year-end PoS Phase I Phase I to Phase Phase II to Phase Phase III to BLA BLA to Approval Cumulative PoS CYAD-02 100 % 50 % 28 % 60 % 90 % 7.5 % CYAD-101 100 % 49 % 23 % 43 % 93 % 4.6 % CYAD-211 100 % 50 % 28 % 60 % 90 % 7.5 %

Property, plant and equipment

Property, plant and equipment	12 Months Ended
	Dec. 31, 2022
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Property, plant and equipment	NOTE 8: PROPERTY, PLANT AND EQUIPMENT (€’000) Property Equipment Furniture Leasehold Total Capitalized costs At January 1, 2021 3 001 3 563 250 4 032 10 846 Additions 24 388 — 10 422 Disposals — (192 ) — — (192 ) Currency translation adjustments — 1 — 15 16 At December 31, 2021 3 025 3 760 250 4 057 11 092 Additions 146 116 15 — 277 Disposals (3 171 ) (2 180 ) (45 ) (2 903 ) (8 299 ) Currency translation adjustments — 1 — 11 12 Transfers to Assets held for sale — (421 ) (220 ) (989 ) (1 630 ) At December 31, 2022 — 1 276 — 176 1 452 Accumulated depreciation: At January 1, 2021 (827 ) (2 625 ) (214 ) (3 061 ) (6 727 ) Depreciation charge (454 ) (512 ) (24 ) (313 ) (1 303 ) Disposals — 191 — — 191 Currency translation adjustments — (2 ) — (3 ) (5 ) At December 31, 2021 (1 281 ) (2 948 ) (238 ) (3 377 ) (7 844 ) Depreciation charge (439 ) (268 ) — (120 ) (827 ) Disposals 1 720 1 834 18 2 575 6 147 Currency translation adjustments — — — (5 ) (5 ) Transfers to Assets held for sale — 414 220 751 1 385 At December 31, 2022 — (968 ) — (176 ) (1 144 ) Net book value Capitalized costs 3 025 3 760 250 4 057 11 092 Accumulated depreciation (1 281 ) (2 948 ) (238 ) (3 377 ) (7 844 ) At December 31, 2021 1 744 812 12 680 3 248 Capitalized costs — 1 276 — 176 1 452 Accumulated depreciation — (968 ) — (176 ) (1 144 ) At December 31, 2022 — 309 — — 309 Property, Plant and Equipment is mainly composed of right-of-use In September 2022, the six-year In September 2022, the Company’s Manufacturing Business Unit based in Belin 12 building in Mont-Saint-Guibert, Belgium, was sold to Cellistic for a total consideration of €6.0 million (see note 5.1). The Manufacturing Business Unit included facilities and equipment, office furniture, leasehold improvements, and laboratory equipment. The book value of assets sold was approximately €0.8 million (including related goodwill). Consequent to the sale of the Manufacturing Business Unit, the lease on the related offices was terminated, resulting in the write-off of the right-of-use asset and related capitalized assets of approximately €0.6 million and €0.9 million, respectively.

Inventories and Work in Progres

Inventories and Work in Progress	12 Months Ended
	Dec. 31, 2022
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Inventories and Work in Progress	NOTE 10: INVENTORIES AND WORK IN PROGRESS Not applicable.

Trade, Other Receivables and Ot

Trade, Other Receivables and Other assets	12 Months Ended
	Dec. 31, 2022
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Trade, Other Receivables and Other assets	NOTE 11: TRADE, OTHER RECEIVABLES AND OTHER ASSETS (€‘000) As at December 31, 2022 2021 Trade receivables 909 203 Advance deposits 209 246 Net Investment in Lease — 219 Total Trade and Other receivables 1 118 668 Current Grant receivables (RCAs) — 1 121 Current Grant receivables (Others) — 274 Total Current Grant receivables — 1 395 Prepaid expenses 667 1 688 VAT receivable 316 483 Income and other tax receivables 34 40 Total Other current assets 1 017 2 211 Total Trade receivables, advances and other current assets 2 135 4 274 The increase of trade receivables is mainly due to credit notes to be received following the closing of clinical studies for an amount of 0.3 million and an amount of € 0.2 million related to the sales of the C-Cathez, At December 31, 2021, the current net investment in lease related to the receivable recorded under subleases. The lease has ended in September 2022, such as the balance as of December 31, 2022 is equal to zero. As of December 31, 2022, all grant receivables from the Walloon Region have been paid. The decrease in other current assets as of December 31, 2022 compared to December 31, 2021 of million is mainly driven by the timing of payments on insurances contracts and buildings rents combined with the reversal of transaction costs for an amount million mainly linked to the LPC equity facility not subject to further capitalization and not available to be offset against a future capital raise as the equity facility expired early January 2023. In addition, the VAT receivable decreased along with clinical expenses as a result of decreased clinical activities at year-end.

Short-Term Investments

Short-Term Investments	12 Months Ended
	Dec. 31, 2022
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Short-Term Investments	NOTE 12: SHORT-TERM INVESTMENT Given the level of market interest rates for corporate deposits of short-term maturities, the Group has not invested in short-term deposits over the years 2022 and 2021.

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2022
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Cash and Cash Equivalents	NOTE 13: CASH AND CASH EQUIVALENTS (€‘000) As at December 31, 2022 2021 Cash at bank and on hand 12 445 30 018 Total 12 445 30 018 The Group’s cash and cash equivalents amounted to €12.4 million at December 31, 2022 which accounts for a decrease of €17.6 million as compared to year-end Cash at banks earn interest at floating rates based on daily bank deposit rates. For the years ended December 31, 2022 and 2021, the earned bank interests have been insignificant.

Investment in Subsidiaries

Investment in Subsidiaries	12 Months Ended
	Dec. 31, 2022
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Investment in Subsidiaries	NOTE 14: INVESTMENT IN SUBSIDIARIES The consolidation scope of the Group is as follows, for both current and comparative years presented in these year-end Name Country of Nature of Proportion of shares directly held by parent Proportion of Proportion of non-controlling Celyad SA BE Biopharma Parent company Celyad Inc US Biopharma 100 % 100 % 0 % CorQuest Medical Inc US Medical Device 100 % 100 % 0 % Biological Manufacturing Services SA BE Manufacturing 100 % 100 % 0 %

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2022
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Share Capital	NOTE 15: SHARE CAPITAL The number of shares issued is expressed in units. As at December 31, 2022 2021 Total number of issued and outstanding shares 22 593 956 22 593 956 Total share capital (€‘000) 78 585 78 585 As of December 31, 2022 and 2021, the share capital amounted , paid-up non-employees As of December 31, 2022, total number of authorized shares remains available for issuance are 1,361,242, out of which, 323,700 number of shares are reserved under share based compensation plan. History of the capital of the Company The Company was incorporated on July 24, 2007 with a share capital of €62,500 by the issuance of 409,375 class A shares. On August 31, 2007, the Company has issued 261,732 class A shares to Mayo Clinic by way of a contribution in kind of the upfront fee that was due upon execution of the Mayo License for a total amount of €9,500,000. Round B Investors participated in a capital increase of the Company by way of a contribution in kind of a convertible loan (€2,387,049) and a contribution in cash (€4,849,624 of which €1,949,624 was uncalled) on December 23, 2008; 204,652 class B shares were issued at the occasion of that capital increase. Since then, the capital is divided in 875,759 shares, of which 671,107 are class A shares and 204,652 are class B shares. On October 29, 2010, the Company closed its third financing round resulting in a capital increase totaling €12,100,809. The capital increase can be detailed as follows: • capital increase in cash by certain existing investors for a total amount of €2,609,320.48 by the issuance of 73,793 class B shares at a price of €35.36 per share; • capital increase in cash by certain existing investors for a total amount of €471,240 by the issuance of 21,000 class B shares at a price of €22.44 per share; • capital increase in cash by certain new investors for a total amount of €399,921.60 by the issuance of 9,048 class B shares at a price of €44.20 per share; • exercise of 12,300 warrants (“Warrants A”) granted to the Round C investors with total proceeds of €276,012 and issuance of 12,300 class B shares. The exercise price was €22.44 per Warrant A; • contribution in kind by means of conversion of the loan C for a total amount of €3,255,524.48 (accrued interest included) by the issuance of 92,068 class B shares at a conversion price of €35.36 per • contribution in kind by means of conversion of the loan D for a total amount of €2,018,879.20 (accrued interest included) by the issuance of 57,095 class B shares at a conversion price of €35.36 per share. The loan D is a convertible loan granted by certain investors to the Company on 14 October 2010 for a nominal amount of €2,010,000. • contribution in kind of a payable towards Mayo Foundation for Medical Education and Research for a total amount of €3,069,911 by the issuance of 69,455 class B shares at a price of €44.20 per share. The payable towards Mayo Clinic was related to (i) research undertaken by Mayo Clinic in the years 2009 and 2010, (ii) delivery of certain materials, (iii) expansion of the Mayo Clinical Technology License Contract by way the Second Amendment dated October 18, 2010. On May 5, 2011, pursuant the decision of the Extraordinary General Meeting, the capital was reduced by an amount of €18,925,474 equivalent to the outstanding net loss as of December 31, 2010. On May 31, 2013, the Company closed its fourth financing round, the ‘Round D financing’. The convertible loans E, F, G and H previously recorded as financial debt were converted in shares which led to an increase in equity for a total amount of €28,645k of which €5,026k is accounted for as capital and € 6,988k as share premium. The remainder (€ 16,631k) is accounted for as other reserves on fully settled contribution in kind convertible loans. Furthermore, a contribution in cash by existing shareholders of the Company led to an increase in share capital and issue premium by an amount of €7,000k. At the Extraordinary Shareholders Meeting of June 11, 2013 all existing classes of shares of the Company have been converted into ordinary shares. Preferred shares have been converted at a 1 for 1 ratio. On July 5, 2013, the Company completed its Initial Public Offering. The Company issued 1,381,500 new shares at €16.65 per shares, corresponding to a total of €23,002k. On July 15, 2013, the over-allotment option was fully exercised for a total amount of €3,450k corresponding to 207,225 new shares. The total IPO proceeds amounted to €26,452k and the capital and the share premium of the Company increased accordingly. The costs relating to the capital increases performed in 2013 amounted to €2.8 million and are presented as a deduction of share premium. On June 11, 2013, the Extraordinary General Shareholders’ Meeting of Celyad SA authorized the Board of Directors to increase the share capital of the Company, in one or several times, and under certain conditions set forth in extenso in the articles of association. This authorization is valid for a period of five years starting on July 26, 2013 and until July 26, 2018. The Board of Directors may increase the share capital of the Company within the framework of the authorized capital for an amount of up to €21,413k. Over the course of 2014, the capital of the Company was increased in June 2014 by way of a capital increase of €25,000k represented by 568,180 new shares fully subscribed by Medisun International Limited. In 2014, the capital of the Company was also increased by way of exercise of Company warrants. Over four different exercise periods, 139,415 warrants were exercised resulting in the issuance of 139,415 new shares. The capital and the share premium of the Company were therefore increased respectively by €488k and €500k. In January 2015, the shares of Oncyte LLC were contributed to the capital of the Company, resulting in a capital increase of €3,452k and the issuance of 93,087 new shares. In 2015, the Company conducted two fund raisings. A private placement was closed in March resulting in a capital increase of €31,745k represented by 713,380 new shares. The Company also completed an IPO on Nasdaq in June, resulting in a capital increase of €87,965k represented by 1,460,000 new shares. Also, in 2015, the capital of the Company was also increased by way of exercise of Company warrants. Over three different exercise periods, 6,749 warrants were exercised resulting in the issuance of 6,749 new shares. The capital and the share premium of the Company were therefore increased respectively by €23k and €196k. Over 2017 the capital of the Company was also increased by way of exercise of Company warrants. Over four different exercise periods, 225,966 warrants were exercised resulting in the issuance of 225,966 new shares. The capital of the Company was therefore increased by €625k. In August 2017, pursuant to the amendment of the agreements with Celdara Medical LLC and Dartmouth College, the CAR T technology inventors, the capital of the Company was increased by way of contribution in kind of a liability owed to Celdara Medical LLC. 328,275 new shares were issued at a price of €32.35 (being Celyad share’s average market price for the 30 days preceding the transaction) and the capital and the share premium of the Company were therefore increased respectively by €1,141k and €9,479k without an impact on the cash and cash equivalents, explaining why such transaction is not disclosed in the consolidated statements of cash In May 2018, the Company completed a global offering of $54.4 million (€46.1 million), resulting in cash proceeds for an amount of €43.0 million net of bank fees and transaction costs. In May 2019, share premium decreased as a result of the absorption of accounting losses for an amount of €172.3 million, with a counterpart in the financial statements line item ‘Accumulated Deficit’. The absorption of the accumulated deficit into share premium is a non-cash In September 2019, the Company completed a global offering of $20.0 million (€18.2 million), resulting in cash proceeds for an amount of €16.4 million net of bank fees and transaction costs. On January 8, 2021, the Company has entered into a committed equity purchase agreement (“Purchase Agreement”) for up to $40.0 million with Lincoln Park Capital Fund, LLC (“LPC”), a Chicago-based institutional investor. Over the 24-month million. As of December 31, 2022, there was a remaining access to the Purchase Agreement established with LPC for an amount of $ million. The Purchase Agreement expired early January 2023. During the extraordinary shareholders meeting of May, 25 2021, the shareholders, in accordance with Belgian Company Law, approved the absorption of approximately €43.3 million of accounting losses into share premium. As a result, share premium has been reduced by a cumulative amount of €43.3 million in the 12 months period ended December 31, 2021 (€234.6 million of loss absorption has been approved and recorded from inception to December 31, 2022, as no such loss absorption occurred in 2022) against capital reduction reserve. This transaction has no impact on the total equity, comprehensive income (loss), assets (including cash) nor liabilities. On May, 21 2021 and June 14, 2021, a total of 188,800 new shares have been issued by the Company and subscribed by Jefferies under the AT On December 8, 2021, 6,500,000 new shares were issued by decision of the board of directors and subscribed for by CFIP CLYD LLC in the framework of a private placement for a global cash proceed of €28.9 million. As of December 31, 2022, all shares issued have been fully paid. The following share issuances occurred since the incorporation of the Company: Category Transaction date Description # of shares Par Class A shares 24 July 2007 Company incorporation 409 375 0.15 Class A shares 31 August 2007 Contribution in kind (upfront fee Mayo License) 261 732 36.30 Class B shares 23 December 2008 Capital increase (Round B) 137 150 35.36 Class B shares 23 December 2008 Contribution in kind (Loan B) 67 502 35.36 Class B shares 28 October 2010 Contribution in cash 21 000 22.44 Class B shares 28 October 2010 Contribution in kind (Loan C) 92 068 35.36 Class B shares 28 October 2010 Contribution in kind (Loan D) 57 095 35.36 Class B shares 28 October 2010 Contribution in cash 73 793 35.36 Class B shares 28 October 2010 Exercise of warrants 12 300 22.44 Class B shares 28 October 2010 Contribution in kind (Mayo receivable) 69 455 44.20 Class B shares 28 October 2010 Contribution in cash 9 048 44.20 Class B shares 31 May 2013 Contribution in kind (Loan E) 118 365 38.39 Class B shares 31 May 2013 Contribution in kind (Loan F) 56 936 38.39 Class B shares 31 May 2013 Contribution in kind (Loan G) 654 301 4.52 Class B shares 31 May 2013 Contribution in kind (Loan H) 75 755 30.71 Class B shares 31 May 2013 Contribution in cash 219 016 31.96 Class B shares 4 June 2013 Conversion of warrants 2 409 176 0.01 Ordinary shares 11 June 2013 Conversion of Class A and Class B shares in ordinary shares 4 744 067 — Ordinary shares 5 July 2013 Initial Public Offering 1 381 500 16.65 Ordinary shares 15 July 2013 Exercise of over-allotment option 207 225 16.65 Ordinary shares 31 January 2014 Exercise of warrants issued in September 2008 5 966 22.44 Ordinary shares 31 January 2014 Exercise of warrants issued in May 2010 333 22.44 Ordinary shares 31 January 2014 Exercise of warrants issued in January 2013 120 000 4.52 Ordinary shares 30 April 2014 Exercise of warrants issued in September 2008 2 366 22.44 Ordinary shares 16 June 2014 Capital increase 284 090 44.00 Ordinary shares 30 June 2014 Capital increase 284 090 44.00 Ordinary shares 4 August 2014 Exercise of warrants issued in September 2008 5 000 22.44 Ordinary shares 4 August 2014 Exercise of warrants issued in October 2010 750 35.36 Ordinary shares 3 November 2014 Exercise of warrants issued in September 2008 5 000 22.44 Ordinary shares 21 January 2015 Contribution in kind (Celdara Medical LLC) 93 087 37.08 Ordinary shares 7 February 2015 Exercise of warrant issued in May 2010 333 22.44 Ordinary shares 3 March 2015 Capital increase 713 380 44.50 Ordinary shares 11 May 2015 Exercise of warrant issued in May 2010 500 22.44 Ordinary shares 24 June 2015 Capital increase 1 460 000 60.25 Ordinary shares 4 August 2015 Exercise of warrant issued in May 2010 666 22.44 Ordinary shares 4 August 2015 Exercise of warrant issued in October 2010 5 250 35.36 Ordinary shares 1 February 2017 Exercise of warrant issued in May 2013 207 250 2.64 Ordinary shares 2 May 2017 Exercise of warrant issued in May 2013 4 900 2.64 Ordinary shares 1 August 2017 Exercise of warrant issued in May 2013 7 950 2.64 Ordinary shares 23 August 2017 Contribution in kind (Celdara Medical LLC) 328 275 32.35 Ordinary shares 9 November 2017 Exercise of warrant issued in May 2013 5 000 2.64 Ordinary shares 9 November 2017 Exercise of warrant issued in October 2010 866 35.36 Ordinary shares 7 February 2018 Exercise of warrant issued in May 2013 4 500 2.64 Ordinary shares 22 May 2018 Capital increase 2 070 000 22.29 Ordinary shares 16 September 2019 Capital increase 2 000 000 9.08 Ordinary shares 8 January 2021 Capital increase 262 812 4.94 Ordinary shares 29 March 2021 Capital increase 200 000 6.19 Ordinary shares 9 April 2021 Capital increase 300 000 5.83 Ordinary shares 29 April 2021 Capital increase 300 000 5.23 Ordinary shares 21 May 2021 Capital increase 182 000 4.58 Ordinary shares 14 June 2021 Capital increase 6 800 4.98 Ordinary shares 28 June 2021 Capital increase 300 000 4.46 Ordinary shares 22 July 2021 Capital increase 300 000 3.46 Ordinary shares 20 October 2021 Capital increase 300 000 3.38 Ordinary shares 8 December 2021 Capital increase 6 500 000 4.44 (€000) Nature of the transactions Share Share Capital Other Accumulated Number of Balance as at January 1, 2021 48 513 43 349 191 213 30 958 (283 039 ) 13 942 344 Reduction of share premium by absorption of losses — (43 349 ) 43 349 — — — Capital increase 30 072 8 900 — — — 8 651 612 Transaction costs associated with capital increases — (2 583 ) — — — — Loss for the period — — — — (26 512 ) — Share Based Payment — — — 2 172 — — Currency Translation differences — — — 42 — — Remeasurements of defined benefit obligation — — — — 554 — Balance as at December 31, 2021 78 585 6 317 234 562 33 172 (308 997 ) 22 593 956 Loss for the period — — — — (40 935 ) — Share Based Payment — — — 1 624 — — Currency Translation differences — — — 4 — — Remeasurements of defined benefit obligation — — — — (15 ) — Balance as at December 31, 2022 78 585 6 317 234 562 34 800 (349 947 ) 22 593 956 The total number of shares issued and outstanding as of December 31, 2022, totals 22,593,956 ordinary common shares. Capital reduction reserve Pursuant to Belgian Companies and Associations Code, the calculation of amounts available for distribution to shareholders, as dividends or otherwise, must be determined on the basis of our standalone non-consolidated non-amortized non-amortized paid-up non-distributable non-consolidated In addition to the above test, the Company must also meet a liquidity test in order to be able to declare and/or distribute dividends. During the extraordinary shareholders meeting of May 25, 2021, the shareholders, in accordance with Belgian Companies and Associations Code, approved the absorption of approximately €43.3 million of accounting losses into share premium. As a result, share premium had been reduced by a cumulative amount of €43.3 million in the 12 months period ended December 31, 2021 (€234.6 million of loss absorption has been approved and recorded from inception to December 31, 2022, as no such loss absorption occurred in 2022) against capital reduction reserve. This transaction has no impact on the total equity, comprehensive income (loss), assets (including cash) nor liabilities.

Share-Based Payments

Share-Based Payments	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Share-Based Payments	NOTE 16: SHARE-BASED PAYMENTS The Group operates an equity-based compensation plan, whereby warrants are granted to directors, management and selected employees and non-employees. obligation Each warrant gives the beneficiaries the right to subscribe to one common share of the Group. The warrants are granted for free and have an exercise price equal to the lower of the average closing price of the Group’s share over the 30 days prior to the offer, and the last closing price before the day of the offer, as determined by the Board of Directors of the Group. Changes in the number of warrants outstanding and their related weighted average exercise prices are as follows: 2022 2021 Weighted average Number of warrants Weighted average Number of warrants Outstanding as of January 1, 13.06 2 136 556 17.00 1 488 006 Granted 1.82 594 450 5.29 760 800 Forfeited 2.74 (109 108 ) 4.94 (77 250 ) Exercised — — — — Expired 15.80 (282 252 ) 10.23 (35 000 ) At December 31, 8.36 2 339 646 13.06 2 136 556 Warrants outstanding at the end of the year have the following expiry date and exercise price: Warrant plan issuance date Vesting date Expiry date Number of warrants Number of warrants Exercise 06 May 2013 06 May 2016 06 May 2023 2 500 2 500 2.64 05 May 2014 05 May 2017 05 May 2024 35 698 35 698 38.25 05 November 2015 05 November 2018 05 November 2025 79 315 79 315 30.67 08 December 2016 08 December 2019 08 December 2021 7 500 7 500 32.04 29 June 2017 29 June 2020 31 July 2022 — 282 251 31.34 26 October 2018 26 October 2021 31 December 2023 365 817 365 817 18.26 25 October 2019 25 October 2022 31 December 2024 529 950 549 842 7.13 11 December 2020 10 December 2023 31 December 2027 498 883 532 133 6.24 11 October 2021 11 October 2024 31 December 2028 819 983 281 500 2.38 2 339 646 2 136 556 The Group has a reserve of 568,500 authorized warrants for share based compensation plan as of December 31, 2022. Warrants issued on May 6, 2013 At the Extraordinary Shareholders Meeting of May 6, 2013, a plan of 266,241 warrants was approved. Warrants were offered to Group’s employees and management team. Out of the 266,241 warrants offered, 253,150 warrants were accepted by the beneficiaries and 2,500 warrants are outstanding as of December 31, 2022. The 253,150 warrants were vested in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary the issuance. The warrants that are vested can only be exercised at the end of the third calendar year following the issuance date, thus starting on January 1, 2017. The exercise price amounts to €2.64. Warrants not exercised within 10 years after issue become null and void. Warrants issued on May 5, 2014 At the Extraordinary Shareholders Meeting of May 5, 2014, a plan of 100,000 warrants was approved. Warrants were offered to Group’s employees, non-employees The 100,000 warrants were vested in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary the issuance. The warrants that are vested can only be exercised at the end of the third calendar year following the issuance date, thus starting on January 1, 2018. The exercise price of the different tranches ranges from €33.49 to €45.05. Warrants not exercised within 10 years after issue become null and void. Warrants issued on 5 November 2015 At the Extraordinary Shareholders Meeting of 5 November 2015, a plan of 466,000 warrants was approved. Warrants were offered to Group’s employees, non-employees These warrants vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2019. The exercise price of the different tranches ranges from €15.90 to €34.65. Warrants not exercised within 10 years after issue become null and void. Warrants issued on December 8, 2016 On December 8, 2016, the Board of Directors issued a new plan of 100,000 warrants. An equivalent number of warrants were cancelled from the remaining pool of warrants of the plan of November 5, 2015. Warrants were offered to Group’s employees and non-employees These warrants will vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2020. The exercise price of the different tranches ranges from €17.60 to €36.81. Warrants not exercised within 5 years after issue become null and void. Warrants issued on June 29, 2017 At the Extraordinary Shareholders Meeting of June 29, 2017, a plan of 520,000 warrants was approved. Warrants were offered in different tranches to beneficiaries (employees, non-employees outstanding as of December 31, 2022, as they have expired in 2022. These warrants will be vested in equal tranches over a period of three Warrants issued on October 26, 2018 On October 26, 2018, the Board of Directors issued a new plan of 700,000 warrants. Warrants were offered in different tranches to beneficiaries (employees, non-employees These warrants will vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2022. The exercise price of the different tranches ranges from €9.36 to €22.04. Warrants not exercised within 5 years after issue become null and void after the 31st of December of the 5 th Warrants issued on October 25, 2019 On October 25, 2019, the Board of Directors issued a new plan of 939,500 warrants. Warrants were offered in different tranches to beneficiaries (employees, non-employees These warrants will vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2023. The exercise price of the different tranches ranges from €5.97 to €9.84. Warrants not exercised within 5 years after issue become null and void after the 31st of December of the 5 th Warrants issued on December 11, 2020 On December 11, 2020, the Board of Directors issued a new plan of 561,525 warrants. Warrants were offered in different tranches to beneficiaries (employees, non-employees These warrants will vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2024. The exercise price of the different tranches ranges from €3.72 to €6.81. Warrants not exercised within 7 years after issue become null and void after the 31st of December of the 7 th Warrants issued on October 11, 2021 On October 11, 2021, the Board of Directors issued a new plan of 777,050 warrants. Warrants were offered in different tranches to beneficiaries (employees, non-employees These warrants will vest in equal tranches over a period of three years. The warrants become 100% vested after the third anniversary of issuance. The warrants that are vested can only be exercised as from the end of the third calendar year following the issuance date, thus starting on January 1, 2025. The exercise price of the different tranches ranges from €1.64 to €3.75. Warrants not exercised within 7 years after issue become null and void after the 31st of December of the 7 th Warrants issued on October 5, 2022 On October 5, 2022, the Board of Directors issued a new plan of 323,700 warrants. Warrants were offered in different tranches to beneficiaries (employees, non-employees As a result, as of December 31, 2022 , The fair value of the warrants has been determined at grant date based Warrants issued on 06 May 05 May 05 Nov. 08 Dec. 29 Jun. 26 Oct. 25 Oct. 10 Dec. 11 Oct. Total Number of warrants issued 266 241 100 000 466 000 100 000 520 000 700 000 939 500 561 525 777 050 4 430 316 Number of warrants accepted 253 150 94 400 353 550 45 000 334 400 426 050 602 025 557 050 874 200 3 539 825 Number of warrants not fully — — — — — — 289 834 498 883 819 983 1 608 700 Average exercise price (in €) 2.64 38.25 30.67 32.04 31.34 18.26 7.13 6.24 2.38 Expected share value 39.55 % 67.73 % 60.53 % 61.03 % 60.61 % 58.82 % 59.14 % 58.84 % 56.86 % Risk-free interest rate 2.06 % 1.09 % 0.26 % -0.40 % -0.23 % -0.06 % -0.38 % -0.66 % -0.30 % Average fair value (in €) 12.44 25.19 20.04 16.18 15.58 8.90 3.99 3.45 1.36 Weighted average remaining 0.34 1.34 2.84 (1.07 ) (0.51 ) 0.82 1.81 4.94 5.78

Post-Employment Benefits

Post-Employment Benefits	12 Months Ended
	Dec. 31, 2022
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Post-Employment Benefits	NOTE 17: POST-EMPLOYMENT BENEFITS (€’000) As at December 31, 2022 2021 Pension obligations 13 53 Total 13 53 The Group operates a pension plan which requires contributions to be made by the Group to an insurance company. The pension plan is a defined contribution plan. However, because of the Belgian legislation applicable to 2nd pillar pension plans (so-called At the end of each year, the Group is measuring and accounting for the potential impact of defined benefit accounting for these pension plans with a minimum fixed guaranteed return. The contributions to the plan are determined as a percentage of the yearly salary. There are no employee contributions. The benefit also includes a death in service benefit. The amounts recognized in the statement of financial position are determined as follows: (€‘000) As at December 31, 2022 2021 Present value of funded obligations 2 568 2 408 Fair value of plan assets (2 555 ) (2 355 ) Deficit of funded plans 13 53 Total deficit of defined benefit pension plans 13 53 Liability in the statement of financial position 13 53 The change in the defined benefit liability over the year is as (€‘000) Present value Fair value of Total At January 1, 2021 2 747 2 133 614 Current service cost 206 — 206 Interest expense/(income) 18 49 (31 ) 2 971 2 182 789 Remeasurements - Actuarial (Gain)/loss due to change in actuarial assumptions (17 ) — (17 ) - Actuarial (Gain)/loss due to change in demographic assumptions 36 — 36 - Actuarial (Gain)/Loss due to experience (537 ) — (537 ) (518 ) — (518 ) Employer contributions: — 218 (218 ) Benefits Paid (45 ) (45 ) — At December 31, 2021 2 408 2 355 53 At January 1, 2022 2 408 2 355 53 Current service cost 169 — 169 Interest expense/(income) 26 23 3 2 603 2 378 225 Remeasurements - Actuarial (Gain)/loss due to change in actuarial assumptions (13 ) — (13 ) - Actuarial (Gain)/Loss due to experience 26 — 26 - Curtailment in year (3 ) — (3 ) 10 — 10 Employer contributions: — 222 (222 ) Benefits Paid (45 ) (45 ) — At December 31, 2022 2 568 2 555 13 The plan assets are 100% invested in an insurance product. The income statement charge included in operating profit for post-employment benefits amount to: (€‘000) 2022 2021 2020 Current service cost 169 206 233 Interest expense on DBO 26 18 30 Expected return on plan assets (24 ) (13 ) (24 ) Amount recognized on curtailment/settlement (3 ) — — Net periodic pension cost 168 211 239 The re-measurements (€‘000) 2022 2021 2020 Effect of changes in actuarial assumptions (13 ) (17 ) 187 Effect of experience adjustments 26 (537 ) 24 Effect of changes in demographic assumptions — 36 — (Gain)/Loss on assets for the year 2 (36 ) (14 ) Remeasurement of post-employment benefit obligations 15 (554 ) 197 Plan assets relate all to qualifying insurance policies. The significant actuarial assumptions as per December 31, 2022 were as follows: Demographic assumptions (for both current and comparative years presented in these year-end • Mortality tables: mortality rates-5 • Withdrawal rate: 13.5% for age <55, 0.0% for age ≥55 (no change compared to comparative period) • Retirement age: 65 years Economic assumptions: • Yearly inflation rate: 2.2% (vs 2.0% compared to comparative period) • Yearly salary raise: 1.5% (above inflation), no change compared to comparative period • Yearly discount rate: 3.8% (vs 1.0% last year). The discount rate reflects the yield on high quality (AA) long-term corporate bonds (within the EURO zone) having the same duration as the duration of the pension liabilities at the valuation date. If the discount rate would decrease by 0.5% then, the defined benefit obligation would increase by 0.00%. If the discount rate would increase by 0.5% then the defined benefit obligation would decrease by 0.00%. The above sensitivity analysis is based on a change in an assumption while holding all other assumptions constant. In practice, this is unlikely to occur, and changes in some of the assumptions may be correlated. When calculating the sensitivity of the defined benefit obligation to significant actuarial assumptions the same method (present value of the defined benefit obligation calculated with the projected unit credit method at the end of the reporting period) has been applied as when calculating the pension liability recognized within the statement of financial position. Through its defined benefit pension plan, the Group is exposed to several risks, the most significant of which are detailed below: • Changes in discount rate: a decrease in discount rate will increase plan liabilities; • Inflation risk: the pension obligations are linked to inflation, and higher inflation will lead to higher liabilities. The majority of the plan’s assets are either unaffected by or loosely correlated with inflation, meaning that an increase in inflation will also increase the deficit. The investment positions are managed by the insurance company within an asset-liability matching framework that has been developed to achieve long-term investments that are in line with the obligations under the pension schemes. Expected contributions to pension plans for next financial year amount to €0.2 million.

Other Reserves

Other Reserves	12 Months Ended
	Dec. 31, 2022
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Other Reserves	NOTE 18: OTHER RESERVES (€’000 ) Share based Other equity Currency Total Balance as at January 1, 2021 15 803 16 631 (1 476 ) 30 958 Vested share-based payments 2 172 — — 2 172 Currency Translation differences subsidiaries — — 42 42 Balance as at December 31, 2021 17 975 16 631 (1 434 ) 33 172 Vested share-based payments 1 624 — — 1 624 Currency Translation differences subsidiaries — — 4 4 Balance as at December 31, 2022 19 599 16 631 (1 430 ) 34 800 The amount of €16.6 million has been accounted for as other reserves following the conversion of contribution-in-kind

Recoverable Cash Advances

Recoverable Cash Advances	12 Months Ended
	Dec. 31, 2022
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Recoverable Cash Advances	NOTE 19: RECOVERABLE CASH ADVANCES (€‘000) As at December 31, 2022 2021 Non-Current 5 851 4 220 Non-Current 4 584 5 851 Current portion as at January 1, 362 371 Current portion as at December 31, 437 362 Total Recoverable Cash Advances as at January 1, 6 213 4 590 Total Recoverable Cash Advances as at December 31, 5 021 6 213 The Group receives government support in the form of recoverable cash advances from the Walloon Region in order to compensate the research and development costs incurred by the Group. Refer to notes 3 and 24. At December 31, 2022, the Group has been granted recoverable cash advances amounting to €25.8 million related active contracts. Out of this amount: i) €21.8 million have been received to date; ii) €2.5 million should be received in 2023 or later depending on the progress of the different programs partially funded by the Region; iii) €1.5 million have been decommitted due to the end of the expenses submission period linked to the R&D period. In addition, the Group has received recoverable cash advances amounting to €15.3 million related to contracts for which the exploitation has been abandoned (mainly related to the C-Cure For further details, reference is made to the table below which shows, for active contracts (i) the year for which amounts under those agreements have been received and initially recognized on the statement of financial position for the financial liability and deferred grant income components and (ii) a description of the specific characteristics of those recoverable cash advances including repayment schedule and information on other outstanding advances. Underlying R&D is ongoing. In 2023 and beyond, the Group will have to make exploitation decisions on the remaining RCAs (agreements numbered 8212, 8436 and 8516). (in €‘000) Amounts received for the years Amounts to be received As at Id Project Contractual Prior 2021 2022 Cumulated 2023 and Amounts Status Amount 5915 C-Cathez 910 910 — — 910 — — Exploitation 740 6633 C-Cathez 1 020 1 020 — — 1 020 — — Exploitation 306 7027 C-Cathez 2 500 2 500 — — 2 500 — — Exploitation 675 7502 CAR-T Cell 2 000 2 000 — — 2 000 — — Exploitation 100 7685 THINK 3 496 3 496 — — 3 496 — — Exploitation 105 8087 CYAD01 - Deplethink 2 492 2 070 — — 2 070 — 421 Exploitation — 8088 CYAD02 - Cycle1 3 538 1 500 746 222 2 468 — 1 071 Exploitation — 1910028 CwalityCAR 2 102 749 199 1 113 2 061 — 41 Exploitation — 8212 CYAD-101 3 300 825 1 370 775 2 970 330 — Research — 8436 Immunicy 3 394 1 697 — 348 2 045 1 349 — Research — 8516 New engagers 1 095 — 274 — 274 821 — Research — Total 25 847 16 767 2 589 2 458 21 814 2 500 1 533 1 926 Regarding active contracts (in exploitation and research status): The contract 5915 has the following specific characteristics: • funding by the Region covers 70% of the budgeted project costs; • certain activities have to be performed within the Region; • in case of an outlicensing agreement or a sale to a third party, the Group will have to pay 10% of the price received (excl. of VAT) to the Region; • sales-independent reimbursements, sales-dependent reimbursements, and amounts due in case of an outlicensing agreement or a sale to a third party, are, in the aggregate, capped at 100% of the principal amount paid out by the Region; • sales-dependent reimbursements payable in any given year can be set-off • the amount of sales-independent reimbursement and sales-dependent reimbursement may possibly be adapted in case of an outlicensing agreement, a sale to a third party or industrial use of a prototype or pilot installation, when obtaining the consent of the Walloon Region to proceed thereto. The RCA liability associated to the contract 5915 amounted to €0.2 million. The other contracts have the following specific characteristics: • funding by the Region covers from 45% to 70% of the budgeted project costs; • certain activities have to be performed within the EU; • sales-independent reimbursements represent in the aggregate 30% of the principal amount; • sales-independent reimbursements and sales-dependent reimbursements are, in the aggregate (including the accrued interests), capped at 200% of the principal amount paid out by the Region; • interests (at Euribor 1 year (as applicable on the first day of the month in which the decision to grant the relevant RCA was made + 100 basis points) accrue as of the 1st day of the exploitation phase; • the amount of sales-independent reimbursement and sales-dependent reimbursement may possibly be adapted in case of an outlicensing agreement, a sale to a third party or industrial use of a prototype or pilot installation, when obtaining the consent of the Region to proceed thereto. • in case of bankruptcy, the research results obtained by the Group under those contracts are expressed to be assumed by the Region by operation of law. The RCA liability associated to the other contracts amounted to €4.8 million, which mainly The table below summarizes, in addition to the specific characteristics described above, certain terms and conditions for the recoverable cash advances: Contract number Research phase Percentage Turnover- Turnover-independent Interest Amounts (€’000) 5915 01/08/08-30/04/11 70 % 5.00 % €40k in 2012 and €70k each year after N/A 10% with a minimum of 100/Y 6633 01/05/11-30/11/12 60 % 0.27 % From €10k to €51k starting in 2013 until 30% of advance is reached Starting 01/06/13 N/A 7027 01/11/12-31/10/14 50 % 0.33 % From €25k to €125k starting in 2015 until 30% of advance is reached Starting 01/01/15 N/A 7502 01/12/15-30/11/18 45 % 0.19 % From €20k to €50k starting in 2019 until 30% is reached. Starting 01/12/19 N/A 7685 01/01/17-31/12/19 45 % 0.33 % From €35k to €70k starting in 2019 until 30% is reached. Starting 01/01/21 N/A 8087 01/05/19- 30/06/21 45 % 0.22 % From €20k to €61k starting in 2022 until 30% is reached Starting 01/07/22 N/A 8088 01/05/19- 31/12/21 45 % 0.21 % From €25k to €74k starting in 2022 until 30% is reached Starting 01/01/22 N/A 1910028 06/06/19- 05/06/22 45 % 0.01 % From €21k to €41k starting in 2022 until 30% is reached Starting 06/06/22 N/A 8212 01/01/20- 30/06/23 45 % 0.46 % From €33k to €99k starting in 2024 until 30% is reached Starting 01/07/23 N/A 8436 01/11/20- 31/12/23 45 % 0.32 % From €34k to €102k starting in 2024 until 30% is reached Starting 01/01/24 N/A 8516 01/04/21-31/03/23 45 % 0.10 % From €11k to 33k starting in 2024 until 30% is reached Starting 01/04/23 N/A

Due Dates of the Financial Liab

Due Dates of the Financial Liabilities	12 Months Ended
	Dec. 31, 2022
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Due Dates of the Financial Liabilities	NOTE 20: DUE DATES OF THE FINANCIAL LIABILITIES The table below analyses the Group’s non-derivative relating Financial liabilities reported as at December 31, 2022: (€‘000) Total Less than one One to three Three to five More than five As at December 31, 2022 Lease liabilities (undiscounted) 259 141 118 — — Pension obligations 13 — — — 13 Advances repayable (current and non-current) 5 021 437 640 637 3 307 Total financial liabilities 5 293 578 758 637 3 320 Financial liabilities reported as at December 31, 2021: (€‘000) Total Less than one One to three Three to five More than five As at December 31, 2021 Lease liabilities (undiscounted) 2 965 1 057 1 431 477 — Pension obligations 53 — — — 53 Advances repayable (current and non-current) 6 213 362 616 740 4 495 Total financial liabilities 9 231 1 419 2 047 1 217 4 548

Other Non-Current Liabilities

Other Non-Current Liabilities	12 Months Ended
	Dec. 31, 2022
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Other Non-Current Liabilities	NOTE 21: OTHER NON-CURRENT (€‘000) As at December 31, 2022 2021 Onerous contracts - non-current 124 — Other non-current 134 164 Total Other non-current 258 164 As of December 31, million in order to cover the contractual obligations, mainly on clinical activities follow-up CYAD-02, CYAD-101 CYAD-211. non-current million. The current portion of the provision is million as of December 31, 2022 (see note 22). As of December 31, 2021, the Group recorded a non-current million regarding a non-refundable, non-creditable non-current is million.

Trade Payables and Other Curren

Trade Payables and Other Current Liabilities	12 Months Ended
	Dec. 31, 2022
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Trade Payables and Other Current Liabilities	NOTE 22: TRADE PAYABLES AND OTHER CURRENT LIABILITIES (€‘000) As at December 31, 2022 2021 Total Trade payables 4 752 6 611 Social security 94 332 Payroll accruals 1 294 1 798 Onerous contracts - current liabilities 2 113 388 Other current grant liabilities 889 1 096 Other current liabilities 710 2 338 Total Other current liabilities 5 100 5 952 Total Trade payables and other current liabilities 9 852 12 563 Trade payables Trade payables are non-interest-bearing liabilities and are normally settled on 90-day terms. Their decrease is mainly attributable to the timing of the expenses and the related payments combined with a decrease of activities after the sale of CTMU activities and the strategic shift from an organization focused on clinical development to one prioritizing R&D discovery and the monetization of its IP portfolio through partnerships, collaborations and license agreements through the second semester of the year. The Group recognized estimated accruals for invoices to receive based on estimated amounts of rendered services or delivered goods during the year 2022 but not yet invoiced as per December 31, 2022 for an amount of Other current liabilities As of December 31, 2022, the decrease on social security and payroll accruals of €0.7 million compared to December 31, 2021 is mainly related to the headcount reduction in 2022. As of December 31, 2021, the provision for onerous contracts was related to the Group’s decision to discontinue the development of CYAD-01. The other current liabilities attached to RCA’s and other grants are mainly explained by the excess of cash proceeds compared to the eligible expenses. The decrease compared to year-end Other current liabilities decreased by €1.6 million, which is mainly explained by repayment of R&D tax credit to the federal government in the amount of €1.9 million related to the year s 2015, offset by an increase of deferred revenue by ell C-Cathez No discounting was performed to the extent that the amounts do not present payments terms longer than one year at the end of each financial year presented.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2022
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Financial Instruments	NOTE 23: FINANCIAL INSTRUMENTS Financial instruments not reported at fair value on statement of financial position The carrying and fair values of financial instruments that are not reported at fair value in the consolidated financial statements were as (€‘000) As at December 31, 2022 Financial assets at Fair value Financial Assets (‘Amortized cost’ category) within: Non-current — — Other non-current 264 264 Trade receivables and other current assets 1 118 1 118 Short-term investments — — Cash and cash equivalents 12 445 12 445 Total 13 827 13 827 For the above-mentioned financial assets, the carrying amount as per December 31, 2022, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2022 Financial liabilities at Fair value Financial Liabilities (‘Financial liabilities at amortized cost’ category) within: Lease liabilities 255 255 RCAs liability 5 021 5 021 Trade payables 4 752 4 752 Total 10 028 10 028 For the above-mentioned financial liabilities, the carrying amount as per December 31, 2022, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2021 Financial assets at Fair value Financial Assets (‘Amortized cost’ category) within: Non-current 2 209 2 209 Other non-current 262 262 Trade receivables and other current assets 668 668 Short-term investments — — Cash and cash equivalents 30 018 30 018 Total 33 157 33 157 For the above-mentioned financial assets, the carrying amount as per December 31, 2021, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2021 Financial liabilities at Fair value Financial Liabilities (‘Financial liabilities at amortized cost’ category) within: Finance lease liabilities 2 632 2 632 RCAs liability 6 213 6 213 Trade payables and other current liabilities 6 611 6 611 Total 15 456 15 456 For the above-mentioned financial liabilities, the carrying amount as per December 31, 2021, is a reasonable approximation of their fair value. Financial instruments reported at fair value on statement of financial position Contingent consideration and other financial liabilities are reported at fair value in the statement of financial position using Level 3 fair value measurements for which the Group developed unobservable inputs. (€‘000) As at December 31, 2022 Level I Level II Level III Total Liabilities Contingent consideration and other financial liabilities — — — — Total Liabilities — — — — (€‘000) As at December 31, 2021 Level I Level II Level III Total Liabilities Contingent consideration and other financial liabilities — — 14 679 14 679 Total Liabilities — — 14 679 14 679 After initial recognition, contingent consideration liabilities are re-measured The change in the balance is detailed as follows: (€‘000) For the year ended 2022 2021 Opening balance Contingent consideration at January 1, 14 679 15 526 Milestone payment — — Fair value adjustment (14 679 ) (847 ) Closing balance Contingent consideration at December 31, — 14 679 The contingent consideration and other financial liabilities refer to the acquisition of the Group’s immuno-oncology platform and corresponds to the fair value of the potential future payments due to Celdara Medical, LLC and Dartmouth College (as disclosed within note 34). The valuation is prepared by the Finance Team on a quarterly basis and reviewed by the Management. The Management’s key assumptions about projected cash flows when determining fair value less costs to sell are the same key assumptions than for impairment testing purposes (see note 7). There has not been any change in valuation technique in 2022 compared to 2021, at the exception of the change on key assumptions about projected cash flows as described below. As documented in the notes 1 and 7, Management had to conclude on the full reversal of the contingent consideration and other financial liabilities associated the potential future payments due to Celdara Medical, LLC and Dartmouth College associated to the Group’s immuno-oncology platform at December 31, 2022. This accounting conclusion, which reflects a picture of the situation at December 31, 2022, doesn’t affect the Management’s commitment to continue the exploitation of these IPs in its new strategy Celyad 2.0. As soon as a future event (such as a firm sublicense or collaboration contract) will increase the probability of the projected future cash outflow due to Celdara Medical, LLC and Dartmouth College, indicating that the probability is more than remote, the Group will reassess the contingent consideration and other financial liabilities proportionally to the revised fair value of such consideration. For comparative purpose, as of December 31, 2021, the liability evolution reflects the development of the Group’s product candidates using CAR T technology and their progress towards market approval in both autologous and allogeneic programs, as well as the update of its underlying business plans and revenue forecast. As of December 31, 2021, Management’s key assumptions (assumptions to which the unit’s or group of units’, recoverable amount is most sensitive) about projected cash flows when determining fair value less costs to sell are the same key assumptions was utilized for impairment testing purposes (see note 7): • Discount rate (WACC) The Management had determined that the Weighted Average Cost of Capital (WACC) was 20-Y, wa • Projected Revenue Management had estimated the projected revenue (using cash flow projections ending in 2040) based on the following components: total market and market share, time-to-market, • Probabilities of Success (PoS) Management had estimated the PoS based on Clinical Development Success Rates observed by independent business intelligence consulting companies for hematological and solid tumor diseases. Probability of the Group’s product candidates reaching the market used were updated based on most recent Clinical Development Success Rates observed by independent business intelligence consulting companies for hematological and solid tumor diseases and incorporate data for clinical development success rates from 2011 – 2020, which the Group believed was a more accurate reflection of clinical development success rates across stage of development and in aggregate, as follows: PoS Phase Phase I to Phase Phase II to Phase Phase III to BLA BLA to Cumulative PoS CYAD-02 100 % 50 % 28 % 60 % 90 % 7.5 % CYAD-101 100 % 49 % 23 % 43 % 93 % 4.6 % As of December 31, 2021, the change in fair value of the liability was mainly due to: • The update of the assumptions associated with the timing of the potential commercialization of the Group’s allogenic CYAD-101 • The update of the assumptions associated with the timing, development and the potential commercialization of the Group’s autologous CYAD-02 • The update in WACC used for fair value measurement purposes at December 31, 2021; • The revaluation of the U.S. dollar against the Euro; and • The updated assumptions on Probability of Success (PoS) associated with the Group’s CAR T programs.

Changes in Liabilities Arising

Changes in Liabilities Arising from Financial Activities	12 Months Ended
	Dec. 31, 2022
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Changes in Liabilities Arising from Financial Activities	NOTE 24: CHANGES IN LIABILITIES ARISING FROM FINANCIAL ACTIVITIES The change in bank loans balances is detailed as follows: BANK LOANS FINANCIAL LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, — 37 Payments — (37 ) Closing balance at December 31, — — The change in lease liability balances is detailed as follows: LEASES FINANCIAL LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, 2 632 3 602 New leases 170 129 Payments (896 ) (1 099 ) Remeasurement (1 651 ) — Closing balance at December 31, 255 2 632 New leases 2022 are mainly related to indexation on lease regarding properties. The remeasurement of the lease liabilities is mainly driven by the early termination of the leases on properties during the fourth quarter of 2022. The change in recoverable cash advance liability balances is detailed follows RECOVERABLE CASH ADVANCE LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, 6 213 4 590 Repayments (230 ) (280 ) Proceeds - Liability component 485 1 575 Remeasurement (1 447 ) 328 Closing balance at December 31, 5 021 6 213 The RCAs are initially recognized as a financial liability at fair value, calculated based on present value of future repayment of grants (using initial effective discount rates ranging between 0% and 7% for the fixed part and between 13% to 25% for the variable part, depending on RCAs listed in note 19), determined as per IFRS 9. The benefit (RCA grant component) consisting in the difference between the cash received (RCA proceeds) and the financial liability’s fair value (RCA liability component) is treated as a government grant in accordance with IAS 20 The RCAs liability component (RCA financial liability) is subsequently measured at amortized cost using the cumulative catch-up The change in the recoverable cash advances liability at the statement of financial position date mainly reflects both the new grants received in current year as well as the remeasurement of the liability at amortized cost, based on the Group’s updated business plan and related cash flow projections (see note 28). The year-end C-Cathez As documented in the notes 1 and 7, Management had to conclude that the possibility of any cash flow, associated with CAR T-cell and NKG2D-based therapies are remote and thus the fair value of the sales dependent liability is estimated to be zero, resulting remeasurement gain 1.4

Revenues

Revenues	12 Months Ended
	Dec. 31, 2022
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Revenues	NOTE 25: REVENUES (€‘000) For the year ended December 31, 2022 2021 2020 Out-licensing — — — Other revenue — — 5 Total — — 5 The Group’s license and collaboration agreements have generated no revenue for the year ended December 31, 2022 similar to the year ended December 31, 2021. The Group did not enter into any new license agreements for the 12-month The Group does not expect to generate material revenue unless and until the Group concludes partnerships with outside parties around the licensing of the patents around allogeneic CAR T-cell

Operating Expenses

Operating Expenses	12 Months Ended
	Dec. 31, 2022
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Operating Expenses	NOTE 26: OPERATING EXPENSES The operating expenses are made of the next three components: • Research & development expenses • General and administrative expenses • Non-recurring Research and development expenses The following table is a summary of manufacturing expenses, clinical, quality and regulatory expenses and other research and development expenses, which are aggregated and presented as research and development expenses in the Group’s consolidated financial statements. (€‘000) For the year ended December 31, 2022 2021 2020 Employee expenses 9 062 9 475 8 564 Clinical study costs 4 280 4 000 5 555 Preclinical study costs 1 233 2 473 1 976 Depreciation 1 231 1 276 1 511 IP filing and maintenance fees 831 353 230 Rent and utilities 610 670 800 Share-based payments 425 644 927 Process development and scale-up 396 770 1 056 Consulting fees 320 568 372 Travel & Living 126 85 116 Delivery systems — — 47 Others 415 459 369 Total R&D expenses 18 928 20 773 21 522 The changes in the R&D expenses are mainly driven by: • The decrease of employee expenses mainly related to headcount reduction • The increase on clinical study costs mainly due to the new provision for onerous contracts for a total amount of €2.2 million in order to cover the contractual obligations after the Group’s decision to discontinue the development of its remaining clinical programs CYAD-02, CYAD-101 CYAD-211 22 • The decrease of preclinical activities after the Group’s decision to adopt and implement over the last few months of the year 2022 the new business strategy to focus on discovery research in areas of expertise where it can leverage the differentiated nature of its platforms; • The increase on IP filing and maintenance fees in line with the new business strategy which has been adopted and implemented over the last few months of the year 2022 to focus on maximizing the Group’s intellectual property (IP) portfolio; • The decrease of the expenses associated with the share-based payments (non-cash • The decrease of process development costs after the Group’s decision to adopt and implement over the last few months of the year 2022 the new business strategy to focus on discovery research and discontinue the development of clinical programs. Research and development expenses totaled €20.8 million for the year ended December 31, 2021, which represent ed CYAD-101, CYAD-211 CYAD-203). was • The increase of employee expenses mainly related to movement of employees through the year ended December 31, 2021 to support the Group’s preclinical and clinical programs • The increase of preclinical activities associated with the CYAD-203 • The decrease of process development and clinical development after the Group’s decision in the fourth quarter of CYAD-01; • The decrease of process development associated to the transition from preclinical to clinical development of the CYAD-211 • The decrease of the expenses associated with the share-based payments (non-cash , mainly related to the decrease in the fair market value of stock options issued General and administrative expenses (€‘000) For the year ended December 31, 2022 2021 2020 Employee expenses 3 801 3 575 3 363 Consulting fees 2 870 2 254 1 747 Insurances 1 967 1 642 1 182 Share-based payments 1 199 1 529 1 855 Communication & Marketing 239 434 454 Depreciation 209 243 320 Travel & Living 115 31 91 Rent 109 50 87 Post-employment benefits (55 ) (7 ) 19 Other 92 157 197 Total General and administration 10 546 9 908 9 315 General and Administrative expenses increased by € million over the year ended December 31, 2022, which represents an increase of % compared to 2021. The increase in insurances costs (D&O insurance principally) and consulting fees associated with legal and capital raise opportunities have been partially offset by the decrease of expenses associated with share-based payments (non-cash expenses) related to the warrants plan offered to the employees, managers and directors, mainly related to the decrease in the fair market value of stock options issued in 2022. General and administrative expenses increased by € million over the year ended December 31, 2021, which represented an increase of % compared to 2020. The increase in insurances costs (D&O insurance principally) and consulting fees associated with legal, recruitment and capital raise opportunities had been partially compensated by the decrease of the expenses associated with the share-based payments (non-cash expenses) related to the warrants plan offered to the Group’s employees, managers and directors.

Employee Benefit Expenses

Employee Benefit Expenses	12 Months Ended
	Dec. 31, 2022
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Employee Benefit Expenses	NOTE 27: EMPLOYEE BENEFIT EXPENSES As of December 31, 2022, we employed 28 full-time employees, 3 part-time employees, 7 members of the Executive Committee (among them 3 are under management services agreement), and 1 manager under (€‘000) For the year ended December 31, 2022 2021 2020 Salaries, wages and fees 7 470 7 975 7 139 Executive Committee compensation 3 599 3 115 2 773 Share-based payments 1 624 2 172 2 782 Social security 1 237 1 444 1 487 Post-employment benefits 147 251 263 Hospitalization insurance 226 142 146 Other benefit expense 128 116 138 Total Employee expenses 14 432 15 215 14 727 Total employee expenses decreased in 2022 compared to 2021. Salaries, wages and fees expenses decreased compared to 2021, which reflects the impact of the reorganization of the Group (including one-off expenses), consistent with a total staff full time equivalent (“FTE”) reduction of 16.6 % for the year 2022. The increase of the Executive Committee compensation is due to the its reorganization through the year 2022 (including one-offs expenses) which is compensated by the decrease of the expenses associated with the share-based payments (non-cash expenses) related to the warrants plan offered to the employees, managers and directors, mainly related to the decrease in the fair market value of stock options issued in 2022. Total employee expenses increased in 2021 compared to 2020. Salaries, wages and fees expenses show a net increase year-on-year, which reflects the organic growth of the Group, in line with a total staff FTE increased by % at December 31, 2021. Staff full time equivalent (“FTE”) For the year ended December 31, 2022 2021 2020 Research & Development 82.6 94.1 81.7 General and Administration 11.0 18.2 16.6 Total Staff FTE 93.6 112.3 98.3

Other Income And Other Expenses

Other Income And Other Expenses	12 Months Ended
	Dec. 31, 2022
Other Income And Expenses [Abstract]
Other Income And Other Expenses	NOTE 28: OTHER INCOME AND OTHER EXPENSES Other income (€‘000) For the year ended December 31, 2022 2021 2020 Grant income (RCA’s) 1 137 2 731 2 311 Grant income (Other) 910 1 448 779 Remeasurement of RCA’s 1 447 — 933 R&D tax credit 462 687 657 Gain on sale of CTMU activities 5 187 — — Gain on sales of Property, plant & equipment — — 35 Remeasurement of Leases 169 — — Other 48 43 17 Total Other Income 9 360 4 909 4 731 In 2022, other income is mainly related to: • Grant income (RCAs): additional grant income has been recognized in 2022 on grants in the form of recoverable cash advances (RCAs) for contracts numbered 8212, 8436 and 1910028. In accordance with IFRS standards, the Company has earned grants for the period amounting to € million, out of which € million is accounted for as a financial liability (see notes 19 and 24) and the remaining € 1.1 million as a grant income. The decrease compared to December 31, 2021 is mainly associated with the decrease on additional grant income recognized on these conventions due to advancement of the subsidized programs; • The remeasurement income on the recoverable cash advances (RCAs) of €1.4 million for the year 2022 is mainly related to the Group decision to discontinue its remaining clinical programs (see note 24), while the • Grant income (Others): additional grant income has been recognized in 2022 on grants received from the regional government (contract numbered 8516), not referring to RCAs and not subject to reimbursement. The decrease compared to December 31, 2021 is mainly due to grant income recognized on grants received from the Federal Belgian Institute for Health Insurance Inami (€0.3 million) for which no revenue has been recognized in 2022 and from the regional government (contracts numbered 8066 and 8516 for €1.1 million) as the convention 8066 has been closed in 2021; • R&D tax credit: the current year income decreased compared to December 31, 2021 due to lower eligible expenses on clinical activities and prioritization of discovery research in areas of expertise where it can leverage the differentiated nature of the Group’s platforms; • Gain on sale of CTMU activities results from the terms of the asset purchase agreement between Celyad Oncology and Cellistic under which Cellistic agreed to acquire Celyad Oncology’s Manufacturing Business Unit for a total consideration of € million (see note 5.1). The book value of assets sold to Cellistic was € million (see note 5.7) and allocated goodwill totaled € million (see note 5.6.1); and • Remeasurement of leases: results from the difference between the decrease in the lease liability and the decrease in the right-of-use asset both primarily driven by the termination of leases associated to CTMU facilities and the termination of the current lease associated to the corporate offices before their relocation in 2023. In 2021, other income was mainly related to: • Grant income (RCAs): additional grant income had been recognized in 2021 on grants in the form of recoverable cash advances (RCAs) for contracts numbered 8087, 8088, 8212, 8436 and 1910028. According to IFRS standards, the Company had earned grants for the period amounting to €2.7 million and a liability component of €1.6 million was accounted for as a financial liability. The increase compared to December 31, 2020 is mainly associated with additional grant income recognized on new conventions signed during the last quarter of 2020 (contracts numbered 8212 and 8436) and on convention numbered 1910028, partly compensated by the decrease on grant income recognized on conventions associated to autologous programs (contract numbered 7685, 8087 and 8088); • Grant income (Others): additional grant income had been recognized in 2021 on grants received from the Federal Belgian Institute for Health Insurance Inami (€0.3 million) and from the regional government (contracts numbered 8066 and 8516 for €1.1 million), not referring to RCAs and not subject to reimbursement. The increase compared to December 31, 2020 was mainly due to grant income recognized on new convention signed in the last quarter of 2021 with the regional government (contract numbered 8516); • the remeasurement income on the recoverable cash advances (RCAs) of €0.9 million for the year 2020, which had been mainly related to the Group decision to update assumptions associated with the timing of the potential commercialization of the Group’s autologous AML/MDS CAR T program, while the remeasurement on the recoverable cash advances (RCAs) was an expense for the year ended December 31, 2021; and • with respect to R&D tax credit, the income was predicated on a R&D tax credit recorded (€0.7 million), which had been updated taking into account all information available at this date and was in line with previous year. Other expenses (€‘000) For the year ended December 31, 2022 2021 2020 Clinical Development milestone payment — — 69 Remeasurement of RCA’s — 328 — Loss on disposals of Property, plant & equipment 132 1 10 Loss on disposals of Intangible assets 58 — — Amendment fees on license agreement — 1 104 — Other 149 33 35 Total Other Expenses 339 1 466 114 As of December 31, 2022, the decrease of other expenses compared to December 31, 2021, is mainly related to the amendment fees on license agreement with Dartmouth for €1.1 million in 2021, while there has been no such amendment in 2022. For the year ended December 31, 2020, other expenses had mainly referred to clinical development milestones for (€ million) paid to Dartmouth after that the Group successfully dosed the first patient with CYAD-02 in CYCLE-1 trial for r/r AML and MDS treatment.

Change In Fair Value Of Conting

Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets	12 Months Ended
	Dec. 31, 2022
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Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets	NOTE 29: CHANGE IN FAIR VALUE OF CONTINGENT CONSIDERATION AND IMPAIRMENT OF ONCOLOGY INTANGIBLE ASSETS Change in fair value of contingent consideration (€‘000) For the year ended December 31, 2022 2021 2020 Change in fair value of contingent consideration 14 679 847 9 228 Total Change in fair value of contingent consideration 14 679 847 9 228 The fair value adjustment (€ million, non-cash expenses) relates to the reassessment as of December 31, 2022, of the contingent consideration and other financial payable related to the potential future payments to Celdara Medical, LLC and Dartmouth College associated with the Group’s immuno-oncology platform. For further details regarding the change in fair value of contingent consideration, refer to note 23. The fair value adjustment (€0.8 million, non-cash 1 • The update of the assumptions associated with the timing of the potential commercialization of the Group’s allogenic CYAD • The update of the assumptions associated with the timing, development and the potential commercialization of the Group’s autologous CYAD-02 • The update in WACC used for fair value measurement purposes at December 31, 2021; • The revaluation of the U.S. dollar against the Euro; and • The updated assumptions on Probability of Success (PoS) associated with the Group’s CAR T programs. As of December 31, 2020, the change in fair value of the contingent consideration and other financial liabilities was mainly driven by updated assumptions associated with the timing of the potential commercialization of the Company’s autologous AML/MDS CAR T program which had been delayed by one year. Impairment of Oncology intangible assets (€‘000) For the year ended December 31, 2022 2021 2020 Impairment of Oncology intangible assets (35 084 ) — — Total Impairment of Oncology intangible assets (35 084 ) — — Management performed an annual impairment test on goodwill and on ‘indefinite lived assets’ that are not amortized in accordance with the accounting policies stated in note 3. The impairment test has been performed at the level of the immuno-oncology segment corresponding to the CGU to which the goodwill and the IPR&D belong as well as the Horizon Discovery’s shRNA platform. For further details regarding the impairment of oncology intangible assets for the year ended December 31, 2022, refer to note 7.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
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Leases	NOTE 30: LEASES Amounts recognized in the consolidated statements of financial position (€’000) As at December 31, 2022 2021 Property, Plant and Equipment owned (excluding right-of-use 86 1 033 Right-of-use 223 2 215 Total Property, Plant and Equipment 309 3 248 The consolidated statements of financial position shows the following amounts relating to leases for which the Group is a lessee: (€’000) Property Vehicles Equipment Total Cost At January 1, 2021 3 001 429 1 491 4 920 Additions 24 67 — 91 Disposals — (41 ) — (41 ) Transfers — — (950 ) (950 ) At December 31, 2021 3 025 454 541 4 020 Additions 146 7 — 153 Disposals (3 171 ) (131 ) — (41 ) At December 31, 2022 — 331 541 872 Accumulated depreciation At January 1, 2021 (827 ) (165 ) (924 ) (1 916 ) Depreciation charge (454 ) (117 ) (309 ) (880 ) Disposals — 41 — 41 Transfers — — 950 950 At December 31, 2021 (1 281 ) (241 ) (283 ) (1 805 ) Depreciation charge (439 ) (105 ) (118 ) (663 ) Disposals 1 721 98 — 1 819 At December 31, 2022 — (248 ) (401 ) (649 ) Net book value Cost 3 025 454 541 4 020 Accumulated depreciation (1 281 ) (241 ) (283 ) (1 805 ) At December 31, 2021 1 744 213 258 2 215 Cost — 331 541 872 Accumulated depreciation — (248 ) (401 ) (649 ) At December 31, 2022 — 83 140 223 The disposals for the year 2022 are mainly related to the termination of the lease agreement associated to the CTMU facilities and the termination of the lease agreement for current corporate offices before their relocation in 2023. See note 8. Amounts recognized in the consolidated statements of comprehensive loss The consolidated statements of comprehensive loss show the following amounts relating to leases: (€’000) For the 12-month period ended December 31, 2022 2021 2020 Depreciation charge of right-of-use Property 439 454 428 Vehicles 105 76 75 Equipment 118 309 567 Interest on lease liabilities (including in Financial expenses) 1 150 217 259 Interest on sublease receivable (including in Financial income) 1 (11 ) (26 ) (46 ) Variable lease payments not included in the measurement of lease liabilities — — — Remeasurement of Leases (169 ) — — Expenses relating to short-term leases and leases of low-value 126 137 166 Total expenses related to leases 758 1 167 1 449 1 Interests on leases are presented as operating cash flow. The net income from the remeasurement of leases primarily results from termination of leases Total cash outflow for leases (€’000) For the 12-month period ended December 31, 2022 2021 2020 Total cash outflow for leases 1 172 1 453 1 681

Financial Income and Expenses

Financial Income and Expenses	12 Months Ended
	Dec. 31, 2022
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Financial Income and Expenses	NOTE 31: FINANCIAL INCOME AND EXPENSES (€’000) For the year ended December 31, 2022 2021 2020 Interest finance leases 150 217 260 Interest on overdrafts and other finance costs 33 21 19 Interest on RCAs 14 17 18 Foreign Exchange differences — — 136 Finance expenses 198 255 434 Finance income on the net investment in lease 11 26 46 Interest income bank account 1 1 5 Foreign Exchange differences 173 5 — Other financial income — 112 166 Finance income 185 144 217 Net Financial result (13 ) (111 ) (217 ) The net financial result increased from a net financial loss of € million for the year ended December 31, 2021 to € million of net financial loss for the year ended December 31, 2022, which is mainly driven by the increase of gain on foreign exchange differences for €0.2 million due to the revaluation of the USD through the year ended December 31, 2022 partly compensated by the decrease of interest expenses on finance leases for € million mainly due to termination of leases which occurred through the year 2022. The net financial result had increased from a net financial loss of €0.2 million for the year ended December 31, 2020 to €0.1 million of net financial loss for the year ended December 31, 2021, which was mainly driven by the decrease from €0.1 million of loss on foreign exchange differences due to the revaluation of the USD through the year ended December 31, 2021 and its impact on the valuation of the Mesoblast receivable.

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2022
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Income Tax	NOTE 32: INCOME TAX The Group reports income taxes in the income statement as detailed below: (€‘000) For the year ended December 31, 2022 2021 2020 Current tax (expense) / income (65 ) (10 ) — Deferred tax (expense) / income — — — Total income tax expense in profit or loss (65 ) (10 ) — The Group has a history of losses. The (€‘000) For the year ended December 31, 2022 2021 2020 Loss before tax (40 870 ) (26 502 ) (17 204 ) Permanent differences Tax disallowed expenses 1 248 1 185 1 092 Share-based payment 1 624 2 172 2 782 Nominal tax rate 25.00 % 25.00 % 25.00 % Income tax at nominal tax rate 1 9 500 5 786 3 333 Deferred tax assets not recognized (9 565 ) (5 796 ) (3 333 ) Effective tax expense (65 ) (10 ) — Effective tax rate 0 % 0 % 0 % 1 The difference in foreign tax rate in the US (25.80%) compared to the Belgian rate (25.00%) is not distinctively disclosed in this table due to non-materiality

Deferred Taxes

Deferred Taxes	12 Months Ended
	Dec. 31, 2022
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Deferred Taxes	NOTE 33: DEFERRED TAXES As having not yet reached the commercialization step, the Group accumulates tax losses that are carried forward indefinitely for offset against future taxable profits of the Group. Significant uncertainty exists however surrounding the Group’s ability to realize taxable profits in a foreseeable future leading the Group to not recognizing any net deferred tax assets in its statements of financial position. Deferred tax assets and liabilities are detailed below by nature of temporary differences for the current year: (€‘000) For the year ended December 31, 2022 Assets Liabilities Net Intangibles assets — (216 ) (216 ) Recoverable cash advances liability 1 226 — 1 226 Contingent consideration liability — — — Employee Benefits liability 3 — 3 Other temporary difference 272 — 272 Tax-losses 78 332 — 78 332 Unrecognized Gross Deferred Tax assets/(liabilities) 79 833 (216 ) 79 617 Netting by tax entity (216 ) 216 — Unrecognized Net Deferred Tax assets/(liabilities) 79 617 — 79 617 Deferred tax assets and liabilities are detailed below by nature (€‘000) For the year ended December 31, 2021 Assets Liabilities Net Intangibles assets — (2 709 ) (2 709 ) Recoverable cash advances liability 1 503 — 1 503 Contingent consideration liability 3 670 — 3 670 Employee Benefits liability 13 — 13 Other temporary difference — (586 ) (586 ) Tax-losses 72 671 — 72 671 Unrecognized Gross Deferred Tax assets/(liabilities) 77 857 (3 295 ) 74 562 Netting by tax entity (3 295 ) 3 295 — Unrecognized Net Deferred Tax assets/(liabilities) 74 562 — 74 562 The Group’s main deductible tax base relates to tax losses carried forward, which have indefinite term under both BE and US tax regimes applicable to its subsidiaries. The remaining temporary differences refer to differences between IFRS accounting policies and local tax reporting policies. The change in the Group’s net deferred tax asset balance is detailed below: UNRECOGNIZED DEFERRED TAX ASSET BALANCE ROLL FORWARD (€‘000) For the year ended 2022 2021 2020 Opening balance at January 1, 74 562 66 208 61 300 Temporary difference creation or reversal (606 ) (1 014 ) (2 981 ) Change in Tax-losses 5 661 8 820 8 064 Change in US tax rate applicable — 548 (176 ) Closing balance at December 31, 79 617 74 562 66 208 The net increase in the balance mainly relates to the additional losses reported for the current year. As of December 31, 2022, the Group has a total accumulated tax losses of €312.9 million, which generate unrecognized deferred tax assets, not subject to expiration.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2022
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Commitments	NOTE 34: COMMITMENTS Celdara Background In January 2015, the Group entered into an agreement with Celdara Medical, LLC, or Celdara in which the Group purchased all outstanding membership interests of OnCyte, LLC, or OnCyte. In connection with this transaction, the Group entered into an asset purchase agreement to which Celdara sold to OnCyte certain data, protocols, regulatory documents and intellectual property, including the rights and obligations under two license agreements between OnCyte and The Trustees of Dartmouth College, or Dartmouth, related to the Group’s CAR T development programs. In March 2018, the Group dissolved the affairs of its wholly owned subsidiary OnCyte. As a result of the dissolution of OnCyte, all the assets and liabilities of OnCyte were fully distributed to the Group including its license agreement with Dartmouth. Amended Asset Purchase Agreement In August 2017, the Group entered into an amendment to the asset purchase agreement described above. In connection with the amendment, the following payments were made to Celdara: (i) an amount in cash equal to $10.5 million, (ii) newly issued shares of Celyad valued at $12.5 million, (iii) an amount in cash equal to $6.0 million in full satisfaction of any payments owed to Celdara in connection with a clinical milestone related to the Group’s CAR-T NKR-2 Under the amended asset purchase agreement, the Group is obligated to make certain development-based milestone payments to Celdara up to $40.0 million, certain development-based milestone payments up to $36.5 million and certain sales-based milestone payments up to $156.0 million. The Group is required to make tiered single-digit royalty payments to Celdara in connection with the sales of CAR-T mid-single mid-twenties, The Trustees of Dartmouth College (“Dartmouth”) As described above, as a result of the Group’s acquisition of all of the outstanding membership interests of OnCyte and the asset purchase agreement among the Group, Celdara and OnCyte, OnCyte became the Group’s wholly-owned subsidiary and acquired certain data, protocols, regulatory documents and intellectual property, including the rights and obligations under two license agreements between OnCyte and Dartmouth. The first of these two license agreements concerned patent rights related, in part, to methods for treating cancer involving chimeric NK and NKP30 receptor targeted therapeutics and T cell receptor-deficient T cell compositions in treating tumor, infection, GVHD, transplant and radiation sickness, or the CAR-T anti-B7-H6 In August 2017, the Group and Dartmouth entered into an amendment agreement in order to combine its rights under B7H6 Agreement with its rights under the CAR-T non-refundable, non-creditable know-how know-how, mid-single low-single mid-single As further amended in December 2021, this agreement allows Dartmouth to terminate the amended license after April 30, 2026, extended from the prior date of April 30, 2024, in the event that Celyad fails to meet the specified minimum net sales obligations for any year ($10 million during first year of sales, $40 million during the second year of sales and $100 million during the third year of sales and every year of sales thereafter), unless Celyad pays to Dartmouth the royalty Celyad would otherwise be obligated to pay had Celyad met such minimum net sales obligation. Dartmouth may also terminate the license if Celyad fails to meet a milestone within the specified time period, unless Celyad pays the corresponding milestone payment. In connection with the December 2021 amendment, the Group agreed to certain protective provisions of any sublicenses and paid Dartmouth a non-refundable, non-creditable non-refundable, non-creditable paid In accordance with IFRS 3, these contingencies are recognized on the statement of financial position at year-end, Horizon Discovery / PerkinElmer In April and June 2018, the Group signed two research and development collaboration and license agreements with Horizon Discovery Group plc, or Horizon, to evaluate the utility of Horizon’s SMART vector shRNA reagents to reduce expression of one or more defined targets in connection with the development of the Group’s product candidates. The first agreement was focused on targets related to its autologous CAR-T CYAD-02. CAR-T CYAD-211 pre-clinical CYAD-203. In December 2018, the Group exercised its option to convert the second agreement into an exclusive license agreement, in connection with which the Group paid Horizon an up-front up-front CYAD-02. CYAD-211. Under these exclusive license agreements combined, Horizon is eligible to receive additional milestone payments in development, regulatory and commercial milestone payments, in addition to low single digit royalties on net sales, subject to customary reductions. In December 2020, Horizon Discovery was acquired by PerkinElmer, Inc. (Horizon/PKI). In 2021, Horizon/PKI informed the Group they believe the Group is in material breach of these agreements as a result of certain disclosures the Group has made in connection with its obligations as a publicly traded company in the United States and Belgium, although they have not formally delivered to the Group a notice of material breach or termination. The Group believes any such assertion of material breach would be without merit and the Group would expect to vigorously defend any such notice of material breach. Any dispute under these agreements would be subject to arbitration in The Hague under the International Chamber of Commerce Rules. The Group is currently in discussions with Horizon about possible amendments to these agreements in connection with which the Group would retain freedom to operate under the in-licensed Of note, the Group has filed patent applications which, if issued, would cover other aspects of the product candidates described above as well as products developed by third parties that deploy similar technology and targets. These patent applications encompass the downregulation of one or more of the targets covered under the Horizon/PKI agreements, the use of shRNA to downregulate such targets in immune cells and the combination of shRNAs with a chimeric antigen receptor in immune cells. The Group is also developing a second generation shRNA platform that does not incorporate any of the Horizon Discovery/Perkin Elmer, Inc. technology described above. The Group’s discontinued allogeneic CAR T product candidate, CYAD-101, Other commitments In 2021, the Group signed two license agreements. Under these license agreements, the licensors are eligible to receive additional milestone payments in development, regulatory and commercial milestone payments, in addition to low single digit royalties on net sales, subject to customary reductions, if the Group decided to continue the exploitation of these licenses. In 2022, the Group decides to stop the exploitation of these two licenses (see note 7). The Group has entered into a lease agreement for its new head quarter (Dumont 9 building in Mont-Saint-Guibert, Belgium) for total undiscounted lease payment of €0.5 million. This lease will commence from April 1, 2023. During the time needed for the set-up of its new offices of Dumont 9 building, we execute short term lease (less than 12 months) of a part of Belin 2 building from Cellistic for €0.3 million.

Relationships with Related Part

Relationships with Related Parties	12 Months Ended
	Dec. 31, 2022
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Relationships with Related Parties	NOTE 35: RELATIONSHIPS WITH RELATED PARTIES Remuneration of key management Key management consists of the members of t he As at December 31, 2022 2021 2020 Number of Executive Committee members 7 7 6 (€’000) For the year ended 2022 2021 2020 Short term employee benefits [1] 2 294 1 866 1 349 Post employee benefits 53 45 34 Share-based compensation 790 928 1 110 Other employment costs [2] 143 148 110 Management fees 1 200 1 163 1 335 Total benefits 4 480 4 150 3 939 Executive Committee outstanding fees payables 781 844 660 (1) Include salaries, social security, bonuses, lunch vouchers (2) Company cars The increase of the short term employees benefits as of December 31, 2022, include the one-off As at December 31, 2022 2021 2020 Number of warrants granted 489 700 395 000 220 000 Number of warrants lapsed (127 250 ) (30 000 ) (20 000 ) Cumulative outstanding warrants 696 400 921 000 556 000 Exercised warrants — — — Transactions with non-executive For the year ended December 31, (€‘000) 2022 2021 2020 Share-based compensation 230 337 396 Management fees 382 373 366 Total benefits 612 710 762 Non-executive 93 93 94 As at December 31, 2022 2021 2020 Number of warrants granted 40 000 150 000 80 000 Number of warrants lapsed (60 000 ) — (30 000 ) Number of exercised warrants — — — Cumulative outstanding warrants 230 000 340 000 220 000 Transactions with shareholders There were no transactions with the Group’s shareholders, for 2022, 2021 or 2020.

Loss per share

Loss per share	12 Months Ended
	Dec. 31, 2022
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Loss per share	NOTE 36: LOSS PER SHARE The loss per share is calculated by dividing loss for the year by the weighted average number of ordinary shares outstanding during the period. As the Group is incurring net losses, all of the outstanding warrants have an anti-dilutive effect. As such, there is no difference between the basic and the diluted earnings per share. In case the warrants would be included in the calculation of the loss per share, this would decrease the loss per share. (€’000) As at December 31, 2022 2021 2020 Loss of the year attributable to Equity Holders (40 935 ) (26 512 ) (17 204 ) Weighted average number of shares outstanding 22 593 956 15 604 014 13 942 344 Earnings per share (non-fully (1.81 ) (1.70 ) (1.23 ) Outstanding warrants 2 339 646 2 136 556 1 488 006

Events after the close of the f

Events after the close of the fiscal Year	12 Months Ended
	Dec. 31, 2022
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Events after the close of the fiscal Year	NOTE 37: EVENTS AFTER THE CLOSE OF THE FISCAL YEAR On January 1, 2023, the Company sold all the leasehold improvements, and furniture associated to the Group’s corporate offices located at Rue 1.3 million. The Company will use part of this money to refurbish and move to its new facility located at Rue Dumont 9, 1435 Mont-Saint-Guibert, Belgium. The move to these new spaces is expected in the fourth quarter of 2023. As from January 1, 2023, until the date the Company moves into the new corporate offices (Dumont 9), the Company leases its current facilities (Belin, 2) from Cellistic, under a new lease contract (see note 34). Effective January 9, 2023, the clinical team (8 employees) has joined the organization of ProPharma Group Holdings LLC, a global reputed CRO with whom Celyad has simultaneously entered into a service agreement for support relating to the closing of its clinical trials. The clinical trials remain under the Company responsibility as sponsor , There were no other subsequent events that have occurred between year-end

Accounting Principles (Policies

Accounting Principles (Policies)	12 Months Ended
	Dec. 31, 2022
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Subsidiaries	Subsidiaries Subsidiaries are all entities (including structured entities) over which the Group has control. The Group controls an entity when the Group is exposed to, or has rights to, variable returns from its involvement with the entity and has the ability to affect those returns through its power over the entity. Subsidiaries are fully consolidated from the date on which control is transferred to the Group. They are deconsolidated from the date control ceases. Inter-company transactions, balances and unrealized gains on transactions between group companies are eliminated. Unrealized losses are also eliminated. When necessary, amounts reported by subsidiaries have been adjusted to conform with the Group’s accounting policies.
Foreign currency translation	FOREIGN CURRENCY TRANSLATION Functional and presentation currency Items included in the financial statements of each of the Group’s entities are measured using the currency of the primary economic environment in which the entity operates (“the functional currency”). The consolidated financial statements are presented in Euros, which is the Group’s presentation currency. Transactions and balances Foreign currency transactions (mainly USD) are translated into the functional currency using the applicable exchange rate on the transaction dates. Monetary assets and liabilities denominated in foreign currencies are retranslated at the presentation currency spot rate of exchange ruling at the reporting date. Foreign currency exchange gains and losses arising from settling foreign currency transactions and from the retranslation of monetary assets and liabilities denominated in foreign currencies at the reporting date are recognized in the income statement. Non-monetary Non-monetary Group companies The results and financial position of all group entities that have a functional currency different from the presentation currency are translated into the presentation currency as follows: • Assets and liabilities for each statement of financial position presented are translated at the closing rate at the date of that statement of financial position; • Income and expenses for each income statement are translated at average exchange rate (unless this average is not a reasonable approximation of the cumulative effect of the rates prevailing on the transaction dates, in which case income and expenses are translated at the rate on the dates of the transactions); and • All resulting translation differences are recognized in other comprehensive income.
Revenue	REVENUE So far, the primary revenue generated by the Group relates to the sale of licenses.
Licensing revenue	Licensing revenue The Group enters into license and/or collaboration agreements with third-party biopharmaceutical partners. Revenue under these arrangements may include non-refundable Upfront payments License fees representing non-refundable Milestone payments Milestone payments represent amounts received from the Group’s customers or collaborators, the receipt of which is dependent upon the achievement of certain scientific, regulatory, or commercial milestones. Under IFRS 15, milestone payments generally represent a form of variable consideration as the payments are likely to be contingent on the occurrence of future events. Milestone payments are estimated and included in the transaction price based on either the expected value (probability-weighted estimate) or most likely amount approach. The most likely amount is likely to be most predictive for milestone payments with a binary outcome (i.e., the Group receives all or none of the milestone payment). Variable consideration is only recognized as revenue when the related performance obligation is satisfied, and the Group determines that it is highly probable that there will not be a significant reversal of cumulative revenue recognized in future periods. Royalty revenue Royalty revenues arise from the Group’s contractual entitlement to receive a percentage of product sales achieved by co-contracting co-contracting Sales of goods (medical devices) Sales of medical devices are recognized when the Group has fulfilled the performance obligations under the terms of the sales contract, which includes delivery of the promised goods.
Government Grants (Other operating income)	OTHER INCOME Government Grants The Group’s grant income reported under ‘Other income’ in the consolidated statement of comprehensive loss is generated from: (i) recoverable cash advances (RCAs) granted by the Regional government of Wallonia; (ii) R&D tax credits granted by the Belgian federal government; and (iii) grants received from the European Commission under the Seventh Framework Program (“FP7”), Federal Belgian Institute for Health Insurance (Inami) and Regional authorities. Government grants are recognized at their fair value (calculated based on present value of future repayment of grants) where there is reasonable assurance that the grant will be received, and the Group has complied with all attached conditions. Once a government grant is recognized, any related contingent liability (or contingent asset) is treated in accordance with IAS 37. Government grants relating to costs are deferred and recognized in the consolidated statement of comprehensive loss over the period necessary to match them with the costs that they are intended to compensate. Based on the nature of transactions, cash inflows received from government grants provide the entity with financing for the designated activity. They are in substance financing cash inflows consistent with the cash proceeds from RCAs and other grants and are disclosed in the consolidated statements of cash flows as “Cash Flow from financing activities”. The Group’s grant income is recognized in the consolidated statement of comprehensive loss under “Other income/expense” and as a non-cash Recoverable cash advances (RCAs) The Group receives grants from the Walloon Region in the form of recoverable cash advances (RCAs). RCAs are dedicated to support specific development programs. All RCA contracts, in essence, consist of three phases, i.e., the “research phase”, the “decision phase” and the “exploitation phase”. During the research phase, the Group receives funds from the Region based on statements of expenses. In accordance with IAS 20.10A and IFRS Interpretations Committee (IC)’s conclusion that contingently repayable cash received from a government to finance a research and development (R&D) project is a financial liability under IAS 32, ‘Financial instruments; Presentation’, the RCAs are initially recognized, concomitantly with the occurrence of subsidized expense, as a financial liability at fair value (calculated based on present value of future repayment of grants), determined as per IFRS 9. The benefit (RCA grant component) consisting in the difference between the cash received (RCA proceeds) and the above-mentioned financial liability’s fair value (RCA liability component) is treated as a government grant in accordance with IAS 20. The RCA grant component is recognized in profit or loss under “Other income” on a systematic basis over the periods in which the entity recognizes the underlying R&D expenses subsidized by the RCA. The fair market value adjustments to the RCA liability are recognized in the consolidated statement of comprehensive loss under “Other income/expense” and as a non-cash The RCAs liability contains two components: • The fixed part of the reimbursement of 30% is refundable based upon an agreed repayment schedule. The initial recognition at fair value is performed using the discount rate at the date of the convention and the assumption of exploitation until the end of repayment schedule. • The variable part (from 70% and up to 170%) is refundable to the extent of the revenue generated within exploitation phase. The initial recognition at fair value of the variable part of the component is based on probability-weighted discounted cash flows estimated using Key assumptions listed in note 7. The sales-independent reimbursements and sales-dependent reimbursements are, in the aggregate (including the accrued interests), capped at 200% of the principal amount paid out by the Walloon Region. The RCAs liability component (RCA financial liability) is subsequently measured at amortized cost using the cumulative catch-up At the end of the research phase, the Group should within a period of six months decide whether or not to exploit the results of the research phase (decision phase). The exploitation phase may have a duration of up to 20 years. In the event the Group decides to exploit the results under an RCA, the relevant RCA becomes contingently refundable, and the fair value of the RCA liability adjusted accordingly, if required. For more information on the potential financial consequences of these exploitation decisions in terms of potential reimbursements and sales percentage When the Group does not exploit (or ceases to exploit) the results of programs under an RCA, it has to notify the Region of this decision. This decision is the sole responsibility of the Group. The related liability is then discharged by the transfer of such results to the Region. Also, when the Group decides to renounce its rights to patents which may result from the research, title to such patents will be transferred to the Region. In that case, the RCA liability is extinguished and reflected in the statement of income (loss) under “Other income/expense”. R&D Tax credits Since 2013, the Group applies for R&D tax credits, a tax incentive measure for European SME’s established by the Belgian federal government. When capitalizing its R&D expenses under the tax reporting framework, the Group may either i) get a reduction of its taxable income (at current income tax rate applicable); or ii) if no sufficient taxable income is available, apply for the refund of the unutilized tax credits, calculated on the R&D expenses amount for the year. Such settlement occurs at the earliest 5 financial years after the tax credit application filed by the Group. Considering that R&D tax credits are ultimately paid by the public authorities, the related benefit is treated as a government grant under IAS 20 and booked into other income, in order to match the R&D expenses subsidized by the grant. Other government grants The Group has received and will continue to apply for grants from European (FP7), Regional authorities and Federal Belgian Institute for Health Insurance (Inami). These grants are dedicated to partially finance early stage projects such as fundamental research, applied research, prototype design, etc. To date, all grants received are not associated with any conditions. As per each grant agreement, grants are paid upon submission by the Group of a statement of eligible expenses. The Group incurs expenses first and then submits application for the grant receipt according to the terms of the grant agreement. These government grants are recognized in profit or loss under “Other income” on a systematic basis over the periods in which the entity recognizes the underlying R&D expenses subsidized.
Intangible assets	INTANGIBLE ASSETS The following categories of intangible assets apply to the current Group operations: Separately acquired intangible assets Intangible assets acquired from third parties are recognized at cost, if and only if it is probable that future economic benefits associated with the asset will flow to the Group, and that the cost can be measured reliably. Subsequent payments of contingent consideration are capitalized when incurred. Following initial recognition, intangible assets are carried at cost less any accumulated amortization and accumulated impairment losses. The useful life of intangible assets is assessed as finite, except for Goodwill. They are amortized over the expected useful economic life and assessed for impairment whenever there is an indication that the intangible asset may be impaired. The amortization period and the amortization method for an intangible asset with a finite useful life are reviewed at least at each financial year end. Changes in the expected useful life or the expected pattern of consumption of future economic benefits embodied in the asset are accounted for by changing the amortization period or method, as appropriate, and are treated as changes in accounting estimates and applied prospectively. The amortization expense on intangible assets with finite lives is recognized in the income statement in the expense category consistent with the function of the intangible asset.
Patents, Licences and Trademarks	Patents, Licenses and Trademarks Licenses for the use of intellectual property are granted for a period corresponding to the intellectual property of the assets licensed. Amortization is calculated on a straight-line basis over this useful life. Patents and licenses are amortized over the period corresponding to the intellectual property (IP) protection and are assessed for impairment whenever there is an indication these assets may be impaired. Indication of impairment is related to the value of the patent demonstrated by the preclinical and clinical results of the technology.
Software	Software Software only concerns acquired computer software licenses. Software is capitalized on the basis of the costs incurred to acquire and bring to use the specific software. These costs are amortized over their estimated useful lives of three five years
Goodwill	Intangible assets acquired in a business combination Goodwill Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Goodwill is measured as a residual at the acquisition date, as the excess of the fair value of the consideration transferred and the assets and liabilities recognized (in accordance with IFRS 3). Goodwill has an indefinite useful life and is not amortized but tested for impairment at least annually or more frequently whenever events or changes in circumstances indicate that goodwill may be impaired, as set forth in IAS 36 (Impairment of Assets). Goodwill arising from business combinations is allocated to cash generating units, which are expected to receive future economic benefits from synergies that are most likely to arise from the acquisition. These cash generating units form the basis of any future assessment of impairment of the carrying value of the acquired goodwill.
In process research and development costs	In-process The In-process Subsequent R&D expenditure can be capitalized as part of the IPR&D only to the extent that IPR&D is in development stage, i.e., when such expenditure meets the recognition criteria of IAS 38. In line with biotech industry practice, the Group determines that ‘development stage’ under IAS 38 is reached when the product candidate gets regulatory approval (upon Phase III completion). Therefore, any R&D expenditure incurred between the acquisition date and the development stage should be treated as part of research phase and expensed periodically in the income statement. Internally generated intangible assets Except qualifying development expenditure (discussed below), internally generated intangible assets are not capitalized. Expenditure is reflected in the income statement in the year in which the expenditure is incurred.
Research and development costs	Research and development costs Research costs are expensed as incurred. Development expenditures on an individual project are recognized as an intangible asset when the Group can demonstrate: a) The technical feasibility of completing the intangible asset so that it will be available for use or sale. b) Its intention to complete the intangible asset and use or sell it. c) Its ability to use or sell the intangible asset. d) How the intangible asset will generate probable future economic benefits. Among other things, the entity can demonstrate the existence of a market for the output of the intangible asset or the intangible asset itself or, if it is to be used internally, the usefulness of the intangible asset. e) The availability of adequate technical, financial and other resources to complete the development and to use or sell the intangible asset. f) Its ability to measure reliably the expenditure attributable to the intangible asset during its development. For the industry in which the Group operates, the life science industry, criteria a) and d) tend to be the most difficult to achieve. Experience shows that in the Biotechnology sector technical feasibility of completing the project is met when such project completes successfully Phase III of its development. For medical devices this is usually met at the moment of CE marking. Following initial recognition of the development expenditure as an asset, the cost model is applied requiring the asset to be carried at cost less any accumulated amortization and accumulated impairment losses. Amortization of the asset begins when development has been completed and the asset is available for use. It is amortized over the period of expected future benefit. Amortization is recorded in Research & Development expenses. During the period of development, the asset is tested for impairment annually, or earlier when an impairment indicator occurs. As of statement of financial position dates, only the development costs of C-Cathez under “Development costs”
Property, plant and equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment is stated at cost, net of accumulated depreciation and/or accumulated impairment losses, if any. Repair and maintenance costs are recognized in the income statement as incurred. Depreciation is calculated on a straight-line basis over the estimated useful life of the asset as follows: • Land and buildings: 15 to 20 years • Plant and equipment: 5 to 15 years • Laboratory equipment: 3 to 5 years • Office furniture: 3 to 10 years • Leasehold improvements: based on remaining duration of office building lease • Right-of-use An item of property, plant and equipment and any significant part initially recognized is derecognized upon disposal or when no future economic benefits are expected from its use or disposal. Any gain or loss arising on derecognition of the asset (calculated as the difference between the net disposal proceeds and the carrying amount of the asset) is included in the income statement when the asset is derecognized. The assets’ residual values, useful lives and methods of depreciation are reviewed at each financial year end, and adjusted prospectively, if applicable.
Leases	LEASES The determination of whether an arrangement is, or contains, a lease is based on the substance of the arrangement at inception date whether fulfilment of the arrangement is dependent on the use of a specific asset or assets, or the arrangement conveys a right to use the asset. The Group leases various offices, facilities, cars and IT-equipment. Leases are recognized as a right-of-use asset, presented under “Property, Plant and Equipment”, and a corresponding liability at the date at which the leased asset is available for use by the Group. Each lease payment is allocated between the liability and finance cost. The finance cost is charged to profit or loss over the lease period so as to produce a constant periodic rate of interest on the remaining balance of the liability for each period. The right-of-use asset is depreciated over the shorter of the asset’s useful life and the lease term on a straight-line basis. Assets and liabilities arising from a lease are initially measured on a present value basis. Lease liabilities include the net present value of the following lease payments: • Fixed payments (including in-substance • Variable lease payment that are based on an index or a rate; • Amounts expected to be payable by the lessee under residual value guarantees; • The exercise price of a purchase option if the lessee is reasonably certain to exercise that option; and • Payments of penalties for terminating the lease, if the lease term reflects the lessee exercising that option. The lease term covers the non-cancellable (a) Periods covered by an option to extend the lease if the Group is reasonably certain to exercise that option; and (b) Periods covered by an option to terminate the lease if the Group is reasonably certain not to exercise that option. The lease payments are discounted using the interest rate implicit in the lease. If that rate cannot be determined, the lessee’s incremental borrowing rate is used, being the rate that the lessee would have to pay to borrow the funds necessary to obtain an asset of similar value in a similar economic environment with similar terms and conditions. Right-of-use • The amount of the initial measurement of lease liability; • Any lease payments made at or before the commencement date less any lease incentives received; • Any initial direct costs; and • Restoration costs. Payments associated with short-term leases and leases of low-value Low-value IT-equipment. Until September 2022, the Group subleased some office space it leases from a head lessor. In its capacity as intermediate lessor, the Group assesses whether the sublease is a finance or operating lease in the context of the right-of-use right-of-use right-of-use From time to time, the Group may enter into sale and leaseback transactions. When a sale occurs, both the seller-lessee and the buyer-lessor account for the leaseback in the same manner as any other lease. Specifically, the seller-lessee recognizes a lease liability and right-of-use low-value
Impairment of non-financial assets	IMPAIRMENT OF NON-FINANCIAL The Group assesses at each reporting date whether there is an indication that an asset may be impaired, unless there are indications of impairment at other points throughout the period. If any indication exists, or when annual impairment testing for an asset is required, the Group estimates the asset’s recoverable amount. An asset’s recoverable amount is the higher of an asset’s or cash-generating unit’s (CGU) fair value less costs to sell and its value in use and is determined for an individual asset, unless the asset does not generate cash inflows that are largely independent of those from other assets or group of assets. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax Where the carrying amount of an asset or CGU exceeds its recoverable amount, an impairment loss is immediately recognized as an expense and the asset carrying value is written down to its recoverable amount. An assessment is made at each reporting date as to whether there is any indication that previously recognized impairment losses may no longer exist or may have decreased. If such indication exists, the Group estimates the asset’s or cash-generating unit’s recoverable amount. A previously recognized impairment loss is reversed only if there has been a change in the assumptions used to determine the asset’s recoverable amount since the last impairment loss was recognized. The reversal is limited so that the carrying amount of the asset does not exceed its recoverable amount, nor exceed the carrying amount that would have been determined, net of depreciation, had no impairment loss been recognized for the asset in prior years. Such reversal is recognized in the income statement unless the asset is carried at a revalued amount, in which case the reversal is treated as a revaluation increase. An impairment loss recognized on goodwill is however not reversed in a subsequent period. As of the statement of financial position dates, the Group has two cash-generating units which consist of the development and commercialization activities on: • CYAD products candidate series based on CAR T technology, for the immune-oncology segment; and • C-Cath ez Indicators of impairment used by the Group are the preclinical and clinical results obtained with the technology.
Cash and cash equivalents	CASH AND CASH EQUIVALENTS Cash and cash equivalents in the statement of financial position comprise cash at banks and on hand and very short-term deposits with an original maturity of three months or less. Cash and cash equivalents are carried in the statement of financial position at their nominal value.
Financial assets	FINANCIAL ASSETS Classification The Group classifies its financial assets in accordance with IFRS 9 categories for measurement purposes. The classification depends on the purpose for which the financial assets were acquired. Management determines the classification of its financial assets at initial recognition. ‘Amortized cost’ measurement category refers to loans and receivables which are non-derivative non-current “(non-) “(non-) (non-) Initial recognition and measurement All financial assets are recognized initially at fair value plus or minus, in the case of a financial asset not at fair value through profit or loss, directly attributable transaction costs. Subsequent measurement After initial measurement, financial assets are subsequently measured at amortized cost using the effective interest rate method (EIR), less impairment. Amortized cost is calculated by taking into account any discount or premium on acquisition and fee or costs that are an integral part of the EIR. The EIR amortization is included in finance income in the income statement under “Financial income”. The losses arising from impairment are recognized in the income statement under “Other expenses”. Impairment of financial assets In relation to the impairment of financial assets, IFRS 9 requires an expected credit loss model. The expected credit loss model requires the Group to account for expected credit losses and changes in those expected credit losses at each reporting date to reflect changes in credit risk since initial recognition of the financial assets. In other words, it is no longer necessary for a credit event to have occurred before credit losses are recognized. The Group considers there is no significant additional credit risk related to this receivable, which would not have been captured by the discounting effect, both at inception of the receivable and at the reporting date. As such, no additional ECL allowance has been recognized for this financial asset or any other financial asset. Financial assets carried at amortized cost For financial assets carried at amortized cost the Group first assesses individually whether objective evidence of impairment exists individually for financial assets that are individually significant, or collectively for financial assets that are not individually significant. If the Group determines that no objective evidence of impairment exists for an individually assessed financial asset, it includes the asset in a group of financial assets with similar credit risk characteristics and collectively assesses them for impairment. Assets that are individually assessed for impairment and for which an impairment loss is, or continues to be, recognized are not included in a collective assessment of impairment. If there is objective evidence that an impairment loss has been incurred, the amount of the loss is measured as the difference between the asset’s carrying amount and the present value of estimated future cash flows. The present value of the estimated future cash flows is discounted at the financial assets’ original effective interest rate. If a loan has a variable interest rate, the discount rate for measuring any impairment loss is the current effective interest rate. The carrying amount of the asset is reduced through the use of an allowance account and the amount of the loss is recognized in the income statement under “Other expenses”. Interest income continues to be accrued on the reduced carrying amount and is accrued using the rate of interest used to discount the future cash flows for the purpose of measuring the impairment loss. The interest income is recorded as part of finance income in the income statement under “Financial income”. Loans together with the associated allowance are written off when there is no realistic prospect of future recovery. If, in a subsequent year, the amount of the estimated impairment loss increases or decreases because of an event occurring after the impairment was recognized, the previously recognized impairment loss is increased or reduced by adjusting the allowance account. If a future write-off
Financial liabilities	FINANCIAL LIABILITIES Classification The Group’s financial liabilities include “bank loans”, “lease liabilities”, “recoverable cash advances”, “contingent consideration and other financial liabilities”, “trade payables” and relevant financial liabilities within “Other (non-) The Group classifies and measures its financial liabilities at ‘amortized cost’ using the effective interest method, except “contingent consideration and other financial liabilities” which are classified and measured at ‘fair value through profit or loss’. Initial recognition and measurement Financial liabilities are initially measured at fair value. Transactions costs that are directly attributable to the acquisition or issue of financial liabilities are added or deducted from the fair value of the financial liabilities, as appropriate, on initial recognition. Subsequent measurement The subsequent measurement of financial liabilities depends on their classification as explained above. In particular: Contingent consideration The contingent consideration and other financial liabilities are recognized and measured at fair value at the acquisition date. After initial recognition, contingent consideration arrangements that are classified as liabilities are re-measured Details regarding the valuation of the contingent consideration are disclosed in note 23. Recoverable cash advances Recoverable cash advances granted by the Walloon Region are subsequently measured at amortized cost using the cumulative catch-up Trade payables and other payables After initial recognition, trade payables and other payables are measured at amortized cost using the effective interest method. Loans and borrowings After initial recognition, interest bearing loans and borrowings are subsequently measured at amortized cost using the effective interest rate method. Gains and losses are recognized in the income statement when the liabilities are derecognized. Derecognition A financial liability is derecognized when the obligation under the liability is discharged or cancelled or expires. When an existing financial liability is replaced by another from the same lender on substantially different terms, or the terms of an existing liability are substantially modified, such an exchange or modification is treated as a derecognition of the original liability and the recognition of a new liability, and the difference in the respective carrying amounts is recognized in the income statement under “Change in fair value of contingent consideration” or “Other expenses”.
Provisions	PROVISIONS Provisions are recognized when the Group has a present obligation (legal or constructive) as a result of a past event, it is probable that an outflow of resources embodying economic benefits will be required to settle the obligation and a reliable estimate can be made of the amount of the obligation. Where the Group expects some or all of a provision to be reimbursed, for example under an insurance contract, the reimbursement is recognized as a separate asset but only when the reimbursement is virtually certain. The expense relating to any provision is presented in the income statement net of any reimbursement. If the effect of the time value of money is material, provisions are discounted using a current pre-tax
Employee benefits	Employee benefits Post-employment plan The Group operates a pension plan which requires defined contributions (DC) to be funded by the Group externally at a third-party insurance company. Under Belgian law, an employer must guarantee a minimum rate of return on the Group’s contributions and thus it is treated as defined benefit plan under IAS 19. Therefore, any pension plan (including DC plans) organized in Belgium is treated as defined benefit plans under IAS 19. At the statement of financial position dates, the minimum rates of return guaranteed by the Group are as follows, in accordance with the law of 18 December 2015: • 1.75% for the employer’s contributions paid as from 1 January 2016 (variable rate based on Governmental bond OLO rates, with a minimum of 1.75% and a maximum of 3.75%); • 3.25% (fixed rate) for the employer’s contributions paid until 31 December 2015. The cost of providing benefits is determined using the projected unit credit (PUC) method, with actuarial valuations being carried out at the end of each annual reporting period, with the assistance of an independent actuarial firm. The liability recognized in the statement of financial position in respect of the pension plans is the present value of the defined benefit obligation at the end of the reporting period less the fair value of plan assets. The present value of the defined benefit obligation is determined by discounting the estimated future cash outflows using interest rates of high-quality corporate bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity approximating to the terms of the related pension obligation. The current service cost of the defined benefit plan, recognized in the income statement as part of the operating costs, reflects the increase in the defined benefit obligation resulting from employee service in the current year, benefit changes, curtailments and settlements. Past-service costs are recognized immediately in the income statement. The net interest cost is calculated by applying the discount rate to the net balance of the defined benefit obligation and the fair value of plan assets. This cost is included in the operating costs in the income statement. Actuarial gains and losses arising from experience adjustments and changes in actuarial assumptions are charged or credited to other comprehensive income in the period in which they arise. Short-term benefits Short-term employee benefits are those expected to be settled wholly before twelve months after the end of the annual reporting period during which employee services are rendered, but do not include termination benefits such as wages, salaries, profit-sharing and bonuses and non-monetary The undiscounted amount of the benefits expected to be paid in respect of services rendered by employees in an accounting period is recognized in that period. The expected cost of short-term compensated absences is recognized as the employees render services that increase their entitlement or, in the case of non-accumulating Share-based payments Certain employees, managers and members of the Board of Directors of the Group receive remuneration, as compensation for services rendered, in the form of share-based payments which are “equity-settled”. Measurement The cost of equity-settled share-based payments is measured by reference to the fair value at the date on which they are granted. The fair value is determined by using an appropriate pricing model, further details are given in note 16. Recognition The cost of equity-settled share-based payments is recorded as an expense, together with a corresponding increase in equity, over the period in which the service conditions are fulfilled. The cumulative expense recognized for equity-settled transactions at each reporting date until the vesting date reflects the extent to which the vesting period has expired and the Group’s best estimate of the number of equity instruments that will ultimately vest. Modification Where the terms of an equity-settled transaction award are modified, the minimum expense recognized is the expense as if the terms had not been modified, if the original terms of the award were met. An additional expense is recognized for any modification that increases the total fair value of the share-based payment transaction or is otherwise beneficial to the employee as measured at the date of modification. The incremental fair value granted is the difference between the fair value of the modified equity instrument and the original equity instrument, both estimated as at the date of the modification. If the modification occurs during the vesting period, the incremental fair value granted is included in the measurement of the amount recognized for services received over the period from the modification date until the date when the modified equity instruments vest, in addition to the amount based on the grant date fair value of the original equity instruments, which is recognized over the remainder of the original vesting period. If the modification occurs after vesting date, the incremental fair value granted is recognized immediately, or over the vesting period if the employee is required to complete an additional period of service before becoming unconditionally entitled to those modified equity instruments. Forfeiture An equity-settled award can be forfeited with the departure of a beneficiary before the end of the vesting period, or cancelled and replaced by a new equity settled award. If a new award is substituted for the cancelled award, and designated as a replacement award on the date that it is granted, the cancelled and new awards are treated as if they were a modification of the original award, as described in the previous paragraph. Cancellation If the cancellation occurs during the vesting period, it is treated as an acceleration of vesting, and the Group recognizes immediately the amount that would otherwise have been recognized for services received over the remainder of the vesting period. If the cancellation occurs after the vesting period, no adjustments will be made to the accounting.
Income taxes	INCOME TAXES Tax is recognized in the income statement, except to the extent that it relates to items recognized in other comprehensive income or directly in equity. In this case, the tax is also recognized in other comprehensive income or directly in equity, respectively.
Deferred tax	Deferred tax Deferred tax is provided using the liability method on temporary differences at the reporting date between the tax bases of assets and liabilities and their carrying amounts for financial reporting purposes. Deferred tax liabilities are recognized for all taxable temporary differences, except: • Where the deferred tax liability arises from the initial recognition of goodwill or of an asset or liability in a transaction that is not a business combination and, at the time of the transaction, affects neither the accounting profit nor taxable profit or loss; • In respect of taxable temporary differences associated with investments in subsidiaries, associates and interests in joint ventures, where the timing of the reversal of the temporary differences can be controlled and it is probable that the temporary differences will not reverse in the foreseeable future. Deferred tax assets are recognized for all deductible temporary differences, carry forward of unused tax credits and unused tax losses (except if the deferred tax asset arises from the initial recognition of an asset or liability in a transaction other than a business combination and that, at the time of the transaction affects neither accounting nor taxable profit or loss), to the extent that it is probable that taxable profit will be available against which the deductible temporary differences, and the carry forward of unused tax credits and unused tax losses can be utilized. The carrying amount of deferred tax assets is reviewed at each reporting date and reduced to the extent that it is not probable that sufficient taxable profit will be available to allow all or part of the deferred tax asset to be utilized. Unrecognized deferred tax assets are reassessed at each reporting date and are recognized to the extent that it has become probable that future taxable profits will allow the deferred tax asset to be recovered. Deferred tax assets and liabilities are measured at the tax rates that are expected to apply in the year when the asset is realized or the liability is settled, based on tax rates (and tax laws) that have been enacted or substantively enacted at the reporting date. Deferred tax assets and deferred tax liabilities are offset, if a legally enforceable right exists to set off current tax assets against current income tax liabilities and the deferred taxes relate to income taxes levied by the same taxation authority or either the same taxable entity or different taxable entities where there is an intention to settle the balances on a net basis.
Earnings (loss) per share	EARNINGS (LOSS) PER SHARE The basic net profit/(loss) per share is calculated based on the weighted average number of shares outstanding during the period. The diluted net profit/(loss) per share is calculated based on the weighted average number of shares outstanding including the dilutive effect of potentially dilutive ordinary shares such as warrants and convertible debts. Potentially dilutive ordinary shares should be included in diluted earnings (loss) per share when and only when their conversion to ordinary shares would decrease the net profit per share (or increase net loss per share).
Equity	EQUITY The basic net profit/(loss) per share is calculated based on the weighted average number of shares outstanding during the period. The equity is comprised of the following (further details are given in note 15); • Share capital: Share capital is comprised of the nominal amount of the parent’s ordinary shares. This capital is not distributable in the form of dividends under Belgian Companies and Associations Code. • Share premium: Share premium is comprised of: (1) the amount received attributable to share capital, in excess of the nominal amount of shares issued by the parent company, reduced by; (2) issuance costs directly attributable to the capital increase; and (3) absorption of the accumulated deficit into the share premium, as approved by the Company’s shareholders in accordance with Belgian Companies and Associations Code. • Other reserves: Other reserves are comprised of: (1) Share-base payment reserve; (2) Other equity reserve from conversion of convertible loan in 2013; and (3) Currency Translation differences. • Capital reduction reserve: Capital reduction reserve is comprised of the absorption of historical losses of the Company into the share premium, as approved by the Company’s shareholders in accordance with Belgian Companies and Associations Code. • Accumulated deficit: Accumulated deficit is comprised of cumulative historical losses of the Company.
Assets held for sale	ASSETS HELD FOR SALE In accordance with IFRS 5, Non-current Assets Held for Sale and Discontinued Operations, non-current Non-current held-for-sale non-current Non-current

Operating segment information (

Operating segment information (Tables)	12 Months Ended
	Dec. 31, 2022
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Schedule of Segment Profit by Operating Segment	€‘000 For the year ended December 31, 2020 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time 5 — — 5 Revenue recognized over time — — — — Total Revenue 5 — — 5 Cost of Sales — — — — Gross Profit 5 — — 5 Research & Development expenses (124 ) (21 398 ) — (21 522 ) General & Administrative expenses — — (9 315 ) (9 315 ) Change in fair value of contingent consideration — 9 228 — 9 228 Net Other income/(expenses) (2 ) 4 582 38 4 617 Operating Profit/(Loss) (121 ) (7 589 ) (9 277 ) (16 987 ) Net financial income/(expenses) (33 ) (182 ) (3 ) (217 ) Profit/(Loss) before taxes (154 ) (7 771 ) (9 280 ) (17 204 ) Income Taxes — — — — Profit/(Loss) for the year 2020 (154 ) (7 771 ) (9 280 ) (17 204 ) €‘000 For the year ended December 31, 2021 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time — — — — Revenue recognized over time — — — — Total Revenue — — — — Cost of Sales — — — — Gross Profit — — — — Research & Development expenses (142 ) (20 631 ) — (20 773 ) General & Administrative expenses — — (9 908 ) (9 908 ) Change in fair value of contingent consideration — 847 — 847 Net Other income/(expenses) (108 ) 3 507 44 3 443 Operating Profit/(Loss) (250 ) (16 277 ) (9 864 ) (26 391 ) Net financial income/(expenses) 107 (165 ) (53 ) (111 ) Profit/(Loss) before taxes (143 ) (16 442 ) (9 917 ) (26 502 ) Income Taxes — — (10 ) (10 ) Profit/(Loss) for the year 2021 (143 ) (16 442 ) (9 927 ) (26 512 ) €‘000 For the year ended December 31, 2022 Cardiology Immuno-oncology Corporate Group Total Revenue recognized at a point in time — — — — Revenue recognized over time — — — — Total Revenue — — — — Cost of Sales — — — — Gross Profit — — — — Research & Development expenses (587 ) (18 341 ) — (18 928 ) General & Administrative expenses — — (10 546 ) (10 546 ) Change in fair value of contingent consideration — 14 679 — 14 679 Impairment of Oncology intangible assets — (35 084 ) — (35 084 ) Net Other income/(expenses) (63 ) 9 148 (63 ) 9 022 Operating Profit/(Loss) (650 ) (29 598 ) (10 609 ) (40 857 ) Net financial income/(expenses) (19 ) (132 ) 138 (13 ) Profit/(Loss) before taxes (669 ) (29 730 ) (10 471 ) (40 870 ) Income Taxes — (65 ) — (65 ) Profit/(Loss) for the year 2022 (669 ) (29 795 ) (10 471 ) (40 935 )

Intangible assets (Tables)

Intangible assets (Tables)	12 Months Ended
	Dec. 31, 2022
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Summary of Intangible Assets	The change in intangible assets is broken down as follows, per class of assets: (€‘000) Goodwill In-process Development Patents, Software Total Capitalized costs At January 1, 2021 883 33 678 1 084 13 071 279 48 995 Additions — — — 214 — 214 Divestiture — — — — (16 ) (16 ) At December 31, 2021 883 33 678 1 084 13 285 263 49 193 Additions — — — 876 — 876 Divestiture (239 ) — — (213 ) (165 ) (617 ) At December 31, 2022 644 33 678 1 084 13 948 98 49 452 Accumulated amortization At January 1, 2021 — — (543 ) (12 052 ) (229 ) (12 527 ) Amortization charge — — (67 ) (134 ) (16 ) (217 ) Divestiture — — — — 16 16 At December 31, 2021 — — (610 ) (12 186 ) (229 ) (13 025 ) Amortization charge — — (66 ) (547 ) — (613 ) Divestiture — — — 3 131 134 Impairment (644 ) (33 678 ) — (762 ) — (35 084 ) At December 31, 2022 (644 ) (33 678 ) (676 ) (13 492 ) (98 ) (48 588 ) Net book value Capitalized costs 883 33 678 1 084 13 285 263 49 193 Accumulated amortization — — (610 ) (12 186 ) (229 ) (13 025 ) At December 31, 2021 883 33 678 474 1 099 34 36 168 Capitalized costs 644 33 678 1 084 13 948 98 49 452 Accumulated amortization (644 ) (33 678 ) (676 ) (13 492 ) (98 ) (48 588 ) At December 31, 2022 — — 408 456 — 864
Summary of Probabilities of Success for Products	PoS Phase I Phase I to Phase Phase II to Phase Phase III to BLA BLA to Approval Cumulative PoS CYAD-02 100 % 50 % 28 % 60 % 90 % 7.5 % CYAD-101 100 % 49 % 23 % 43 % 93 % 4.6 % CYAD-211 100 % 50 % 28 % 60 % 90 % 7.5 %

Property, plant and equipment (

Property, plant and equipment (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Changes in Carrying Value of Property, Plant and Equipment	(€’000) Property Equipment Furniture Leasehold Total Capitalized costs At January 1, 2021 3 001 3 563 250 4 032 10 846 Additions 24 388 — 10 422 Disposals — (192 ) — — (192 ) Currency translation adjustments — 1 — 15 16 At December 31, 2021 3 025 3 760 250 4 057 11 092 Additions 146 116 15 — 277 Disposals (3 171 ) (2 180 ) (45 ) (2 903 ) (8 299 ) Currency translation adjustments — 1 — 11 12 Transfers to Assets held for sale — (421 ) (220 ) (989 ) (1 630 ) At December 31, 2022 — 1 276 — 176 1 452 Accumulated depreciation: At January 1, 2021 (827 ) (2 625 ) (214 ) (3 061 ) (6 727 ) Depreciation charge (454 ) (512 ) (24 ) (313 ) (1 303 ) Disposals — 191 — — 191 Currency translation adjustments — (2 ) — (3 ) (5 ) At December 31, 2021 (1 281 ) (2 948 ) (238 ) (3 377 ) (7 844 ) Depreciation charge (439 ) (268 ) — (120 ) (827 ) Disposals 1 720 1 834 18 2 575 6 147 Currency translation adjustments — — — (5 ) (5 ) Transfers to Assets held for sale — 414 220 751 1 385 At December 31, 2022 — (968 ) — (176 ) (1 144 ) Net book value Capitalized costs 3 025 3 760 250 4 057 11 092 Accumulated depreciation (1 281 ) (2 948 ) (238 ) (3 377 ) (7 844 ) At December 31, 2021 1 744 812 12 680 3 248 Capitalized costs — 1 276 — 176 1 452 Accumulated depreciation — (968 ) — (176 ) (1 144 ) At December 31, 2022 — 309 — — 309

Non-Current Trade Receivables A

Non-Current Trade Receivables And Other Non-Current Assets (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Detailed Information About Non-current Trade Receivables	(€‘000) As at December 31, 2022 2021 Non-current — 2 209 Total Non-current — 2 209
Summary of Other Non-current Assets	(€‘000) As at December 31, 2022 2021 R&D Tax credit receivable 3 454 3 764 Total Non-current 3 454 3 764 Deposits 264 262 Total Other non-current 264 262

Trade, Other Receivables and _2

Trade, Other Receivables and Other assets (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Trade, Other Receivables and Other assets	(€‘000) As at December 31, 2022 2021 Trade receivables 909 203 Advance deposits 209 246 Net Investment in Lease — 219 Total Trade and Other receivables 1 118 668 Current Grant receivables (RCAs) — 1 121 Current Grant receivables (Others) — 274 Total Current Grant receivables — 1 395 Prepaid expenses 667 1 688 VAT receivable 316 483 Income and other tax receivables 34 40 Total Other current assets 1 017 2 211 Total Trade receivables, advances and other current assets 2 135 4 274

Cash and Cash Equivalents (Tabl

Cash and Cash Equivalents (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Cash and Cash Equivalents	(€‘000) As at December 31, 2022 2021 Cash at bank and on hand 12 445 30 018 Total 12 445 30 018

Investment in Subsidiaries (Tab

Investment in Subsidiaries (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Consolidated Subsidiaries	The consolidation scope of the Group is as follows, for both current and comparative years presented in these year-end Name Country of Nature of Proportion of shares directly held by parent Proportion of Proportion of non-controlling Celyad SA BE Biopharma Parent company Celyad Inc US Biopharma 100 % 100 % 0 % CorQuest Medical Inc US Medical Device 100 % 100 % 0 % Biological Manufacturing Services SA BE Manufacturing 100 % 100 % 0 %

Share Capital (Tables)

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Share Capital Issued	The number of shares issued is expressed in units. As at December 31, 2022 2021 Total number of issued and outstanding shares 22 593 956 22 593 956 Total share capital (€‘000) 78 585 78 585
Summary of Share Issuances Occurred Since the Incorporation of the Company	The following share issuances occurred since the incorporation of the Company: Category Transaction date Description # of shares Par Class A shares 24 July 2007 Company incorporation 409 375 0.15 Class A shares 31 August 2007 Contribution in kind (upfront fee Mayo License) 261 732 36.30 Class B shares 23 December 2008 Capital increase (Round B) 137 150 35.36 Class B shares 23 December 2008 Contribution in kind (Loan B) 67 502 35.36 Class B shares 28 October 2010 Contribution in cash 21 000 22.44 Class B shares 28 October 2010 Contribution in kind (Loan C) 92 068 35.36 Class B shares 28 October 2010 Contribution in kind (Loan D) 57 095 35.36 Class B shares 28 October 2010 Contribution in cash 73 793 35.36 Class B shares 28 October 2010 Exercise of warrants 12 300 22.44 Class B shares 28 October 2010 Contribution in kind (Mayo receivable) 69 455 44.20 Class B shares 28 October 2010 Contribution in cash 9 048 44.20 Class B shares 31 May 2013 Contribution in kind (Loan E) 118 365 38.39 Class B shares 31 May 2013 Contribution in kind (Loan F) 56 936 38.39 Class B shares 31 May 2013 Contribution in kind (Loan G) 654 301 4.52 Class B shares 31 May 2013 Contribution in kind (Loan H) 75 755 30.71 Class B shares 31 May 2013 Contribution in cash 219 016 31.96 Class B shares 4 June 2013 Conversion of warrants 2 409 176 0.01 Ordinary shares 11 June 2013 Conversion of Class A and Class B shares in ordinary shares 4 744 067 — Ordinary shares 5 July 2013 Initial Public Offering 1 381 500 16.65 Ordinary shares 15 July 2013 Exercise of over-allotment option 207 225 16.65 Ordinary shares 31 January 2014 Exercise of warrants issued in September 2008 5 966 22.44 Ordinary shares 31 January 2014 Exercise of warrants issued in May 2010 333 22.44 Ordinary shares 31 January 2014 Exercise of warrants issued in January 2013 120 000 4.52 Ordinary shares 30 April 2014 Exercise of warrants issued in September 2008 2 366 22.44 Ordinary shares 16 June 2014 Capital increase 284 090 44.00 Ordinary shares 30 June 2014 Capital increase 284 090 44.00 Ordinary shares 4 August 2014 Exercise of warrants issued in September 2008 5 000 22.44 Ordinary shares 4 August 2014 Exercise of warrants issued in October 2010 750 35.36 Ordinary shares 3 November 2014 Exercise of warrants issued in September 2008 5 000 22.44 Ordinary shares 21 January 2015 Contribution in kind (Celdara Medical LLC) 93 087 37.08 Ordinary shares 7 February 2015 Exercise of warrant issued in May 2010 333 22.44 Ordinary shares 3 March 2015 Capital increase 713 380 44.50 Ordinary shares 11 May 2015 Exercise of warrant issued in May 2010 500 22.44 Ordinary shares 24 June 2015 Capital increase 1 460 000 60.25 Ordinary shares 4 August 2015 Exercise of warrant issued in May 2010 666 22.44 Ordinary shares 4 August 2015 Exercise of warrant issued in October 2010 5 250 35.36 Ordinary shares 1 February 2017 Exercise of warrant issued in May 2013 207 250 2.64 Ordinary shares 2 May 2017 Exercise of warrant issued in May 2013 4 900 2.64 Ordinary shares 1 August 2017 Exercise of warrant issued in May 2013 7 950 2.64 Ordinary shares 23 August 2017 Contribution in kind (Celdara Medical LLC) 328 275 32.35 Ordinary shares 9 November 2017 Exercise of warrant issued in May 2013 5 000 2.64 Ordinary shares 9 November 2017 Exercise of warrant issued in October 2010 866 35.36 Ordinary shares 7 February 2018 Exercise of warrant issued in May 2013 4 500 2.64 Ordinary shares 22 May 2018 Capital increase 2 070 000 22.29 Ordinary shares 16 September 2019 Capital increase 2 000 000 9.08 Ordinary shares 8 January 2021 Capital increase 262 812 4.94 Ordinary shares 29 March 2021 Capital increase 200 000 6.19 Ordinary shares 9 April 2021 Capital increase 300 000 5.83 Ordinary shares 29 April 2021 Capital increase 300 000 5.23 Ordinary shares 21 May 2021 Capital increase 182 000 4.58 Ordinary shares 14 June 2021 Capital increase 6 800 4.98 Ordinary shares 28 June 2021 Capital increase 300 000 4.46 Ordinary shares 22 July 2021 Capital increase 300 000 3.46 Ordinary shares 20 October 2021 Capital increase 300 000 3.38 Ordinary shares 8 December 2021 Capital increase 6 500 000 4.44 (€000) Nature of the transactions Share Share Capital Other Accumulated Number of Balance as at January 1, 2021 48 513 43 349 191 213 30 958 (283 039 ) 13 942 344 Reduction of share premium by absorption of losses — (43 349 ) 43 349 — — — Capital increase 30 072 8 900 — — — 8 651 612 Transaction costs associated with capital increases — (2 583 ) — — — — Loss for the period — — — — (26 512 ) — Share Based Payment — — — 2 172 — — Currency Translation differences — — — 42 — — Remeasurements of defined benefit obligation — — — — 554 — Balance as at December 31, 2021 78 585 6 317 234 562 33 172 (308 997 ) 22 593 956 Loss for the period — — — — (40 935 ) — Share Based Payment — — — 1 624 — — Currency Translation differences — — — 4 — — Remeasurements of defined benefit obligation — — — — (15 ) — Balance as at December 31, 2022 78 585 6 317 234 562 34 800 (349 947 ) 22 593 956

Share-Based Payments (Tables)

Share-Based Payments (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Changes in Number of Warrants Outstanding	Changes in the number of warrants outstanding and their related weighted average exercise prices are as follows: 2022 2021 Weighted average Number of warrants Weighted average Number of warrants Outstanding as of January 1, 13.06 2 136 556 17.00 1 488 006 Granted 1.82 594 450 5.29 760 800 Forfeited 2.74 (109 108 ) 4.94 (77 250 ) Exercised — — — — Expired 15.80 (282 252 ) 10.23 (35 000 ) At December 31, 8.36 2 339 646 13.06 2 136 556
Summary of Warrants Outstanding	Warrants outstanding at the end of the year have the following expiry date and exercise price: Warrant plan issuance date Vesting date Expiry date Number of warrants Number of warrants Exercise 06 May 2013 06 May 2016 06 May 2023 2 500 2 500 2.64 05 May 2014 05 May 2017 05 May 2024 35 698 35 698 38.25 05 November 2015 05 November 2018 05 November 2025 79 315 79 315 30.67 08 December 2016 08 December 2019 08 December 2021 7 500 7 500 32.04 29 June 2017 29 June 2020 31 July 2022 — 282 251 31.34 26 October 2018 26 October 2021 31 December 2023 365 817 365 817 18.26 25 October 2019 25 October 2022 31 December 2024 529 950 549 842 7.13 11 December 2020 10 December 2023 31 December 2027 498 883 532 133 6.24 11 October 2021 11 October 2024 31 December 2028 819 983 281 500 2.38 2 339 646 2 136 556
Summary of Fair Value of Warrants Determined At Grant Date	The fair value of the warrants has been determined at grant date based Warrants issued on 06 May 05 May 05 Nov. 08 Dec. 29 Jun. 26 Oct. 25 Oct. 10 Dec. 11 Oct. Total Number of warrants issued 266 241 100 000 466 000 100 000 520 000 700 000 939 500 561 525 777 050 4 430 316 Number of warrants accepted 253 150 94 400 353 550 45 000 334 400 426 050 602 025 557 050 874 200 3 539 825 Number of warrants not fully — — — — — — 289 834 498 883 819 983 1 608 700 Average exercise price (in €) 2.64 38.25 30.67 32.04 31.34 18.26 7.13 6.24 2.38 Expected share value 39.55 % 67.73 % 60.53 % 61.03 % 60.61 % 58.82 % 59.14 % 58.84 % 56.86 % Risk-free interest rate 2.06 % 1.09 % 0.26 % -0.40 % -0.23 % -0.06 % -0.38 % -0.66 % -0.30 % Average fair value (in €) 12.44 25.19 20.04 16.18 15.58 8.90 3.99 3.45 1.36 Weighted average remaining 0.34 1.34 2.84 (1.07 ) (0.51 ) 0.82 1.81 4.94 5.78

Post-Employment Benefits (Table

Post-Employment Benefits (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Pension Obligations	(€’000) As at December 31, 2022 2021 Pension obligations 13 53 Total 13 53
Summary of Defined Benefit Amounts Recognized in the Statement of Financial Position	The amounts recognized in the statement of financial position are determined as follows: (€‘000) As at December 31, 2022 2021 Present value of funded obligations 2 568 2 408 Fair value of plan assets (2 555 ) (2 355 ) Deficit of funded plans 13 53 Total deficit of defined benefit pension plans 13 53 Liability in the statement of financial position 13 53
Summary of Change in Defined Benefit Liability	The change in the defined benefit liability over the year is as (€‘000) Present value Fair value of Total At January 1, 2021 2 747 2 133 614 Current service cost 206 — 206 Interest expense/(income) 18 49 (31 ) 2 971 2 182 789 Remeasurements - Actuarial (Gain)/loss due to change in actuarial assumptions (17 ) — (17 ) - Actuarial (Gain)/loss due to change in demographic assumptions 36 — 36 - Actuarial (Gain)/Loss due to experience (537 ) — (537 ) (518 ) — (518 ) Employer contributions: — 218 (218 ) Benefits Paid (45 ) (45 ) — At December 31, 2021 2 408 2 355 53 At January 1, 2022 2 408 2 355 53 Current service cost 169 — 169 Interest expense/(income) 26 23 3 2 603 2 378 225 Remeasurements - Actuarial (Gain)/loss due to change in actuarial assumptions (13 ) — (13 ) - Actuarial (Gain)/Loss due to experience 26 — 26 - Curtailment in year (3 ) — (3 ) 10 — 10 Employer contributions: — 222 (222 ) Benefits Paid (45 ) (45 ) — At December 31, 2022 2 568 2 555 13
Summary of Income Statement Charge Included in Operating Profit for Post- employment Benefits	The income statement charge included in operating profit for post-employment benefits amount to: (€‘000) 2022 2021 2020 Current service cost 169 206 233 Interest expense on DBO 26 18 30 Expected return on plan assets (24 ) (13 ) (24 ) Amount recognized on curtailment/settlement (3 ) — — Net periodic pension cost 168 211 239
Summary of Remeasurements Included in Other Comprehensive Loss	The re-measurements (€‘000) 2022 2021 2020 Effect of changes in actuarial assumptions (13 ) (17 ) 187 Effect of experience adjustments 26 (537 ) 24 Effect of changes in demographic assumptions — 36 — (Gain)/Loss on assets for the year 2 (36 ) (14 ) Remeasurement of post-employment benefit obligations 15 (554 ) 197

Other Reserves (Tables)

Other Reserves (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Information on Other Reserves	(€’000 ) Share based Other equity Currency Total Balance as at January 1, 2021 15 803 16 631 (1 476 ) 30 958 Vested share-based payments 2 172 — — 2 172 Currency Translation differences subsidiaries — — 42 42 Balance as at December 31, 2021 17 975 16 631 (1 434 ) 33 172 Vested share-based payments 1 624 — — 1 624 Currency Translation differences subsidiaries — — 4 4 Balance as at December 31, 2022 19 599 16 631 (1 430 ) 34 800

Recoverable Cash Advances (Tabl

Recoverable Cash Advances (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Current and Non-current Portion Financial Liabilities	(€‘000) As at December 31, 2022 2021 Non-Current 5 851 4 220 Non-Current 4 584 5 851 Current portion as at January 1, 362 371 Current portion as at December 31, 437 362 Total Recoverable Cash Advances as at January 1, 6 213 4 590 Total Recoverable Cash Advances as at December 31, 5 021 6 213
Summary of Information on Other Outstanding Advances	(in €‘000) Amounts received for the years Amounts to be received As at Id Project Contractual Prior 2021 2022 Cumulated 2023 and Amounts Status Amount 5915 C-Cathez 910 910 — — 910 — — Exploitation 740 6633 C-Cathez 1 020 1 020 — — 1 020 — — Exploitation 306 7027 C-Cathez 2 500 2 500 — — 2 500 — — Exploitation 675 7502 CAR-T Cell 2 000 2 000 — — 2 000 — — Exploitation 100 7685 THINK 3 496 3 496 — — 3 496 — — Exploitation 105 8087 CYAD01 - Deplethink 2 492 2 070 — — 2 070 — 421 Exploitation — 8088 CYAD02 - Cycle1 3 538 1 500 746 222 2 468 — 1 071 Exploitation — 1910028 CwalityCAR 2 102 749 199 1 113 2 061 — 41 Exploitation — 8212 CYAD-101 3 300 825 1 370 775 2 970 330 — Research — 8436 Immunicy 3 394 1 697 — 348 2 045 1 349 — Research — 8516 New engagers 1 095 — 274 — 274 821 — Research — Total 25 847 16 767 2 589 2 458 21 814 2 500 1 533 1 926
Summary of Certain Terms and Conditions for the Recoverable Cash Advances	The table below summarizes, in addition to the specific characteristics described above, certain terms and conditions for the recoverable cash advances: Contract number Research phase Percentage Turnover- Turnover-independent Interest Amounts (€’000) 5915 01/08/08-30/04/11 70 % 5.00 % €40k in 2012 and €70k each year after N/A 10% with a minimum of 100/Y 6633 01/05/11-30/11/12 60 % 0.27 % From €10k to €51k starting in 2013 until 30% of advance is reached Starting 01/06/13 N/A 7027 01/11/12-31/10/14 50 % 0.33 % From €25k to €125k starting in 2015 until 30% of advance is reached Starting 01/01/15 N/A 7502 01/12/15-30/11/18 45 % 0.19 % From €20k to €50k starting in 2019 until 30% is reached. Starting 01/12/19 N/A 7685 01/01/17-31/12/19 45 % 0.33 % From €35k to €70k starting in 2019 until 30% is reached. Starting 01/01/21 N/A 8087 01/05/19- 30/06/21 45 % 0.22 % From €20k to €61k starting in 2022 until 30% is reached Starting 01/07/22 N/A 8088 01/05/19- 31/12/21 45 % 0.21 % From €25k to €74k starting in 2022 until 30% is reached Starting 01/01/22 N/A 1910028 06/06/19- 05/06/22 45 % 0.01 % From €21k to €41k starting in 2022 until 30% is reached Starting 06/06/22 N/A 8212 01/01/20- 30/06/23 45 % 0.46 % From €33k to €99k starting in 2024 until 30% is reached Starting 01/07/23 N/A 8436 01/11/20- 31/12/23 45 % 0.32 % From €34k to €102k starting in 2024 until 30% is reached Starting 01/01/24 N/A 8516 01/04/21-31/03/23 45 % 0.10 % From €11k to 33k starting in 2024 until 30% is reached Starting 01/04/23 N/A

Due Dates of the Financial Li_2

Due Dates of the Financial Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Aggregate Information Material Contractual Obligations and Payments Due	Financial liabilities reported as at December 31, 2022: (€‘000) Total Less than one One to three Three to five More than five As at December 31, 2022 Lease liabilities (undiscounted) 259 141 118 — — Pension obligations 13 — — — 13 Advances repayable (current and non-current) 5 021 437 640 637 3 307 Total financial liabilities 5 293 578 758 637 3 320 Financial liabilities reported as at December 31, 2021: (€‘000) Total Less than one One to three Three to five More than five As at December 31, 2021 Lease liabilities (undiscounted) 2 965 1 057 1 431 477 — Pension obligations 53 — — — 53 Advances repayable (current and non-current) 6 213 362 616 740 4 495 Total financial liabilities 9 231 1 419 2 047 1 217 4 548

Other Non-Current Liabilities (

Other Non-Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Schedule of Other Non-Current Liabilities	(€‘000) As at December 31, 2022 2021 Onerous contracts - non-current 124 — Other non-current 134 164 Total Other non-current 258 164

Trade Payables and Other Curr_2

Trade Payables and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Trade Payables and Other Current Liabilities	(€‘000) As at December 31, 2022 2021 Total Trade payables 4 752 6 611 Social security 94 332 Payroll accruals 1 294 1 798 Onerous contracts - current liabilities 2 113 388 Other current grant liabilities 889 1 096 Other current liabilities 710 2 338 Total Other current liabilities 5 100 5 952 Total Trade payables and other current liabilities 9 852 12 563

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Carrying and Fair Values of Financial Instruments that are not Carried at Fair Value	The carrying and fair values of financial instruments that are not reported at fair value in the consolidated financial statements were as (€‘000) As at December 31, 2022 Financial assets at Fair value Financial Assets (‘Amortized cost’ category) within: Non-current — — Other non-current 264 264 Trade receivables and other current assets 1 118 1 118 Short-term investments — — Cash and cash equivalents 12 445 12 445 Total 13 827 13 827 For the above-mentioned financial assets, the carrying amount as per December 31, 2022, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2022 Financial liabilities at Fair value Financial Liabilities (‘Financial liabilities at amortized cost’ category) within: Lease liabilities 255 255 RCAs liability 5 021 5 021 Trade payables 4 752 4 752 Total 10 028 10 028 For the above-mentioned financial liabilities, the carrying amount as per December 31, 2022, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2021 Financial assets at Fair value Financial Assets (‘Amortized cost’ category) within: Non-current 2 209 2 209 Other non-current 262 262 Trade receivables and other current assets 668 668 Short-term investments — — Cash and cash equivalents 30 018 30 018 Total 33 157 33 157 For the above-mentioned financial assets, the carrying amount as per December 31, 2021, is a reasonable approximation of their fair value. (€‘000) As at December 31, 2021 Financial liabilities at Fair value Financial Liabilities (‘Financial liabilities at amortized cost’ category) within: Finance lease liabilities 2 632 2 632 RCAs liability 6 213 6 213 Trade payables and other current liabilities 6 611 6 611 Total 15 456 15 456 For the above-mentioned financial liabilities, the carrying amount as per December 31, 2021, is a reasonable approximation of their fair value.
Schedule of Financial Assets and Liabilities Measured at Fair Value	Contingent consideration and other financial liabilities are reported at fair value in the statement of financial position using Level 3 fair value measurements for which the Group developed unobservable inputs. (€‘000) As at December 31, 2022 Level I Level II Level III Total Liabilities Contingent consideration and other financial liabilities — — — — Total Liabilities — — — — (€‘000) As at December 31, 2021 Level I Level II Level III Total Liabilities Contingent consideration and other financial liabilities — — 14 679 14 679 Total Liabilities — — 14 679 14 679
Contingent Consideration and Other Financial Liabilities	The change in the balance is detailed as follows: (€‘000) For the year ended 2022 2021 Opening balance Contingent consideration at January 1, 14 679 15 526 Milestone payment — — Fair value adjustment (14 679 ) (847 ) Closing balance Contingent consideration at December 31, — 14 679
Sensitivity Analysis Performed on Main Assumptions	PoS Phase Phase I to Phase Phase II to Phase Phase III to BLA BLA to Cumulative PoS CYAD-02 100 % 50 % 28 % 60 % 90 % 7.5 % CYAD-101 100 % 49 % 23 % 43 % 93 % 4.6 %

Changes in Liabilities Arisin_2

Changes in Liabilities Arising from Financial Activities (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Bank Loans Financial Liability Roll Forward	The change in bank loans balances is detailed as follows: BANK LOANS FINANCIAL LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, — 37 Payments — (37 ) Closing balance at December 31, — —
Summary of Finance Leases Financial Liability Roll Forward	The change in lease liability balances is detailed as follows: LEASES FINANCIAL LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, 2 632 3 602 New leases 170 129 Payments (896 ) (1 099 ) Remeasurement (1 651 ) — Closing balance at December 31, 255 2 632
Summary of Recoverable Cash Advance Liability Roll Forward	The change in recoverable cash advance liability balances is detailed follows RECOVERABLE CASH ADVANCE LIABILITY ROLL FORWARD (€‘000) For the year ended 2022 2021 Opening balance at January 1, 6 213 4 590 Repayments (230 ) (280 ) Proceeds - Liability component 485 1 575 Remeasurement (1 447 ) 328 Closing balance at December 31, 5 021 6 213

Revenues (Tables)

Revenues (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Revenues	(€‘000) For the year ended December 31, 2022 2021 2020 Out-licensing — — — Other revenue — — 5 Total — — 5

Operating Expenses (Tables)

Operating Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Research and Development Expenses	Research and development expenses The following table is a summary of manufacturing expenses, clinical, quality and regulatory expenses and other research and development expenses, which are aggregated and presented as research and development expenses in the Group’s consolidated financial statements. (€‘000) For the year ended December 31, 2022 2021 2020 Employee expenses 9 062 9 475 8 564 Clinical study costs 4 280 4 000 5 555 Preclinical study costs 1 233 2 473 1 976 Depreciation 1 231 1 276 1 511 IP filing and maintenance fees 831 353 230 Rent and utilities 610 670 800 Share-based payments 425 644 927 Process development and scale-up 396 770 1 056 Consulting fees 320 568 372 Travel & Living 126 85 116 Delivery systems — — 47 Others 415 459 369 Total R&D expenses 18 928 20 773 21 522
Summary of General and Administrative Expenses	General and administrative expenses (€‘000) For the year ended December 31, 2022 2021 2020 Employee expenses 3 801 3 575 3 363 Consulting fees 2 870 2 254 1 747 Insurances 1 967 1 642 1 182 Share-based payments 1 199 1 529 1 855 Communication & Marketing 239 434 454 Depreciation 209 243 320 Travel & Living 115 31 91 Rent 109 50 87 Post-employment benefits (55 ) (7 ) 19 Other 92 157 197 Total General and administration 10 546 9 908 9 315

Employee Benefit Expenses (Tabl

Employee Benefit Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Employee Expenses	(€‘000) For the year ended December 31, 2022 2021 2020 Salaries, wages and fees 7 470 7 975 7 139 Executive Committee compensation 3 599 3 115 2 773 Share-based payments 1 624 2 172 2 782 Social security 1 237 1 444 1 487 Post-employment benefits 147 251 263 Hospitalization insurance 226 142 146 Other benefit expense 128 116 138 Total Employee expenses 14 432 15 215 14 727
Summary Of Staff Full Time Equivalent	Staff full time equivalent (“FTE”) For the year ended December 31, 2022 2021 2020 Research & Development 82.6 94.1 81.7 General and Administration 11.0 18.2 16.6 Total Staff FTE 93.6 112.3 98.3

Other Income And Other Expens_2

Other Income And Other Expenses (Table)	12 Months Ended
	Dec. 31, 2022
Other Income And Expenses [Abstract]
Summary of Other Income	Other income (€‘000) For the year ended December 31, 2022 2021 2020 Grant income (RCA’s) 1 137 2 731 2 311 Grant income (Other) 910 1 448 779 Remeasurement of RCA’s 1 447 — 933 R&D tax credit 462 687 657 Gain on sale of CTMU activities 5 187 — — Gain on sales of Property, plant & equipment — — 35 Remeasurement of Leases 169 — — Other 48 43 17 Total Other Income 9 360 4 909 4 731
Summary of Other Expenses	Other expenses (€‘000) For the year ended December 31, 2022 2021 2020 Clinical Development milestone payment — — 69 Remeasurement of RCA’s — 328 — Loss on disposals of Property, plant & equipment 132 1 10 Loss on disposals of Intangible assets 58 — — Amendment fees on license agreement — 1 104 — Other 149 33 35 Total Other Expenses 339 1 466 114

Change In Fair Value Of Conti_2

Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of detailed information about intangible assets [abstract]
Schedule of Change in Fair Value of Contingent Consideration	Change in fair value of contingent consideration (€‘000) For the year ended December 31, 2022 2021 2020 Change in fair value of contingent consideration 14 679 847 9 228 Total Change in fair value of contingent consideration 14 679 847 9 228
Schedule of Impairment of Oncology intangible assets	Impairment of Oncology intangible assets (€‘000) For the year ended December 31, 2022 2021 2020 Impairment of Oncology intangible assets (35 084 ) — — Total Impairment of Oncology intangible assets (35 084 ) — —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Property Plant And Equipment Owned And Leased Assets	(€’000) As at December 31, 2022 2021 Property, Plant and Equipment owned (excluding right-of-use 86 1 033 Right-of-use 223 2 215 Total Property, Plant and Equipment 309 3 248
Summary of Lease Liabilities	The consolidated statements of financial position shows the following amounts relating to leases for which the Group is a lessee: (€’000) Property Vehicles Equipment Total Cost At January 1, 2021 3 001 429 1 491 4 920 Additions 24 67 — 91 Disposals — (41 ) — (41 ) Transfers — — (950 ) (950 ) At December 31, 2021 3 025 454 541 4 020 Additions 146 7 — 153 Disposals (3 171 ) (131 ) — (41 ) At December 31, 2022 — 331 541 872 Accumulated depreciation At January 1, 2021 (827 ) (165 ) (924 ) (1 916 ) Depreciation charge (454 ) (117 ) (309 ) (880 ) Disposals — 41 — 41 Transfers — — 950 950 At December 31, 2021 (1 281 ) (241 ) (283 ) (1 805 ) Depreciation charge (439 ) (105 ) (118 ) (663 ) Disposals 1 721 98 — 1 819 At December 31, 2022 — (248 ) (401 ) (649 ) Net book value Cost 3 025 454 541 4 020 Accumulated depreciation (1 281 ) (241 ) (283 ) (1 805 ) At December 31, 2021 1 744 213 258 2 215 Cost — 331 541 872 Accumulated depreciation — (248 ) (401 ) (649 ) At December 31, 2022 — 83 140 223
Summary of Lease Expense	The consolidated statements of comprehensive loss show the following amounts relating to leases: (€’000) For the 12-month period ended December 31, 2022 2021 2020 Depreciation charge of right-of-use Property 439 454 428 Vehicles 105 76 75 Equipment 118 309 567 Interest on lease liabilities (including in Financial expenses) 1 150 217 259 Interest on sublease receivable (including in Financial income) 1 (11 ) (26 ) (46 ) Variable lease payments not included in the measurement of lease liabilities — — — Remeasurement of Leases (169 ) — — Expenses relating to short-term leases and leases of low-value 126 137 166 Total expenses related to leases 758 1 167 1 449 1 Interests on leases are presented as operating cash flow.
Summary of Cash Outflow For Leases	Total cash outflow for leases (€’000) For the 12-month period ended December 31, 2022 2021 2020 Total cash outflow for leases 1 172 1 453 1 681

Financial Income and Expenses (

Financial Income and Expenses (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Financial Revenues and Expenses	(€’000) For the year ended December 31, 2022 2021 2020 Interest finance leases 150 217 260 Interest on overdrafts and other finance costs 33 21 19 Interest on RCAs 14 17 18 Foreign Exchange differences — — 136 Finance expenses 198 255 434 Finance income on the net investment in lease 11 26 46 Interest income bank account 1 1 5 Foreign Exchange differences 173 5 — Other financial income — 112 166 Finance income 185 144 217 Net Financial result (13 ) (111 ) (217 )

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Group Reports Income Taxes in the Income Statement	The Group reports income taxes in the income statement as detailed below: (€‘000) For the year ended December 31, 2022 2021 2020 Current tax (expense) / income (65 ) (10 ) — Deferred tax (expense) / income — — — Total income tax expense in profit or loss (65 ) (10 ) —
Schedule of Reconciliation Between Effective and Theoretical Tax	The (€‘000) For the year ended December 31, 2022 2021 2020 Loss before tax (40 870 ) (26 502 ) (17 204 ) Permanent differences Tax disallowed expenses 1 248 1 185 1 092 Share-based payment 1 624 2 172 2 782 Nominal tax rate 25.00 % 25.00 % 25.00 % Income tax at nominal tax rate 1 9 500 5 786 3 333 Deferred tax assets not recognized (9 565 ) (5 796 ) (3 333 ) Effective tax expense (65 ) (10 ) — Effective tax rate 0 % 0 % 0 % 1 The difference in foreign tax rate in the US (25.80%) compared to the Belgian rate (25.00%) is not distinctively disclosed in this table due to non-materiality

Deferred Taxes (Tables)

Deferred Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets and liabilities are detailed below by nature of temporary differences for the current year: (€‘000) For the year ended December 31, 2022 Assets Liabilities Net Intangibles assets — (216 ) (216 ) Recoverable cash advances liability 1 226 — 1 226 Contingent consideration liability — — — Employee Benefits liability 3 — 3 Other temporary difference 272 — 272 Tax-losses 78 332 — 78 332 Unrecognized Gross Deferred Tax assets/(liabilities) 79 833 (216 ) 79 617 Netting by tax entity (216 ) 216 — Unrecognized Net Deferred Tax assets/(liabilities) 79 617 — 79 617 (€‘000) For the year ended December 31, 2021 Assets Liabilities Net Intangibles assets — (2 709 ) (2 709 ) Recoverable cash advances liability 1 503 — 1 503 Contingent consideration liability 3 670 — 3 670 Employee Benefits liability 13 — 13 Other temporary difference — (586 ) (586 ) Tax-losses 72 671 — 72 671 Unrecognized Gross Deferred Tax assets/(liabilities) 77 857 (3 295 ) 74 562 Netting by tax entity (3 295 ) 3 295 — Unrecognized Net Deferred Tax assets/(liabilities) 74 562 — 74 562
Schedule of Unrecognized Deferred Tax Asset Balance Roll Forward	The change in the Group’s net deferred tax asset balance is detailed below: UNRECOGNIZED DEFERRED TAX ASSET BALANCE ROLL FORWARD (€‘000) For the year ended 2022 2021 2020 Opening balance at January 1, 74 562 66 208 61 300 Temporary difference creation or reversal (606 ) (1 014 ) (2 981 ) Change in Tax-losses 5 661 8 820 8 064 Change in US tax rate applicable — 548 (176 ) Closing balance at December 31, 79 617 74 562 66 208

Relationships with Related Pa_2

Relationships with Related Parties (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Summary of Remuneration of Key Management Informations	Remuneration of key management Key management consists of the members of t he As at December 31, 2022 2021 2020 Number of Executive Committee members 7 7 6 (€’000) For the year ended 2022 2021 2020 Short term employee benefits [1] 2 294 1 866 1 349 Post employee benefits 53 45 34 Share-based compensation 790 928 1 110 Other employment costs [2] 143 148 110 Management fees 1 200 1 163 1 335 Total benefits 4 480 4 150 3 939 Executive Committee outstanding fees payables 781 844 660 (1) Include salaries, social security, bonuses, lunch vouchers (2) Company cars The increase of the short term employees benefits as of December 31, 2022, include the one-off As at December 31, 2022 2021 2020 Number of warrants granted 489 700 395 000 220 000 Number of warrants lapsed (127 250 ) (30 000 ) (20 000 ) Cumulative outstanding warrants 696 400 921 000 556 000 Exercised warrants — — —
Summary of Transactions with Related Parties	Transactions with non-executive For the year ended December 31, (€‘000) 2022 2021 2020 Share-based compensation 230 337 396 Management fees 382 373 366 Total benefits 612 710 762 Non-executive 93 93 94 As at December 31, 2022 2021 2020 Number of warrants granted 40 000 150 000 80 000 Number of warrants lapsed (60 000 ) — (30 000 ) Number of exercised warrants — — — Cumulative outstanding warrants 230 000 340 000 220 000

Loss per share (Tables)

Loss per share (Tables)	12 Months Ended
	Dec. 31, 2022
Text block [abstract]
Calculation of Earnings (Loss) Per Share	(€’000) As at December 31, 2022 2021 2020 Loss of the year attributable to Equity Holders (40 935 ) (26 512 ) (17 204 ) Weighted average number of shares outstanding 22 593 956 15 604 014 13 942 344 Earnings per share (non-fully (1.81 ) (1.70 ) (1.23 ) Outstanding warrants 2 339 646 2 136 556 1 488 006

The Company - Additional Inform

The Company - Additional Information (Detail) € in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2022 EUR (€)	Dec. 31, 2022 Subsidiaries
Disclosure of detailed information about business combination [abstract]
Number of subsidiaries owned by the entity | Subsidiaries		3
Asset acquisition consideration transferred | €	€ 60

General Information and State_2

General Information and Statement of Compliance - Additional Information (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Cash and cash equivalents	€ 12,445	€ 30,018	€ 17,234	€ 39,338
Short-term investments, classified as cash equivalents	€ 0	€ 0

Accounting Principles - Additio

Accounting Principles - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 Cash_Generating
Disclosure of significant accounting policies [line items]
Exploitation phase period for recoverable cash advances	20 years
Development costs, capitalization period	17 years
Development costs, amortization period	17 years
Number of cash generating units	2
Non-current financial assets, description	‘Amortized cost’ measurement category refers to loans and receivables which are non-derivative financial assets, with fixed or determinable payments that are not quoted in an active market. They are included in current assets, except for maturities greater than 12 months after the end of the reporting period which are classified as non-current assets. This measurement category comprises “cash and cash equivalents”, “short-term investments”, and relevant financial assets within “(non-) current trade and other receivables”, “(non-) current grant receivables” and “other (non-) current assets”.
Sales independent reimbursements equivalent percentage of principal amount	30%
Walloon Region [Member]
Disclosure of significant accounting policies [line items]
Percentage of principal amount	200%
Land and buildings [member]
Disclosure of significant accounting policies [line items]
Depreciation on property, plant and equipment	15 to 20 years
Plant and equipment [member]
Disclosure of significant accounting policies [line items]
Depreciation on property, plant and equipment	5 to 15 years
Laboratory equipment [member]
Disclosure of significant accounting policies [line items]
Depreciation on property, plant and equipment	3 to 5 years
Furniture [member]
Disclosure of significant accounting policies [line items]
Depreciation on property, plant and equipment	3 to 10 years
Top of range [member]
Disclosure of significant accounting policies [line items]
Cash and cash equivalents, original maturity period	3 months
Sales dependant reimbursements percentage	170%
Top of range [member] | Software [member]
Disclosure of significant accounting policies [line items]
Estimated useful lives of software	5 years
Bottom of range [member]
Disclosure of significant accounting policies [line items]
Sales dependant reimbursements percentage	70%
Bottom of range [member] | Software [member]
Disclosure of significant accounting policies [line items]
Estimated useful lives of software	3 years

Risk Management - Additional in

Risk Management - Additional information (Detail) € in Thousands	12 Months Ended
	Dec. 31, 2022 EUR (€)
A1 Percentage Depreciation [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Unrealized foreign (loss) gain	€ 9

Critical Accounting Estimates_2

Critical Accounting Estimates and Judgments - Additional Information (Detail) € in Millions	12 Months Ended
	Dec. 31, 2022 EUR (€)
Disclosure of changes in accounting estimates [abstract]
Repayable recoverable cash advances percentage	30%
Royalty of future sales milestones, percentage	170%
Provision for onerous contracts	€ 2.2

Operating Segment Information -

Operating Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 Segment
Disclosure of operating segments [line items]
Number of operating segments	2

Operating Segment Information_2

Operating Segment Information - Schedule of Segment Profit by Operating Segment (Detail) - EUR (€) € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of operating segments [line items]
Revenue recognized at a point in time				€ 5
Revenue recognized over time				0
Revenue		0	0	5
Cost of Sales
Gross Profit		0	0	5
Research & Development expenses		(18,928)	(20,773)	(21,522)
General & Administrative expenses		(10,546)	(9,908)	(9,315)
Change in fair value of contingent consideration		14,679	847	9,228
Impairment of Oncology intangible assets		(35,084)	0	0
Net Other income/(expenses)		9,022	3,443	4,617
Operating Loss	[1]	(40,857)	(26,391)	(16,987)
Net financial income/(expenses)		(13)	(111)	(217)
Loss before taxes		(40,870)	(26,502)	(17,204)
Income Taxes		(65)	(10)	0
Profit (Loss) for the year	[2]	(40,935)	(26,512)	(17,204)
Cardiology [member]
Disclosure of operating segments [line items]
Revenue recognized at a point in time				5
Revenue				5
Cost of Sales
Gross Profit				5
Research & Development expenses		(587)	(142)	(124)
Net Other income/(expenses)		(63)	(108)	(2)
Operating Loss		(650)	(250)	(121)
Net financial income/(expenses)		(19)	107	(33)
Loss before taxes		(669)	(143)	(154)
Profit (Loss) for the year		(669)	(143)	(154)
Immuno-oncology [member]
Disclosure of operating segments [line items]
Revenue recognized over time				0
Revenue		0	0	0
Cost of Sales
Research & Development expenses		(18,341)	(20,631)	(21,398)
Change in fair value of contingent consideration		14,679	847	9,228
Impairment of Oncology intangible assets		(35,084)
Net Other income/(expenses)		9,148	3,507	4,582
Operating Loss		(29,598)	(16,277)	(7,589)
Net financial income/(expenses)		(132)	(165)	(182)
Loss before taxes		(29,730)	(16,442)	(7,771)
Income Taxes		(65)
Profit (Loss) for the year		(29,795)	(16,442)	(7,771)
Corporate [member]
Disclosure of operating segments [line items]
Cost of Sales
General & Administrative expenses		(10,546)	(9,908)	(9,315)
Net Other income/(expenses)		(63)	44	38
Operating Loss		(10,609)	(9,864)	(9,277)
Net financial income/(expenses)		138	(53)	(3)
Loss before taxes		(10,471)	(9,917)	(9,280)
Income Taxes		0	(10)
Profit (Loss) for the year		€ (10,471)	€ (9,927)	€ (9,280)
[1]The operating loss arises from the Company’s loss for the period before deduction of financial income, financial expenses and income taxes. The purpose of this measure by Management is to identify the Company’s results in connection with its operating activities.[2]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

Intangible Assets - Summary of

Intangible Assets - Summary of Intangible Assets (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Beginning balance	€ 36,168
Impairment		€ 0
Accumulated amortization	(35,084)	0	€ 0
Ending balance	864	36,168
Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	49,193	48,995
Additions	876	214
Divestiture	(617)	(16)
Ending balance	49,452	49,193	48,995
Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(13,025)	(12,527)
Amortisation charge	(613)	(217)
Divestiture	134	16
Accumulated amortization	(48,588)	(13,025)
Ending balance	(48,588)	(13,025)	(12,527)
Accumulated impairment [member]
Disclosure of detailed information about intangible assets [line items]
Impairment	(35,084)
Goodwill [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	883
Ending balance	0	883
Goodwill [member] | Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	883	883
Divestiture	(239)
Ending balance	644	883	883
Goodwill [member] | Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Accumulated amortization	(644)
Ending balance	(644)
Goodwill [member] | Accumulated impairment [member]
Disclosure of detailed information about intangible assets [line items]
Impairment	(644)
In-process research and development [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	33,678
Ending balance	0	33,678
In-process research and development [member] | Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	33,678	33,678
Ending balance	33,678	33,678	33,678
In-process research and development [member] | Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Accumulated amortization	(33,678)
Ending balance	(33,678)
In-process research and development [member] | Accumulated impairment [member]
Disclosure of detailed information about intangible assets [line items]
Impairment	(33,678)
Development cost [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	474
Ending balance	408	474
Development cost [member] | Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	1,084	1,084
Ending balance	1,084	1,084	1,084
Development cost [member] | Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(610)	(543)
Amortisation charge	(66)	(67)
Accumulated amortization	(676)	(610)
Ending balance	(676)	(610)	(543)
Patents, licences, trademarks [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	1,099
Ending balance	456	1,099
Patents, licences, trademarks [member] | Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	13,285	13,071
Additions	876	214
Divestiture	(213)
Ending balance	13,948	13,285	13,071
Patents, licences, trademarks [member] | Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(12,186)	(12,052)
Amortisation charge	(547)	(134)
Divestiture	3
Accumulated amortization	(13,492)	(12,186)
Ending balance	(13,492)	(12,186)	(12,052)
Patents, licences, trademarks [member] | Accumulated impairment [member]
Disclosure of detailed information about intangible assets [line items]
Impairment	(762)
Software [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	34
Ending balance	0	34
Software [member] | Capitalized costs [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	263	279
Additions		0
Divestiture	(165)	(16)
Ending balance	98	263	279
Software [member] | Accumulated depreciation and amortisation [member]
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(229)	(229)
Amortisation charge	0	(16)
Divestiture	131	16
Accumulated amortization	(98)	(229)
Ending balance	€ (98)	€ (229)	€ (229)

Intangible Assets - Additional

Intangible Assets - Additional Information (Detail) € in Thousands, $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2022	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 EUR (€)	Jan. 01, 2022 EUR (€)	Jan. 01, 2022 USD ($)
Disclosure of detailed information about intangible assets [line items]
Intellectual property protection period		20 years
Impairment loss			€ 0
Disposals, intangible assets other than goodwill		€ 300
Horizon discovery agreement [member]
Disclosure of detailed information about intangible assets [line items]
CAR-T Therapies acquired		900
Milestone Payments		€ 300
CorQuest LLC [member]
Disclosure of detailed information about intangible assets [line items]
Description of key assumptions		The recoverable amount associated to this CGU is calculated based on the fair value less costs to sell model using Level 3 fair value measurements for which the Group developed unobservable inputs and requires the use of assumptions. As of December 31, 2021, the calculations used cash flow projections based on business plan ending in 2040 based on probability of success of CYAD-02, CYAD-101 and CYAD-211 product candidates as well as extrapolations of projected cash flows resulting from the future expected sales on CYAD-101 and CYAD-211 and sublicense income associated with CYAD-02. CGU recoverable value, determined accordingly, exceeded its carrying amount.
Discount Rate WACC [Member]
Disclosure of detailed information about intangible assets [line items]
Percentage of estimated discount rate			13.40%
C-Cathez [Member]
Disclosure of detailed information about intangible assets [line items]
Intangible asset amortization period	2 years
Intangible assets				€ 900	$ 1
Bottom of range [member] | Software [member]
Disclosure of detailed information about intangible assets [line items]
Intangible asset amortization period		3 years
Top of range [member] | Software [member]
Disclosure of detailed information about intangible assets [line items]
Intangible asset amortization period		5 years

Intangible Assets - Summary o_2

Intangible Assets - Summary of Probabilities of Success for Products (Detail)	12 Months Ended
	Dec. 31, 2022
CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	7.50%
CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	4.60%
CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	7.50%
Phase I [member] | CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	100%
Phase I [member] | CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	100%
Phase I [member] | CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	100%
Phase I to II [member] | CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	50%
Phase I to II [member] | CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	49%
Phase I to II [member] | CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	50%
Phase II to III [member] | CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	28%
Phase II to III [member] | CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	23%
Phase II to III [member] | CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	28%
Phase III to BLA [member] | CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	60%
Phase III to BLA [member] | CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	43%
Phase III to BLA [member] | CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	60%
BLA to approval [member] | CYAD 02 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	90%
BLA to approval [member] | CYAD-101 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	93%
BLA to approval [member] | CYAD-211 [member]
Disclosure of detailed information about intangible assets [line items]
Probablity of success percentage	90%

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Changes in Carrying Value of Property, Plant and Equipment (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	€ 3,248
Ending balance	309	€ 3,248
Capitalized costs [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	11,092	10,846
Additions	277	422
Disposals	(8,299)	(192)
Currency translation adjustments	12	16
Transfers to Assets held for sale	(1,630)
Ending balance	1,452	11,092
Accumulated depreciation [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	(7,844)	(6,727)
Depreciation charge	(827)	(1,303)
Disposals	6,147	191
Currency translation adjustments	(5)	(5)
Transfers to Assets held for sale	1,385
Ending balance	(1,144)	(7,844)
Property [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	1,744
Ending balance	0	1,744
Property [Member] | Capitalized costs [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,025	3,001
Additions	146	24
Disposals	(3,171)	0
Currency translation adjustments	0	0
Transfers to Assets held for sale	0
Ending balance	0	3,025
Property [Member] | Accumulated depreciation [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	(1,281)	(827)
Depreciation charge	(439)	(454)
Disposals	1,720	0
Currency translation adjustments	0	0
Transfers to Assets held for sale	0
Ending balance	0	(1,281)
Equipment [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	812
Ending balance	309	812
Equipment [Member] | Capitalized costs [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	3,760	3,563
Additions	116	388
Disposals	(2,180)	(192)
Currency translation adjustments	1	1
Transfers to Assets held for sale	(421)
Ending balance	1,276	3,760
Equipment [Member] | Accumulated depreciation [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	(2,948)	(2,625)
Depreciation charge	(268)	(512)
Disposals	1,834	191
Currency translation adjustments	0	(2)
Transfers to Assets held for sale	414
Ending balance	(968)	(2,948)
Furniture [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	12
Ending balance	0	12
Furniture [member] | Capitalized costs [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	250	250
Additions	15	0
Disposals	(45)	0
Currency translation adjustments	0	0
Transfers to Assets held for sale	(220)
Ending balance	0	250
Furniture [member] | Accumulated depreciation [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	(238)	(214)
Depreciation charge	0	(24)
Disposals	18	0
Currency translation adjustments	0	0
Transfers to Assets held for sale	220
Ending balance	0	(238)
Leasehold improvements [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	680
Ending balance	0	680
Leasehold improvements [member] | Capitalized costs [member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	4,057	4,032
Additions	0	10
Disposals	(2,903)	0
Currency translation adjustments	11	15
Transfers to Assets held for sale	(989)
Ending balance	176	4,057
Leasehold improvements [member] | Accumulated depreciation [Member]
Disclosure of detailed information about property, plant and equipment [line items]
Beginning balance	(3,377)	(3,061)
Depreciation charge	(120)	(313)
Disposals	2,575	0
Currency translation adjustments	(5)	(3)
Transfers to Assets held for sale	751
Ending balance	€ (176)	€ (3,377)

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Statement [Line Items]
capitalized costs	€ 309		€ 3,248
Asset held for sale	800
Right of use assets write off	600
Capitalized assets write off	900
Belgium [member]
Statement [Line Items]
Asset held for sale		€ 6,000
Leasehold improvements [member]
Statement [Line Items]
capitalized costs	€ 0	€ 100	€ 680

Non-Current Trade Receivables_2

Non-Current Trade Receivables And Other Non-Current Assets - Summary of Detailed Information About Non-current Trade Receivables (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of other non current assets [line items]
Non-current trade receivables Mesoblast license agreement	€ 0	€ 2,209
Mesoblast license agreement [member]
Disclosure of other non current assets [line items]
Non-current trade receivables Mesoblast license agreement	€ 0	€ 2,209

Non-Current Trade Receivables_3

Non-Current Trade Receivables And Other Non-Current Assets - Summary of Non-current Financial Assets (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2017
Disclosure of Other Noncurrent Assets [abstract]
R&D Tax credit receivable	€ 3,454	€ 3,764	€ 1,200
Total Non-current Grant receivables	3,454	3,764
Deposits	264	262
Total Other non-current assets	€ 264	€ 262

Non-Current Trade Receivables_4

Non-Current Trade Receivables And Other Non-Current Assets - Additional Information (Detail) € in Thousands, $ in Millions			12 Months Ended
	Jan. 17, 2022 EUR (€)	Jan. 17, 2022 USD ($)	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 EUR (€)	Dec. 31, 2021 USD ($)	Dec. 31, 2017 EUR (€)
Disclosure Of Other Non Current Assets [line items]
R&D Tax credit receivable			€ 3,454	€ 3,764		€ 1,200
R&D Tax credit receivable increase (decrease)			500
Non-current trade receivables			0	2,209
Mesoblast license agreement [member]
Disclosure Of Other Non Current Assets [line items]
Non-current trade receivables			0	2,209
Non-current trade receivables Mesoblast license agreement, Settlement difference	€ 900	$ 1
Amendment Entered With Mesoblast To Convert The License Into Non Exclusive [Member] | Mesoblast license agreement [member]
Disclosure Of Other Non Current Assets [line items]
Non-current trade receivables				€ 2,200	$ 2.5
Non-current trade receivables decrease due to settlement	1,500
Consideration receivable	€ 1,500
2017 Tax Credit [Member]
Disclosure Of Other Non Current Assets [line items]
R&D Tax credit receivable			800
Mesoblast [member] | License And collaboration Agreements [member]
Disclosure Of Other Non Current Assets [line items]
Non-current trade receivables			€ 2,200

Trade, Other Receivables and _3

Trade, Other Receivables and Other assets - Summary of Trade Receivables and Other Assets (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of trade and other receivables [abstract]
Trade receivables	€ 909	€ 203
Advance deposits	209	246
Net Investment in Lease	0	219
Total Trade and Other receivables	1,118	668
Current Grant receivables (RCAs)	0	1,121
Current Grant receivables (Others)	0	274
Total Current Grant receivables	0	1,395
Prepaid expenses	667	1,688
VAT receivable	316	483
Income and other tax receivables	34	40
Total Other current assets	1,017	2,211
Total Trade receivables, advances and other current assets	€ 2,135	€ 4,274

Trade, Other Receivables and _4

Trade, Other Receivables and Other assets - Additional Information (Detail) € in Millions	12 Months Ended
	Dec. 31, 2022 EUR (€)
Disclosure of trade and other receivables [line items]
Increase in trade receivables	€ 0.3
Decrease in other current assets	1.2
Reversal of transaction costs	0.6
Net investment in finance lease	0
C-Cathez [Member]
Disclosure of trade and other receivables [line items]
Increase in trade receivables	€ 0.2

Cash and Cash Equivalents - Sum

Cash and Cash Equivalents - Summary of Cash and Cash Equivalents (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash and cash equivalents [abstract]
Cash at bank and on hand	€ 12,445	€ 30,018
Total	€ 12,445	€ 30,018	€ 17,234	€ 39,338

Cash and Cash Equivalents - Add

Cash and Cash Equivalents - Additional Information (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement [Line Items]
Cash and cash equivalents	€ 12,445	€ 30,018	€ 17,234	€ 39,338
Cash burned	€ 17,600

Investment in Subsidiaries - Su

Investment in Subsidiaries - Summary of Consolidated Subsidiaries (Detail)	12 Months Ended
	Dec. 31, 2022
Celyad SA [Member] | Belgium [member]
Disclosure of subsidiaries [line items]
Name	Celyad SA
Country of Incorporation and Place of Business	BE
Nature of Business	Biopharma
Celyad Inc [member] | USA [member]
Disclosure of subsidiaries [line items]
Name	Celyad Inc
Country of Incorporation and Place of Business	US
Nature of Business	Biopharma
Proportion of Propo ordinary ordina shares directly held by held by parent (%)	100%
Proportion of ordinary shares held by the group (%)	100%
Proportion of ordinary shares held by non-controlling interests (%)	0%
Corquest Medical Inc [member] | USA [member]
Disclosure of subsidiaries [line items]
Name	CorQuest Medical Inc
Country of Incorporation and Place of Business	US
Nature of Business	Medical Device
Proportion of Propo ordinary ordina shares directly held by held by parent (%)	100%
Proportion of ordinary shares held by the group (%)	100%
Proportion of ordinary shares held by non-controlling interests (%)	0%
Biological Manufacturing Services SA [member] | Belgium [member]
Disclosure of subsidiaries [line items]
Name	Biological Manufacturing Services SA
Country of Incorporation and Place of Business	BE
Nature of Business	Manufacturing
Proportion of Propo ordinary ordina shares directly held by held by parent (%)	100%
Proportion of ordinary shares held by the group (%)	100%
Proportion of ordinary shares held by non-controlling interests (%)	0%

Share Capital Issued - Summary

Share Capital Issued - Summary of Share Capital Issued (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of classes of share capital [abstract]
Total number of issued and outstanding shares	22,593,956	22,593,956
Total share capital	€ 78,585	€ 78,585

Share Capital Issued - Addition

Share Capital Issued - Additional Information (Detail) € / shares in Units, $ in Millions

1 Months Ended

12 Months Ended

Dec. 08, 2021 EUR (€) shares

Oct. 11, 2021

Jun. 14, 2021 EUR (€) shares

May 25, 2021 EUR (€)

May 21, 2021 EUR (€) shares

Jan. 08, 2021 USD ($)

Dec. 11, 2020

Oct. 25, 2019

Oct. 26, 2018

May 18, 2018 EUR (€)

May 18, 2018 USD ($)

Jun. 29, 2017

Dec. 08, 2016

Nov. 05, 2015

May 05, 2014

Jul. 15, 2013 EUR (€) shares

Jun. 11, 2013 EUR (€)

May 31, 2013 EUR (€)

May 06, 2013

May 05, 2011 EUR (€)

Oct. 29, 2010 EUR (€) € / shares shares

Oct. 14, 2010 EUR (€) € / shares shares

Dec. 23, 2008 EUR (€) shares

Aug. 31, 2007 EUR (€) shares

Sep. 30, 2019 EUR (€)

Sep. 30, 2019 USD ($)

Aug. 31, 2017 EUR (€) € / shares shares

Jun. 30, 2015 EUR (€) shares

Mar. 31, 2015 EUR (€) shares

Jan. 31, 2015 EUR (€) shares

Jun. 30, 2014 EUR (€) shares

Dec. 31, 2022 EUR (€) € / shares shares

Dec. 31, 2021 EUR (€) shares

Dec. 31, 2021 EUR (€) shares

Dec. 31, 2017 EUR (€) shares

Dec. 31, 2015 EUR (€) shares

Dec. 31, 2014 EUR (€) shares

May 31, 2019 EUR (€)

Jul. 05, 2013 EUR (€) € / shares shares

Jul. 24, 2007 EUR (€) shares

Disclosure of classes of share capital [line items]

Issued capital

€ 78,585,000

€ 78,585,000

€ 78,585,000

Number of ordinary shares | shares

22,593,956

22,593,956

22,593,956

Common stock , par value | € / shares

€ 3.48

Date of incorporation

Jul. 24, 2007

Share capital

€ 62,500

Shares issued | shares

188,800

188,800

Proceeds from capital increase

€ 12,100,809

Warrants exercised | shares

225,966

6,749

139,415

Increase in capital

€ 18,925,474

€ 25,000,000

€ 625,000

Convertible loans converted to shares, amount

€ 28,645,000

Increase in capital and issue premium by contribution in cash

7,000

Proceeds from issuing shares

€ 900,000

€ 900,000

€ (124,000)

€ 36,568,000

Cost related to capital increase

€ 2,800,000

Description of authorization invested in board of directors

On June 11, 2013, the Extraordinary General Shareholders’ Meeting of Celyad SA authorized the Board of Directors to increase the share capital of the Company, in one or several times, and under certain conditions set forth in extenso in the articles of association. This authorization is valid for a period of five years starting on July 26, 2013 and until July 26, 2018. The Board of Directors may increase the share capital of the Company within the framework of the authorized capital for an amount

Expected increase in capital

€ 21,413,000

Shares issued related to exercise of warrants | shares

225,966

6,749

139,415

Warrants exercise periods

7 years

7 years

5 years

5 years

5 years

5 years

10 years

10 years

10 years

Over four different exercise periods

Over three different exercise periods

Over four different exercise periods

Decrease In Share Premium

€ 172,300,000

Common Stock, Capital Shares Reserved for Future Issuance | shares

1,361,242

ShareBasedCompensationPlan [Member]

Disclosure of classes of share capital [line items]

Common Stock, Capital Shares Reserved for Future Issuance | shares

323.7

Lincoln Park Capital Fund LLC [Member]

Disclosure of classes of share capital [line items]

Shares issued | shares

1,962,812

1,962,812

Proceeds from issuing shares

€ 9,200,000

Equity purchase agreement consideration paid | $

$ 40

Equity purchase agreement term

24 months

Purchase of american depositary shares value | $

$ 40

Equity purchase agreement, Remaining access to the agreement

€ 28,000,000

Oncyte LLC [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

93,087

Increase in capital

€ 3,452,000

Initial public offering [member]

Disclosure of classes of share capital [line items]

Issued capital

€ 23,002,000

Common stock , par value | € / shares

€ 16.65

Shares issued | shares

1,460,000

1,381,500

Increase in capital

€ 87,965,000

Proceeds from issuing shares

€ 26,452,000

Over allotment option [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

207,225

Proceeds from issuing shares

€ 3,450,000

Share capital [member]

Disclosure of classes of share capital [line items]

Increase in capital

€ 23,000

€ 488,000

Convertible loans converted to shares, amount

5,026,000

Share premium [member]

Disclosure of classes of share capital [line items]

Increase in capital

€ 196,000

€ 500,000

Convertible loans converted to shares, amount

6,988,000

Increase decrease in capital, Cumulative amount

€ 43,300,000

Cumulative gain loss absorption that has been approved and recorded

€ 234,600,000

Decrease In Share Premium Due to Absorption of Accounting Losses

€ 43,300,000

Private placement [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

713,380

Increase in capital

€ 31,745,000

Other reserves [member]

Disclosure of classes of share capital [line items]

Convertible loans converted to shares, amount

€ 16,631,000

Capital redemption reserve [member]

Disclosure of classes of share capital [line items]

Percentage of annual net profits allocated to a legal reserve based on certain conditions

5%

Threshold percentage of legal reserve to share capital

10%

Conversion of Loan D [member]

Disclosure of classes of share capital [line items]

Nominal amount

€ 2,010,000

Round B Investors [member]

Disclosure of classes of share capital [line items]

Shares authorized | shares

875,759

Round B Investors [member] | Convertible loan [member]

Disclosure of classes of share capital [line items]

Capital contribution

€ 2,387,049

Round B Investors [member] | Cash 1 [member]

Disclosure of classes of share capital [line items]

Capital contribution

4,849,624

Round B Investors [member] | Uncalled Cash [member]

Disclosure of classes of share capital [line items]

Capital contribution

€ 1,949,624

Celdara Medical [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 32.35

Shares issued | shares

328,275

Proceeds from issuing shares

€ 43,000,000

€ 16,400,000

Description of share price calculation

average market price

Issue Of Equity

€ 46,100,000

$ 54.4

€ 18,200,000

$ 20

Celdara Medical [member] | Share capital [member]

Disclosure of classes of share capital [line items]

Increase in capital

€ 1,141,000

Celdara Medical [member] | Share premium [member]

Disclosure of classes of share capital [line items]

Increase in capital

€ 9,479,000

CFIP CLYD LLC [Member] | Private placement [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

6,500,000

Proceeds from issuing shares

€ 28,900,000

Mayo Clinic [member]

Disclosure of classes of share capital [line items]

Contribution in kind of the upfront fee that was due upon execution of the Mayo Licence

€ 9,500,000

Medisun International Limited [member]

Disclosure of classes of share capital [line items]

Shares subscribed | shares

568,180

Class A shares [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

409,375

Class A shares [member] | Round B Investors [member]

Disclosure of classes of share capital [line items]

Shares authorized | shares

671,107

Class A shares [member] | Mayo Clinic [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

261,732

Class B shares [member] | Conversion of Loan D [member]

Disclosure of classes of share capital [line items]

Capital contribution

€ 2,018,879.2

Share conversion price per share | € / shares

€ 35.36

Class B shares [member] | Conversion of Loan C [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

92.068

Capital contribution

€ 3,255,524.48

Share conversion price per share | € / shares

€ 35.36

Class B shares [member] | Round B Investors [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

204,652

Shares authorized | shares

204,652

Class B shares [member] | Existing investor [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 35.36

Shares issued | shares

73.793

Capital contribution

€ 2,609,320.48

Class B shares [member] | New Investor [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 44.2

Shares issued | shares

9.048

Capital contribution

€ 399,921.6

Class B shares [member] | Round C Investors [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

12.3

Class B shares [member] | Mayo Clinic [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 44.2

Shares issued | shares

69.455

Contribution in kind

€ 3,069,911

Class B shares [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 35.36

Shares issued | shares

67,502

Class B shares [member] | Conversion of Loan D [member]

Disclosure of classes of share capital [line items]

Shares issued | shares

57,095

Class B shares [member] | Existing investor [member]

Disclosure of classes of share capital [line items]

Common stock , par value | € / shares

€ 2,244

Shares issued | shares

21,000

Capital contribution

€ 471.24

Warrant A [member] | Round C Investors [member]

Disclosure of classes of share capital [line items]

Warrants exercised | shares

12.3

Proceeds from exercise of warrants

€ 276.012

Warrants exercise price | € / shares

€ 2,244

Share Capital Issued - Summar_2

Share Capital Issued - Summary of Share Issuances Occurred Since the Incorporation of the Company (Detail) - EUR (€) € / shares in Units, € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jun. 14, 2021	May 21, 2021
Disclosure of classes of share capital [line items]
# of shares					188,800	188,800
Par value		€ 3.48
Beginning balance		€ 43,639	€ 30,994	€ 45,619
Transaction costs associated with capital increases			(2,583)
Loss for the period	[1]	(40,935)	(26,512)	(17,204)
Share Based Payment		1,624	2,172	2,782
Currency translation differences		4	42	(5)
Remeasurements of defined benefit obligation		(15)	554	(197)
Ending balance		4,317	43,639	30,994
Share capital [member]
Disclosure of classes of share capital [line items]
Beginning balance		78,585	48,513	48,513
Capital increase			30,072
Ending balance		78,585	78,585	48,513
Share premium [member]
Disclosure of classes of share capital [line items]
Beginning balance		6,317	43,349	43,349
Reduction of share premium by absorption of losses			(43,349)
Capital increase			8,900
Transaction costs associated with capital increases			(2,583)
Ending balance		6,317	6,317	43,349
Capital reduction reserve [member]
Disclosure of classes of share capital [line items]
Beginning balance	[2]	234,562	191,213	191,213
Reduction of share premium by absorption of losses	[2]		43,349
Ending balance	[2]	234,562	234,562	191,213
Other reserves [member]
Disclosure of classes of share capital [line items]
Beginning balance	[2]	33,172	30,958	28,181
Share Based Payment	[2]	1,624	2,172	2,782
Currency translation differences	[2]	4	42	(5)
Ending balance	[2]	34,800	33,172	30,958
Accumulated deficit [Member]
Disclosure of classes of share capital [line items]
Beginning balance	[2]	(308,997)	(283,039)	(265,637)
Loss for the period	[2]	(40,935)	(26,512)	(17,204)
Remeasurements of defined benefit obligation	[2]	(15)	554	(197)
Ending balance	[2]	(349,947)	(308,997)	(283,039)
Number of shares [member]
Disclosure of classes of share capital [line items]
Beginning balance		22,593,956	13,942,344
Capital increase			8,651,612
Ending balance		€ 22,593,956	€ 22,593,956	€ 13,942,344
Class A shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jul. 24, 2007
Description		Company incorporation
# of shares		409,375
Par value		€ 0.15
Class A shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 31, 2007
Description		Contribution in kind (upfront fee Mayo License)
# of shares		261,732
Par value		€ 36.3
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Dec. 23, 2008
Description		Capital increase (Round B)
# of shares		137,150
Par value		€ 35.36
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Dec. 23, 2008
Description		Contribution in kind (Loan B)
# of shares		67,502
Par value		€ 35.36
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in cash
# of shares		21,000
Par value		€ 22.44
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in kind (Loan C)
# of shares		92,068
Par value		€ 35.36
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in kind (Loan D)
# of shares		57,095
Par value		€ 35.36
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in cash
# of shares		73,793
Par value		€ 35.36
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Exercise of warrants
# of shares		12,300
Par value		€ 22.44
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in kind (Mayo receivable)
# of shares		69,455
Par value		€ 4,420
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 28, 2010
Description		Contribution in cash
# of shares		9,048
Par value		€ 4,420
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 31, 2013
Description		Contribution in kind (Loan E)
# of shares		118,365
Par value		€ 3,839
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 31, 2013
Description		Contribution in kind (Loan F)
# of shares		56,936
Par value		€ 3,839
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 31, 2013
Description		Contribution in kind (Loan G)
# of shares		654,301
Par value		€ 452
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 31, 2013
Description		Contribution in kind (Loan H)
# of shares		75,755
Par value		€ 3,071
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 31, 2013
Description		Contribution in cash
# of shares		219,016
Par value		€ 3,196
Class B shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 04, 2013
Description		Conversion of warrants
# of shares		2,409,176
Par value		€ 1
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 11, 2013
Description		Conversion of Class A and Class B shares in ordinary shares
# of shares		4,744,067
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jul. 05, 2013
Description		Initial Public Offering
# of shares		1,381,500
Par value		€ 1,665
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jul. 15, 2013
Description		Exercise of over-allotment option
# of shares		207,225
Par value		€ 1,665
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jan. 31, 2014
Description		Exercise of warrants issued in September 2008
# of shares		5,966
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jan. 31, 2014
Description		Exercise of warrants issued in May 2010
# of shares		333
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jan. 31, 2014
Description		Exercise of warrants issued in January 2013
# of shares		120,000
Par value		€ 452
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Apr. 30, 2014
Description		Exercise of warrants issued in September 2008
# of shares		2,366
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 16, 2014
Description		Capital increase
# of shares		284,090
Par value		€ 4,400
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 30, 2014
Description		Capital increase
# of shares		284,090
Par value		€ 4,400
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 04, 2014
Description		Exercise of warrants issued in September 2008
# of shares		5,000
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 04, 2014
Description		Exercise of warrants issued in October 2010
# of shares		750
Par value		€ 3,536
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Nov. 03, 2014
Description		Exercise of warrants issued in September 2008
# of shares		5,000
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jan. 21, 2015
Description		Contribution in kind (Celdara Medical LLC)
# of shares		93,087
Par value		€ 3,708
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Feb. 07, 2015
Description		Exercise of warrant issued in May 2010
# of shares		333
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Mar. 03, 2015
Description		Capital increase
# of shares		713,380
Par value		€ 4,450
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		May 11, 2015
Description		Exercise of warrant issued in May 2010
# of shares		500
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 24, 2015
Description		Capital increase
# of shares		1,460,000
Par value		€ 6,025
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 04, 2015
Description		Exercise of warrant issued in May 2010
# of shares		666
Par value		€ 2,244
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 04, 2015
Description		Exercise of warrant issued in October 2010
# of shares		5,250
Par value		€ 3,536
Ordinary shares twenty [member]
Disclosure of classes of share capital [line items]
Transaction date		Feb. 01, 2017
Description		Exercise of warrant issued in May 2013
# of shares		207,250
Par value		€ 264
Ordinary shares twenty one [member]
Disclosure of classes of share capital [line items]
Transaction date		May 02, 2017
Description		Exercise of warrant issued in May 2013
# of shares		4,900
Par value		€ 264
Ordinary shares twenty two [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 01, 2017
Description		Exercise of warrant issued in May 2013
# of shares		7,950
Par value		€ 264
Ordinary shares twenty three [member]
Disclosure of classes of share capital [line items]
Transaction date		Aug. 23, 2017
Description		Contribution in kind (Celdara Medical LLC)
# of shares		328,275
Par value		€ 3,235
Ordinary shares twenty four [member]
Disclosure of classes of share capital [line items]
Transaction date		Nov. 09, 2017
Description		Exercise of warrant issued in May 2013
# of shares		5,000
Par value		€ 264
Ordinary shares twenty five [member]
Disclosure of classes of share capital [line items]
Transaction date		Nov. 09, 2017
Description		Exercise of warrant issued in October 2010
# of shares		866
Par value		€ 3,536
Ordinary shares twenty six [member]
Disclosure of classes of share capital [line items]
Transaction date		Feb. 07, 2018
Description		Exercise of warrant issued in May 2013
# of shares		4,500
Par value		€ 264
Ordinary shares twenty seven [member]
Disclosure of classes of share capital [line items]
Transaction date		May 22, 2018
Description		Capital increase
# of shares		2,070,000
Par value		€ 22.29
Ordinary shares twenty eight [member]
Disclosure of classes of share capital [line items]
Transaction date		Sep. 16, 2019
Description		Capital increase
# of shares		2,000,000
Par value		€ 9.08
Ordinary shares twenty nine [member]
Disclosure of classes of share capital [line items]
Transaction date		Jan. 08, 2021
Description		Capital increase
# of shares		262,812
Par value		€ 4.94
Ordinary shares thirty [member]
Disclosure of classes of share capital [line items]
Transaction date		Mar. 29, 2021
Description		Capital increase
# of shares		200,000
Par value		€ 6.19
Ordinary shares thirty one [member]
Disclosure of classes of share capital [line items]
Transaction date		Apr. 09, 2021
Description		Capital increase
# of shares		300,000
Par value		€ 5.83
Ordinary shares thirty two [member]
Disclosure of classes of share capital [line items]
Transaction date		Apr. 29, 2021
Description		Capital increase
# of shares		300,000
Par value		€ 5.23
Ordinary shares thirty three [member]
Disclosure of classes of share capital [line items]
Transaction date		May 21, 2021
Description		Capital increase
# of shares		182,000
Par value		€ 4.58
Ordinary shares thirty four [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 14, 2021
Description		Capital increase
# of shares		6,800
Par value		€ 4.98
Ordinary shares thirty five [member]
Disclosure of classes of share capital [line items]
Transaction date		Jun. 28, 2021
Description		Capital increase
# of shares		300,000
Par value		€ 4.46
Ordinary shares thirty six [member]
Disclosure of classes of share capital [line items]
Transaction date		Jul. 22, 2021
Description		Capital increase
# of shares		300,000
Par value		€ 3.46
Ordinary shares thirty seven [member]
Disclosure of classes of share capital [line items]
Transaction date		Oct. 20, 2021
Description		Capital increase
# of shares		300,000
Par value		€ 3.38
Ordinary shares thirty eight [member]
Disclosure of classes of share capital [line items]
Transaction date		Dec. 08, 2021
Description		Capital increase
# of shares		6,500,000
Par value		€ 4.44
[1]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.[2]Pursuant to Belgian law (“CCA”), the calculation of amounts available for distribution to shareholders, as dividends or otherwise, must be determined on the basis of the Company’s standalone non-consolidated statutory financial statements of Celyad Oncology SA prepared under Belgian GAAP, and not on the basis of IFRS consolidated financial statements. For more information, see Note 15.

Share-based Payments - Changes

Share-based Payments - Changes in Number of Warrants Outstanding (Detail)											12 Months Ended
	Oct. 05, 2022 shares	Oct. 11, 2021 shares Warrant	Dec. 11, 2020 shares	Oct. 25, 2019 Warrant	Oct. 26, 2018 Warrant	Jun. 29, 2017 Warrant	Dec. 08, 2016 Warrant	Nov. 05, 2015 Warrant	May 05, 2014 Warrant	May 06, 2013 Warrant € / shares	Dec. 31, 2022 Warrant € / shares	Dec. 31, 2021 Warrant € / shares
Disclosure of terms and conditions of share-based payment arrangement [abstract]
Weighted average exercise price, outstanding, beginning of period											€ 13.06	€ 17
Weighted average exercise price, granted											1.82	5.29
Weighted average exercise price, forfeited											2.74	4.94
Weighted average exercise price, expired											15.8	10.23
Weighted average exercise price outstanding, end of period										€ 2.64	€ 8.36	€ 13.06
Number of warrants outstanding, beginning of period | Warrant											2,136,556	1,488,006
Number of warrants, granted	0	874.2	557,050	602,025	426,050	334,400	45,000	353,550	94,400	253,150	594,450	760,800
Number of warrants, forfeited | Warrant											(109,108)	(77,250)
Number of warrants, exercised			(561,525)						(100,000)	(253,150)	0	0
Number of warrants, expired | Warrant											(282,252)	(35,000)
Number of warrants outstanding, end of period	0	819,983	498,883	529,950	365,817	0	7,500	79,315	35,698	2,500	2,339,646	2,136,556

Share-based Payments - Addition

Share-based Payments - Additional Information (Detail) € / shares in Units, € in Millions											12 Months Ended
	Oct. 05, 2022 shares	Oct. 11, 2021 shares Warrant € / shares	Dec. 11, 2020 shares € / shares	Oct. 25, 2019 Warrant € / shares shares	Oct. 26, 2018 Warrant € / shares shares	Jun. 29, 2017 Warrant € / shares shares	Dec. 08, 2016 Warrant € / shares	Nov. 05, 2015 Warrant € / shares shares	May 05, 2014 Warrant € / shares shares	May 06, 2013 Warrant € / shares shares	Dec. 31, 2022 EUR (€) Warrant € / shares shares	Dec. 31, 2021 EUR (€) Warrant € / shares	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2014	Oct. 11, 2021 Warrant $ / shares	Dec. 31, 2020 Warrant € / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrant exercised			561,525						100,000	253,150	0	0
Number of warrants authorized | shares	323.7	777,050		939,500	700,000	520,000		466,000	100,000	266,241	568,500
Number of warrants offered	0	874.2	557,050	602,025	426,050	334,400	45,000	353,550	94,400	253,150	594,450	760,800
Number of warrants outstanding	0	819,983	498,883	529,950	365,817	0	7,500	79,315	35,698	2,500	2,339,646	2,136,556				819,983	1,488,006
Warrants expiration date		3 years	3 years	3 years	3 years	3 years	3 years	3 years	3 years	3 years
Percentage of warrants vested		100%	100%	100%	100%	100%	100%	100%	100%	100%
Exercise price of the different tranches ranges										€ 2.64	€ 8.36	€ 13.06					€ 17
Warrants exercise period		7 years	7 years	5 years	5 years	5 years	5 years	10 years	10 years	10 years			Over four different exercise periods	Over three different exercise periods	Over four different exercise periods
Net expense recognized | €											€ 1.6	€ 2.2
Warrants Issued And Outstanding Percentage											9.38%
Percentage of total number of all issued and outstanding shares											8.57%
Warrants, Void terms		void after the 31st of December of the 7th year	void after the 31st of December of the 7th year	oid after the 31st of December of the 5th year	void after the 31st of December of the 5th year
WarrantsYearOfExpiry											2022 years
Bottom of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise price of the different tranches ranges | (per share)			€ 3.72	€ 5.97	€ 9.36	€ 31.34	€ 17.6	€ 15.9	€ 33.49							$ 1.64
Top of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise price of the different tranches ranges		€ 3.75	€ 6.81	€ 9.84	€ 22.04	€ 48.89	€ 36.81	€ 34.65	€ 45.05
Warrants plan issuance date 5 November 2015 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
New issue of warrants | Warrant							100,000

Share-based Payments - Summary

Share-based Payments - Summary of Warrants Outstanding (Detail)

12 Months Ended

Dec. 31, 2022 Warrant $ / shares

Oct. 05, 2022 shares

Dec. 31, 2021 Warrant

Oct. 11, 2021 Warrant

Dec. 31, 2020 Warrant

Dec. 11, 2020 shares

Oct. 25, 2019 Warrant

Oct. 26, 2018 Warrant

Jun. 29, 2017 Warrant

Dec. 08, 2016 Warrant

Nov. 05, 2015 Warrant

May 05, 2014 Warrant

May 06, 2013 Warrant

Disclosure of terms and conditions of share-based payment arrangement [line items]

Number of warrants outstanding as of 31 December

2,339,646

0

2,136,556

819,983

1,488,006

498,883

529,950

365,817

0

7,500

79,315

35,698

2,500

06 May 2013 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

06 May 2013

Vesting date

06 May 2016

Expiry date

06 May 2023

Number of warrants outstanding as of 31 December | Warrant

2,500

2,500

Exercise price per share | $ / shares

$ 2.64

05 May 2014 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

05 May 2014

Vesting date

05 May 2017

Expiry date

05 May 2024

Number of warrants outstanding as of 31 December | Warrant

35,698

35,698

Exercise price per share | $ / shares

$ 38.25

05 November 2015 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

05 November 2015

Vesting date

05 November 2018

Expiry date

05 November 2025

Number of warrants outstanding as of 31 December | Warrant

79,315

79,315

Exercise price per share | $ / shares

$ 30.67

08 December 2016 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

08 December 2016

Vesting date

08 December 2019

Expiry date

08 December 2021

Number of warrants outstanding as of 31 December | Warrant

7,500

7,500

Exercise price per share | $ / shares

$ 32.04

29 June 2017 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

29 June 2017

Vesting date

29 June 2020

Expiry date

31 July 2022

Number of warrants outstanding as of 31 December | Warrant

0

282,251

Exercise price per share | $ / shares

$ 31.34

26 October 2018 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

26 October 2018

Vesting date

26 October 2021

Expiry date

31 December 2023

Number of warrants outstanding as of 31 December | Warrant

365,817

365,817

Exercise price per share | $ / shares

$ 18.26

25 October 2019 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

25 October 2019

Vesting date

25 October 2022

Expiry date

31 December 2024

Number of warrants outstanding as of 31 December | Warrant

529,950

549,842

Exercise price per share | $ / shares

$ 7.13

11 December 2020 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

11 December 2020

Vesting date

10 December 2023

Expiry date

31 December 2027

Number of warrants outstanding as of 31 December | Warrant

498,883

532,133

Exercise price per share | $ / shares

$ 6.24

11 October 2021 [member]

Disclosure of terms and conditions of share-based payment arrangement [line items]

Warrant plan issuance date

11 October 2021

Vesting date

11 October 2024

Expiry date

31 December 2028

Number of warrants outstanding as of 31 December | Warrant

819,983

281,500

Exercise price per share | $ / shares

$ 2.38

Share-based Payments - Summar_2

Share-based Payments - Summary of Fair Value of Warrants Determined At Grant Date (Detail)											12 Months Ended
	Oct. 05, 2022 shares	Oct. 11, 2021 shares Warrant	Dec. 11, 2020 shares	Oct. 25, 2019 Warrant	Oct. 26, 2018 Warrant	Jun. 29, 2017 Warrant	Dec. 08, 2016 Warrant	Nov. 05, 2015 Warrant	May 05, 2014 Warrant	May 06, 2013 Warrant	Dec. 31, 2022 EUR (€) Warrant € / shares	Dec. 31, 2021 Warrant	Dec. 31, 2020 Warrant
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants accepted	0	874.2	557,050	602,025	426,050	334,400	45,000	353,550	94,400	253,150	594,450	760,800
Number of warrants not fully vested as of 31 December 2022	0	819,983	498,883	529,950	365,817	0	7,500	79,315	35,698	2,500	2,339,646	2,136,556	1,488,006
Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											4,430,316
Number of warrants accepted											3,539,825
Number of warrants not fully vested as of 31 December 2022											1,608,700
06 May 2013 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											2,500	2,500
06 May 2013 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											266,241
Number of warrants accepted											253,150
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 2.64
Expected share value volatility											39.55%
Risk-free interest rate											2.06%
Average fair value | €											€ 12.44
Weighted average remaining contractual life											4 months 2 days
05 May 2014 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											35,698	35,698
05 May 2014 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											100,000
Number of warrants accepted											94,400
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 38.25
Expected share value volatility											67.73%
Risk-free interest rate											1.09%
Average fair value | €											€ 25.19
Weighted average remaining contractual life											1 year 4 months 2 days
05 November 2015 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											79,315	79,315
05 November 2015 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											466,000
Number of warrants accepted											353,550
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 30.67
Expected share value volatility											60.53%
Risk-free interest rate											0.26%
Average fair value | €											€ 20.04
Weighted average remaining contractual life											2 years 10 months 2 days
08 December 2016 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											7,500	7,500
08 December 2016 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											100,000
Number of warrants accepted											45,000
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 32.04
Expected share value volatility											61.03%
Risk-free interest rate											(0.40%)
Average fair value | €											€ 16.18
Weighted average remaining contractual life											1 year 25 days
29 June 2017 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											0	282,251
29 June 2017 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											520,000
Number of warrants accepted											334,400
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 31.34
Expected share value volatility											60.61%
Risk-free interest rate											(0.23%)
Average fair value | €											€ 15.58
Weighted average remaining contractual life											6 months 3 days
26 October 2018 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											365,817	365,817
26 October 2018 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											700,000
Number of warrants accepted											426,050
Number of warrants not fully vested as of 31 December 2022											0
Average exercise price | € / shares											€ 18.26
Expected share value volatility											58.82%
Risk-free interest rate											(0.06%)
Average fair value | €											€ 8.9
Weighted average remaining contractual life											9 months 25 days
25 October 2019 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											529,950	549,842
25 October 2019 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											939,500
Number of warrants accepted											602,025
Number of warrants not fully vested as of 31 December 2022											289,834
Average exercise price | € / shares											€ 7.13
Expected share value volatility											59.14%
Risk-free interest rate											(0.38%)
Average fair value | €											€ 3.99
Weighted average remaining contractual life											1 year 9 months 21 days
10 December 2020 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											561,525
Number of warrants accepted											557,050
Number of warrants not fully vested as of 31 December 2022											498,883
Average exercise price | € / shares											€ 6.24
Expected share value volatility											58.84%
Risk-free interest rate											(0.66%)
Average fair value | €											€ 3.45
Weighted average remaining contractual life											4 years 11 months 8 days
11 October 2021 [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants not fully vested as of 31 December 2022											819,983	281,500
11 October 2021 [member] | Black-Scholes Pricing Model [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of warrants issued											777,050
Number of warrants accepted											874,200
Number of warrants not fully vested as of 31 December 2022											819,983
Average exercise price | € / shares											€ 2.38
Expected share value volatility											56.86%
Risk-free interest rate											(0.30%)
Average fair value | €											€ 1.36
Weighted average remaining contractual life											5 years 9 months 10 days

Post Employment Benefits - Summ

Post Employment Benefits - Summary of Pension Obligations (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of defined benefit plans [abstract]
Pension obligations	€ 13	€ 53
Total	€ 13	€ 53

Post Employment Benefits - Addi

Post Employment Benefits - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 EUR (€) yr	Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [line items]
Employee contributions | €	€ 0
Mortality rate for men | yr	5
Mortality rate for women | yr	5
Actuarial assumption of retirement age	65 years
Yearly inflation rate	2.20%	2%
Actuarial assumption of yearly salary raise above inflation	1.50%	1.50%
Actuarial assumption of yearly discount rates	3.80%	1%
Percentage of reasonably possible increase decrease in actuarial assumption description	If the discount rate would decrease by 0.5% then, the defined benefit obligation would increase by 0.00%. If the discount rate would increase by 0.5% then the defined benefit obligation would decrease by 0.00%.
Expected contributions to pension benefit plans | €	€ 200,000
Percentage of plan assets invested in insurance product	100%
Age less than 55 [member]
Disclosure of net defined benefit liability (asset) [line items]
Actuarial assumption of withdrawal rate each year	13.50%
Age more than or equal to 55 [member]
Disclosure of net defined benefit liability (asset) [line items]
Actuarial assumption of withdrawal rate each year	0%

Post Employment Benefits - Su_2

Post Employment Benefits - Summary of Defined Benefit Amounts Recognized in the Statement of Financial Position (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [abstract]
Present value of funded obligations	€ 2,568	€ 2,408
Fair value of plan assets	(2,555)	(2,355)
Deficit of funded plans	13	53
Total deficit of defined benefit pension plans	13	53
Liability in the statement of financial position	€ 13	€ 53

Post Employment Benefits - Su_3

Post Employment Benefits - Summary of Change in Defined Benefit Liability (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	€ 53	€ 614
Current service cost	169	206	€ 233
Interest expense/(income)	3	(31)
Increase (decrease) in net defined benefit liability (asset)	225	789
Remeasurements
- Actuarial (Gain)/loss due to change in actuarial assumptions	(13)	(17)	187
- Actuarial (Gain)/loss due to change in demographic assumptions	0	36	0
- Actuarial (Gain)/Loss due to experience	26	(537)	24
Curtailment in year	(3)	0	0
Remeasurement of post-employment benefit obligation	10	(518)
Employer contributions:	(222)	(218)
Ending balance	13	53	614
Present value of obligation [member]
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	2,408	2,747
Current service cost	169	206
Interest expense/(income)	26	18
Increase (decrease) in net defined benefit liability (asset)	2,603	2,971
Remeasurements
- Actuarial (Gain)/loss due to change in actuarial assumptions	(13)	(17)
- Actuarial (Gain)/loss due to change in demographic assumptions		36
- Actuarial (Gain)/Loss due to experience	26	(537)
Curtailment in year	(3)
Remeasurement of post-employment benefit obligation	10	(518)
Employer contributions:		0
Benefits Paid	(45)	(45)
Ending balance	2,568	2,408	2,747
Fair value of plan assets [member]
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	2,355	2,133
Interest expense/(income)	23	49
Increase (decrease) in net defined benefit liability (asset)	2,378	2,182
Remeasurements
- Actuarial (Gain)/loss due to change in actuarial assumptions		0
- Actuarial (Gain)/loss due to change in demographic assumptions		0
- Actuarial (Gain)/Loss due to experience		0
Remeasurement of post-employment benefit obligation		0
Employer contributions:	222	218
Benefits Paid	(45)	(45)
Ending balance	€ 2,555	€ 2,355	€ 2,133

Post Employment Benefits - Su_4

Post Employment Benefits - Summary of Income Statement Charge Included in Operating Profit for Post- employment Benefits (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [abstract]
Current service cost	€ 169	€ 206	€ 233
Interest expense on DBO	26	18	30
Expected return on plan assets	(24)	(13)	(24)
Amount recognized on curtailment/settlement	(3)	0	0
Net periodic pension cost	€ 168	€ 211	€ 239

Post Employment Benefits - Su_5

Post Employment Benefits - Summary of Re-measurements Included in Other Comprehensive Loss (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [abstract]
Effect of changes in actuarial assumptions	€ (13)	€ (17)	€ 187
Effect of experience adjustments	26	(537)	24
Effect of changes in demographic assumptions	0	36	0
(Gain)/Loss on assets for the year	2	(36)	(14)
Remeasurement of post-employment benefit obligations	€ 15	€ (554)	€ 197

Other Reserves - Summary of Inf

Other Reserves - Summary of Information on Other Reserves (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of information on other reserves [Line Items]
Other reserves beginning balance	€ 33,172	€ 30,958
Vested share-based payments	1,624	2,172
Currency Translation differences subsidiaries	4	42
Other reserves ending balance	34,800	33,172
Share based payment reserve [member]
Disclosure of information on other reserves [Line Items]
Other reserves beginning balance	17,975	15,803
Vested share-based payments	1,624	2,172
Other reserves ending balance	19,599	17,975
Convertible loan [member]
Disclosure of information on other reserves [Line Items]
Other reserves beginning balance	16,631	16,631
Other reserves ending balance	16,631	16,631
Translation [member]
Disclosure of information on other reserves [Line Items]
Other reserves beginning balance	(1,434)	(1,476)
Currency Translation differences subsidiaries	4	42
Other reserves ending balance	€ (1,430)	€ (1,434)

Other Reserves - Addtional Info

Other Reserves - Addtional Information (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Information On Other Reserves [line items]
Other reserves	€ 34,800	€ 33,172	€ 30,958
Convertible loan [member]
Disclosure Of Information On Other Reserves [line items]
Other reserves	€ 16,631	€ 16,631	€ 16,631

Recoverable Cash Advances - Sum

Recoverable Cash Advances - Summary of Current and Non-current Portion Financial Liabilities (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of financial liabilities [abstract]
Non-Current portion as at 1st January	€ 5,851	€ 4,220
Non-Current portion as at 31 December	4,584	5,851
Current portion as at 1st January	362	371
Current portion as at 31 December	437	362
Total Recoverable Cash Advances at 1st January	6,213	4,590
Total Recoverable Cash Advances 31 December	€ 5,021	€ 6,213

Recoverable Cash Advances - Add

Recoverable Cash Advances - Additional Information (Detail) € in Thousands	12 Months Ended
	Dec. 31, 2022 EUR (€)
Disclosure of financial liabilities [line items]
Contracted recoverable cash advances	€ 25,847
Recoverable cash advances banked	21,800
Existing contracts amounts	€ 2,500
Sales independent reimbursements equivalent percentage of principal amount	30%
Sales independent reimbursements recoverable cash advances	€ 4,800
Sales dependent reimbursements recoverable cash advances	0
Recoverable cash advances related to contracts for exploitation has been abandoned, Received	15,300
Decommitted Contractual Amount	1,533
5915 [member]
Disclosure of financial liabilities [line items]
Contracted recoverable cash advances	910
Contractual amount	€ 200
Percentage of budgeted project cost	70%
Payment equivalent percentage of price received	10%
Payment equivalent percentage of price received	100%
Other contracts [member]
Disclosure of financial liabilities [line items]
Contractual amount	€ 4,800
Percentage of budgeted project cost	200%
Sales independent reimbursements equivalent percentage of principal amount	30%
Other contracts [member] | Bottom of range [member]
Disclosure of financial liabilities [line items]
Percentage of budgeted project cost	45%
Other contracts [member] | Top of range [member]
Disclosure of financial liabilities [line items]
Percentage of budgeted project cost	70%

Recoverable Cash Advances - S_2

Recoverable Cash Advances - Summary of Information on Other Outstanding Advances (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of financial liabilities [line items]
Contractual amount	€ 25,847
Amounts received prior years		€ 16,767
Amounts received	2,458	2,589
Amounts received Cumulated cashed in	21,814
To receive in 2023 and beyond	2,500
Amounts decommitted	1,533
Amount reimbursed (cumulative)	€ 1,926
5915 [member]
Disclosure of financial liabilities [line items]
Project	C-Cathez
Contractual amount	€ 910
Amounts received prior years		910
Amounts received Cumulated cashed in	€ 910
Status	Exploitation
Amount reimbursed (cumulative)	€ 740
6633 [member]
Disclosure of financial liabilities [line items]
Project	C-Cathez
Contractual amount	€ 1,020
Amounts received prior years		1,020
Amounts received Cumulated cashed in	€ 1,020
Status	Exploitation
Amount reimbursed (cumulative)	€ 306
7027 [member]
Disclosure of financial liabilities [line items]
Project	C-Cathez
Contractual amount	€ 2,500
Amounts received prior years		2,500
Amounts received Cumulated cashed in	€ 2,500
Status	Exploitation
Amount reimbursed (cumulative)	€ 675
7502 [member]
Disclosure of financial liabilities [line items]
Project	CAR-T Cell
Contractual amount	€ 2,000
Amounts received prior years		2,000
Amounts received Cumulated cashed in	€ 2,000
Status	Exploitation
Amount reimbursed (cumulative)	€ 100
7685 [member]
Disclosure of financial liabilities [line items]
Project	THINK
Contractual amount	€ 3,496
Amounts received prior years		3,496
Amounts received Cumulated cashed in	€ 3,496
Status	Exploitation
Amount reimbursed (cumulative)	€ 105
8087 [member]
Disclosure of financial liabilities [line items]
Project	CYAD01 - Deplethink
Contractual amount	€ 2,492
Amounts received prior years		2,070
Amounts received Cumulated cashed in	2,070
Amounts decommitted	€ 421
Status	Exploitation
8088 [member]
Disclosure of financial liabilities [line items]
Project	CYAD02 - Cycle1
Contractual amount	€ 3,538
Amounts received prior years		1,500
Amounts received	222	746
Amounts received Cumulated cashed in	2,468
Amounts decommitted	€ 1,071
Status	Exploitation
1910028 [member]
Disclosure of financial liabilities [line items]
Project	CwalityCAR
Contractual amount	€ 2,102
Amounts received prior years		749
Amounts received	1,113	199
Amounts received Cumulated cashed in	2,061
Amounts decommitted	€ 41
Status	Exploitation
8212 [member]
Disclosure of financial liabilities [line items]
Project	CYAD-101
Contractual amount	€ 3,300
Amounts received prior years		825
Amounts received	775	1,370
Amounts received Cumulated cashed in	2,970
To receive in 2023 and beyond	€ 330
Status	Research
8436 [member]
Disclosure of financial liabilities [line items]
Project	Immunicy
Contractual amount	€ 3,394
Amounts received prior years		1,697
Amounts received	348
Amounts received Cumulated cashed in	2,045
To receive in 2023 and beyond	€ 1,349
Status	Research
8516 [member]
Disclosure of financial liabilities [line items]
Project	New engagers
Contractual amount	€ 1,095
Amounts received		€ 274
Amounts received Cumulated cashed in	274
To receive in 2023 and beyond	€ 821
Status	Research

Recoverable Cash Advances - Cer

Recoverable Cash Advances - Certain Terms and Conditions for Recoverable Cash Advances (Detail)	12 Months Ended
	Dec. 31, 2022
5915 [member]
Disclosure of financial liabilities [line items]
Research phase	01/08/08-30/04/11
Percentage of total project costs	70%
Turnover- dependent reimbursment	5%
Turnover-independant reimbursement	€40k in 2012 and €70k each year after
Amount due in case of licensing (per year) resp.Sale	10% with a minimum of 100/Y
6633 [member]
Disclosure of financial liabilities [line items]
Research phase	01/05/11-30/11/12
Percentage of total project costs	60%
Turnover- dependent reimbursment	0.27%
Turnover-independant reimbursement	From €10k to €51k starting in 2013 until 30% of advance is reached
Interest rate accrual	Starting 01/06/13
7027 [member]
Disclosure of financial liabilities [line items]
Research phase	01/11/12-31/10/14
Percentage of total project costs	50%
Turnover- dependent reimbursment	0.33%
Turnover-independant reimbursement	From €25k to €125k starting in 2015 until 30% of advance is reached
Interest rate accrual	Starting 01/01/15
7502 [member]
Disclosure of financial liabilities [line items]
Research phase	01/12/15-30/11/18
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.19%
Turnover-independant reimbursement	From €20k to €50k starting in 2019 until 30% is reached.
Interest rate accrual	Starting 01/12/19
7685 [member]
Disclosure of financial liabilities [line items]
Research phase	01/01/17-31/12/19
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.33%
Turnover-independant reimbursement	From €35k to €70k starting in 2019 until 30% is reached.
Interest rate accrual	Starting 01/01/21
8087 [member]
Disclosure of financial liabilities [line items]
Research phase	01/05/19- 30/06/21
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.22%
Turnover-independant reimbursement	From €20k to €61k starting in 2022 until 30% is reached
Interest rate accrual	Starting 01/07/22
8088 [member]
Disclosure of financial liabilities [line items]
Research phase	01/05/19- 31/12/21
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.21%
Turnover-independant reimbursement	From €25k to €74k starting in 2022 until 30% is reached
Interest rate accrual	Starting 01/01/22
1910028 [member]
Disclosure of financial liabilities [line items]
Research phase	06/06/19- 05/06/22
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.01%
Turnover-independant reimbursement	From €21k to €41k starting in 2022 until 30% is reached
Interest rate accrual	Starting 06/06/22
8212 [member]
Disclosure of financial liabilities [line items]
Research phase	01/01/20- 30/06/23
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.46%
Turnover-independant reimbursement	From €33k to €99k starting in 2024 until 30% is reached
Interest rate accrual	Starting 01/07/23
8436 [member]
Disclosure of financial liabilities [line items]
Research phase	01/11/20- 31/12/23
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.32%
Turnover-independant reimbursement	From €34k to €102k starting in 2024 until 30% is reached
Interest rate accrual	Starting 01/01/24
8516 [member]
Disclosure of financial liabilities [line items]
Research phase	01/04/21-31/03/23
Percentage of total project costs	45%
Turnover- dependent reimbursment	0.10%
Turnover-independant reimbursement	From €11k to 33k starting in 2024 until 30% is reached
Interest rate accrual	Starting 01/04/23

Due Dates of the Financial Li_3

Due Dates of the Financial Liabilities - Aggregate Information Material Contractual Obligations and Payments Due (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Lease liabilities	€ 259	€ 2,965
Pension obligations	13	53
Advances repayable (current and non-current)	5,021	6,213
Total - material contractual obligations	5,293	9,231
Less than one year [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Lease liabilities	141	1,057
Advances repayable (current and non-current)	437	362
Total - material contractual obligations	578	1,419
One to three years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Lease liabilities	118	1,431
Advances repayable (current and non-current)	640	616
Total - material contractual obligations	758	2,047
Three to five years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Lease liabilities	0	477
Advances repayable (current and non-current)	637	740
Total - material contractual obligations	637	1,217
More than five years [member]
Disclosure of maturity analysis for non-derivative financial liabilities [line items]
Pension obligations	13	53
Advances repayable (current and non-current)	3,307	4,495
Total - material contractual obligations	€ 3,320	€ 4,548

Other Non-Current Liabilities -

Other Non-Current Liabilities - Summary of Other Non-Current Liabilities (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Other Non current Liabilities [Abstract]
Onerous contracts - non-current liabilities	€ 124	€ 0
Other non-current liabilities	134	164
Total Other non-current liabilities	€ 258	€ 164

Other Non-Current Liabilities_2

Other Non-Current Liabilities - Additional Information (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Text block [abstract]
Provision for onerous contracts	€ 2,200
Non Provision for onerous contracts	100
Current Provision for onerous contracts	2,113	€ 388
Sublicense fee payable, Noncurrent	€ 100	€ 200

Trade Payables and Other Curr_3

Trade Payables and Other Current Liabilities - Trade Payables and Other Current Liabilities (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Trade and other current payables [abstract]
Total trade payables	€ 4,752	€ 6,611
Other current liabilities
Social security	94	332
Payroll accruals	1,294	1,798
Onerous contracts - current liabilities	2,113	388
Other current grant liabilities	889	1,096
Other current liabilities	710	2,338
Total other current liabilities	5,100	5,952
Total Trade payables and other current liabilities	€ 9,852	€ 12,563

Trade Payables and Other Curr_4

Trade Payables and Other Current Liabilities - Additional Information (Detail) € in Millions	12 Months Ended
	Dec. 31, 2022 EUR (€)
Disclosure of maturity analysis for non-derivative financial liabilities [abstract]
Trade payable settlement description	Trade payables are non-interest-bearing liabilities and are normally settled on 90-day terms. Their decrease is mainly attributable to the timing of the expenses and the related payments
Decrease on social security, payroll accruals	€ 0.7
Decrease in other current liabilites	1.6
Increase in other current liabilites reimbursement of R&D tax credit related	1.9
Accrued Trade Payables	2.8
Adjustments for increase (decrease) in deferred income including contract liabilities	€ 0.2

Financial Instruments - Summary

Financial Instruments - Summary of Carrying and Fair Values of Financial Instruments that are not Reported at Fair Value (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financial Assets
Non-current trade receivables	€ 0	€ 2,209
Other non-current assets	264	262
Short-term investments	0	0
Cash and cash equivalents	12,445	30,018	€ 17,234	€ 39,338
Financial Liabilities
Finance lease liabilities	255	2,632	€ 3,602
RCAs liability	5,021	6,213
Financial liabilities at amortized cost [member]
Financial Liabilities
Finance lease liabilities		2,632
Lease liabilities	255
RCAs liability	5,021	6,213
Trade payables	4,752	6,611
Trade payables and other current liabilities	4,752	6,611
Total	10,028	15,456
Financial assets at amortized cost [member]
Financial Assets
Non-current trade receivables	0	2,209
Other non-current assets	264	262
Trade receivables and other current assets	1,118	668
Short-term investments	0	0
Cash and cash equivalents	12,445	30,018
Total	13,827	33,157
At fair value [member]
Financial Assets
Non-current trade receivables	0	2,209
Other non-current assets	264	262
Trade receivables and other current assets	1,118	668
Short-term investments	0	0
Cash and cash equivalents	12,445	30,018
Total	13,827	33,157
Financial Liabilities
Finance lease liabilities		2,632
Lease liabilities	255
RCAs liability	5,021	6,213
Trade payables	4,752	6,611
Trade payables and other current liabilities	4,752	6,611
Total	€ 10,028	€ 15,456

Financial Instruments - Summa_2

Financial Instruments - Summary of Carrying and Fair Values of Financial Instruments that are Reported at Fair Value (Detail) - EUR (€) € in Thousands	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value		€ 14,679
Contingent consideration and other financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value		14,679
Level I [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value
Level I [member] | Contingent consideration and other financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value
Level II [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value
Level II [member] | Contingent consideration and other financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value
Level III [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value		14,679
Level III [member] | Contingent consideration and other financial liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities, at fair value		€ 14,679

Financial Instruments - Summa_3

Financial Instruments - Summary of Contingent Consideration and Other Financial Liabilities (Detail) - Contingent consideration [Member] - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Opening balance Contingent consideration at 1 January	€ 14,679	€ 15,526
Fair value adjustment	(14,679)	(847)
Closing balance Contingent consideration at 31 December	€ 0	€ 14,679

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail)	Dec. 31, 2021
Disclosure of detailed information about financial instruments [abstract]
Weighted average cost of capital discount rate	13.40%

Financial Instruments - Schedul

Financial Instruments - Schedule of Sensitivity Analysis on Fair Value of Contingent Consideration (Detail)	12 Months Ended
	Dec. 31, 2022
CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	7.50%
CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	4.60%
Phase I [member] | CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	100%
Phase I [member] | CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	100%
Phase I to II [member] | CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	50%
Phase I to II [member] | CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	49%
Phase II to III [member] | CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	28%
Phase II to III [member] | CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	23%
Phase III to BLA [member] | CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	60%
Phase III to BLA [member] | CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	43%
BLA to approval [member] | CYAD-02 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	90%
BLA to approval [member] | CYAD-101 [member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Probablity of success percentage	93%

Changes in Liabilities arisin_3

Changes in Liabilities arising from Financial Activities - Fair Value Measurements Using Significant Unobservable Inputs (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Opening balance at 1 January	€ 0	€ 37
Payments	0	(37)
Closing balance at 31 December	0	0
Opening balance at January 1st	2,632	3,602
New leases	170	129
Payments	(896)	(1,099)
Remeasurement	(1,651)	0
Closing balance at December 31	255	2,632
Opening balance at January 1st	6,213
Closing balance at December 31	5,021	6,213
RCA's [member]
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Opening balance at January 1st	6,213	4,590
Repayments	(230)	(280)
Proceeds - Liability component	485	1,575
Remeasurement	(1,447)	328
Closing balance at December 31	€ 5,021	€ 6,213

Changes in Liabilities arisin_4

Changes in Liabilities arising from Financial Activities - Additional Information (Detail) € in Millions	12 Months Ended
	Dec. 31, 2022 EUR (€)
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Reversed unsettled liabilities, contingent liabilities recognised in business combination	€ 1.4
Fixed Discount Rate [member] | Bottom of range [member] | RCA's [member]
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Effective discount rate applied to financial liability at fair value	0%
Fixed Discount Rate [member] | Top of range [member] | RCA's [member]
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Effective discount rate applied to financial liability at fair value	7%
Variable Discount Rate [member] | Bottom of range [member] | RCA's [member]
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Effective discount rate applied to financial liability at fair value	13%
Variable Discount Rate [member] | Top of range [member] | RCA's [member]
Disclosure of significant unobservable inputs used in fair value measurement of liabilities [line items]
Effective discount rate applied to financial liability at fair value	25%

Revenues - Summary of Revenues

Revenues - Summary of Revenues (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of disaggregation of revenue from contracts with customers [abstract]
Out-licensing revenue	€ 0
Other revenue	0	€ 0	€ 5
Total	€ 0	€ 0	€ 5

Operating Expenses - Summary of

Operating Expenses - Summary of Research and Development Expenses (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Research and Development Expenses [abstract]
Employee expenses	€ 9,062	€ 9,475	€ 8,564
Travel & Living	126	85	116
Clinical study costs	4,280	4,000	5,555
Preclinical study costs	1,233	2,473	1,976
Process development and scale-up	396	770	1,056
Consulting fees	320	568	372
IP filing and maintenance fees	831	353	230
Share-based payments	425	644	927
Depreciation	1,231	1,276	1,511
Rent and utilities	610	670	800
Delivery systems		0	47
Others	415	459	369
Total R&D expenses	€ 18,928	€ 20,773	€ 21,522

Operating Expenses - Additional

Operating Expenses - Additional Information (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Operating Costs And Expenses [line items]
Percentage of increase in general and administrative expenses		6.40%	6.40%
Total Research and Development expenses	€ 18,928	€ 20,773	€ 21,522
Percentage of changes in research and development expense			3%
Changes in general and administrative expenses	600	600
Current onerous contracts provision	2,113	€ 388
Provision for onerous contracts	2,200
CYAD [Member]
Disclosure Of Operating Costs And Expenses [line items]
Current onerous contracts provision	2,200
Provision for onerous contracts	€ 2,100

Operating Expenses - Summary _2

Operating Expenses - Summary of General and Administrative Expenses (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Other General And Administrative Expenses [abstract]
Employee expenses	€ 3,801	€ 3,575	€ 3,363
Share-based payments	1,199	1,529	1,855
Rent	109	50	87
Insurances	1,967	1,642	1,182
Communication & Marketing	239	434	454
Consulting fees	2,870	2,254	1,747
Travel & Living	115	31	91
Post employment benefits	(55)	(7)	19
Depreciation	209	243	320
Other	92	157	197
Total General and administration	€ 10,546	€ 9,908	€ 9,315

Employee Benefit Expenses - Sum

Employee Benefit Expenses - Summary of Employee Expenses (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Employee Benefit Expenses [line items]
Salaries, wages and fees	€ 7,470	€ 7,975	€ 7,139
Executive Committee compensation	3,599	3,115	2,773
Share-based payments	1,624	2,172	2,782
Social security	1,237	1,444	1,487
Post employment benefits	147	251	263
Hospitalisation insurance	226	142	146
Other benefit expense	128	116	138
Total Employee expenses	€ 14,432	€ 15,215	€ 14,727

Employee Benefit Expenses - S_2

Employee Benefit Expenses - Summary Of Staff Full Time Equivalent (Detail) - FTE	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Staff Full Time Equivalent [Line Items]
Employees Full Time Equivalent Units	93.6	112.3	98.3
Research and development [member]
Disclosure Of Staff Full Time Equivalent [Line Items]
Employees Full Time Equivalent Units	82.6	94.1	81.7
General And Administration [Member]
Disclosure Of Staff Full Time Equivalent [Line Items]
Employees Full Time Equivalent Units	11	18.2	16.6

Employee Benefit Expenses - Add

Employee Benefit Expenses - Additional Information (Detail) - Member	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Employee Benefit Expenses [line items]
Percentage of decrease in staff full time equivalent units	16.60%
Percentage of increase in staff full time equivalent units		14.20%
Executives Committee [member]
Disclosure Of Employee Benefit Expenses [line items]
Number of employees	7
Services Agreement [member]
Disclosure Of Employee Benefit Expenses [line items]
Number of employees	3

Other Income And Other Expens_3

Other Income And Other Expenses - Summary of Other Income (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of Detailed Information About Other Operating Income Explanatory [Line Items]
Gain On Sale Of CTMU Activities	€ (5,187)	€ 0	€ 0
Gain on sales of Property, plant & equipment	0	0	35
Remeasurement Of Leases	(169)	0	0
Total Other Income	9,360	4,909	4,731
Other Income [member]
Disclosure of Detailed Information About Other Operating Income Explanatory [Line Items]
Grant income (RCA's)	1,137	2,731	2,311
Grant income (Other)	910	1,448	779
Remeasurement of RCA's	1,447		933
R&D tax credit	462	687	657
Gain On Sale Of CTMU Activities	5,187
Gain on sales of Property, plant & equipment			35
Remeasurement Of Leases	169
Other	€ 48	€ 43	€ 17

Other Income And Other Expens_4

Other Income And Other Expenses - Summary of Other Expenses (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of Detailed Information About Other Operating Expense Explanatory [Line Items]
Loss on disposal of Property, plant and equipment	€ 132	€ 1	€ 10
Amendment fees on license agreement		1,100
Total Other Expenses	338	1,466	114
Other Expenses [Member]
Disclosure of Detailed Information About Other Operating Expense Explanatory [Line Items]
Clinical Development milestone payments			69
Remeasurement of RCA's		328
Loss on disposal of Property, plant and equipment	132	1	10
Loss on disposals of Intangible assets	58
Amendment fees on license agreement		1,104
Other	149	33	35
Total Other Expenses	€ 339	€ 1,466	€ 114

Other Income And Other Expens_5

Other Income And Other Expenses - Additional Information (Detail) - EUR (€) € in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of fair value measurement of assets [line items]
Remeasurement Income on recoverable Cash Advances due to delay on Time to Market Assumptions			€ 1.4	€ 0.9
Amendment fees on license agreement			1.1
Asset Acquisition Consideration Transferred	€ 60
Cellistic [Member]
Disclosure of fair value measurement of assets [line items]
Asset Acquisition Consideration Transferred		€ 6
Proceeds from sales of property, plant and equipment, classified as investing activities		0.6
Goodwill		0.2
Dartmouth College [Member]
Disclosure of fair value measurement of assets [line items]
Clinical Development MileStone Payments to Darmouth				€ 0.1
AMT Autologous CART Program [member]
Disclosure of fair value measurement of assets [line items]
Research and Development Tax Credit			0.7
Federal Belgian Institute For Health Insurance Inami [Member]
Disclosure of fair value measurement of assets [line items]
Additional Grant Income Recognised,Other			0.3
Regional Government [Member] | Eight Zero Six Six Contract Number [member]
Disclosure of fair value measurement of assets [line items]
Additional Grant Income Recognised,Other			1.1
RCA's [member]
Disclosure of fair value measurement of assets [line items]
Additional Grant Income Recognised during Period as a Component of Financial Asset		1.6	2.7
Additional Grant Income Recognised during Period as a Component of Financial Liability		0.5	€ 1.6
Grant Income Recoverable Cash Advances Received		€ 1.1

Change In Fair Value Of Conti_3

Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets - Schedule of Change in Fair Value of Contingent Consideration (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of fair value measurement of liabilities [line items]
Change in fair value of contingent consideration	€ 14,679	€ 847	€ 9,228
Contingent consideration [Member]
Disclosure of fair value measurement of liabilities [line items]
Change in fair value of contingent consideration	€ 14,679	€ 847	€ 9,228

Change In Fair Value Of Conti_4

Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets - Schedule of Impairment of Oncology intangible assets (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Impairment of Oncology intangible assets	€ (35,084)	€ 0	€ 0
Celyad Oncology [Member]
Disclosure of detailed information about intangible assets [line items]
Impairment of Oncology intangible assets	€ (35,084)	€ 0	€ 0

Change In Fair Value Of Conti_5

Change In Fair Value Of Contingent Consideration And Impairment Of Oncology Intangible Assets - Additional Information (Detail) - EUR (€) € in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
AMT Autologous CART Program [member]
Disclosure of fair value measurement of assets [line items]
Delayed Term	1 year
Al logenicCYAD 101CAR T program for mCRC [Member]
Disclosure of fair value measurement of assets [line items]
Delayed Term	1 year
AutologousCYAD 02CAR T program for r r AML MDS [Member]
Disclosure of fair value measurement of assets [line items]
Delayed Term	1 year
Contingent consideration and other financial liabilities [member]
Disclosure of fair value measurement of assets [line items]
Change in Fair value of the Contingent Consideration and Other Financial Liabilities	€ 14.7	€ 0.8

Leases - Summary of Property Pl

Leases - Summary of Property Plant And Equipment Owned And Leased Assets (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Leases [Abstract]
Property, Plant and Equipment owned (excluding right-of-use assets)	€ 86	€ 1,033
Right-of-use assets	223	2,215
Total Property, Plant and Equipment	€ 309	€ 3,248

Leases - Summary of Rights to U

Leases - Summary of Rights to Use Assets (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	€ 2,215
Closing balance	223	€ 2,215
Cost [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	4,020	4,920
Additions	153	91
Disposals	(41)	(41)
Transfers		(950)
Closing balance	872	4,020	€ 4,920
Accumulated depreciation [Member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	(1,805)	(1,916)
Disposals	1,819	41
Transfers		950
Depreciation charge	(663)	(880)
Closing balance	(649)	(1,805)	(1,916)
Property [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	1,744
Depreciation charge	(439)	(454)	(428)
Closing balance	0	1,744
Property [member] | Cost [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	3,025	3,001
Additions	146	24
Disposals	(3,171)
Closing balance	0	3,025	3,001
Property [member] | Accumulated depreciation [Member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	(1,281)	(827)
Disposals	1,721
Depreciation charge	(439)	(454)
Closing balance	0	(1,281)	(827)
Vehicles [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	213
Depreciation charge	(105)	(76)	(75)
Closing balance	83	213
Vehicles [member] | Cost [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	454	429
Additions	7	67
Disposals	(131)	(41)
Closing balance	331	454	429
Vehicles [member] | Accumulated depreciation [Member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	(241)	(165)
Disposals	98	41
Depreciation charge	(105)	(117)
Closing balance	(248)	(241)	(165)
Plant and Equipments [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	258
Depreciation charge	(118)	(309)	(567)
Closing balance	140	258
Plant and Equipments [member] | Cost [member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	541	1,491
Additions		0
Transfers		(950)
Closing balance	541	541	1,491
Plant and Equipments [member] | Accumulated depreciation [Member]
Disclosure of quantitative information about right-of-use assets [line items]
Opening balance	(283)	(924)
Transfers		950
Depreciation charge	(118)	(309)
Closing balance	€ (401)	€ (283)	€ (924)

Leases - Summary of lease expen

Leases - Summary of lease expense (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Depreciation charge of right-of-use assets
Interest on lease liabilities (including in Financial expenses)	€ 150	€ 217	€ 259
Interest on sublease receivable (including in Financial income)	(11)	(26)	(46)
Variable lease payments not included in the measurement of lease liabilities	0
Remeasurement of Leases	(169)
Expenses relating to short-term leases and leases of low-value assets	126	137	166
Total expenses related to leases	758	1,167	1,449
Property [Member]
Depreciation charge of right-of-use assets
Depreciation, right-of-use assets	439	454	428
Vehicles [member]
Depreciation charge of right-of-use assets
Depreciation, right-of-use assets	105	76	75
Plant and Equipments [Member]
Depreciation charge of right-of-use assets
Depreciation, right-of-use assets	€ 118	€ 309	€ 567

Leases - Summary of Cash Outflo

Leases - Summary of Cash Outflow For Leases (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of quantitative information about right-of-use assets [line items]
Total cash outflow for leases	€ 1,172	€ 1,453	€ 1,681

Financial Income and Expenses -

Financial Income and Expenses - Summary of Financial Revenues and Expenses (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [abstract]
Interest finance leases	€ 150	€ 217	€ 260
Interest on overdrafts and other finance costs	33	21	19
Interest on RCAs	14	17	18
Foreign Exchange differences	0	0	136
Finance expenses	198	255	434
Finance income on the net investment in lease	11	26	46
Interest income bank account	1	1	5
Foreign Exchange differences	173	5	0
Other financial income	0	112	166
Finance income	185	144	217
Net Financial result	€ (13)	€ (111)	€ (217)

Financial Income and Expenses_2

Financial Income and Expenses - Additional Information (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [line items]
Net Financial result	€ (13)	€ (111)	€ (217)
Gain/ loss on change in value of foreign exchange difference net of tax	200
Decrease on Interest on Finance Leases	100
Mesoblast Future USD Revenue [member]
Disclosure of detailed information about financial instruments [line items]
Net Financial result	€ 0	100	€ (200)
Gain/ loss on change in value of foreign exchange difference net of tax		€ 100

Income Tax expense - Summary of

Income Tax expense - Summary of Group Reports Income Taxes in the Income Statement (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Major components of tax expense (income) [abstract]
Current tax (expense) / income	€ (65)	€ (10)	€ 0
Deferred tax (expense) / income	0
Total income tax expense in profit or loss	€ (65)	€ (10)	€ 0

Income Tax - Additional Informa

Income Tax - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Applicable tax rate	25%	25%	25%

Income Tax - Schedule of Reconc

Income Tax - Schedule of Reconciliation Between Effective And Theoretical Income Tax (Detail) - EUR (€) € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax expense (income) [abstract]
Loss before tax		€ (40,870)	€ (26,502)	€ (17,204)
Tax disallowed expenses		1,248	1,185	1,092
Share-based payment		€ 1,624	€ 2,172	€ 2,782
Nominal tax rate		25%	25%	25%
Income tax at nominal tax rate	[1]	€ 9,500	€ 5,786	€ 3,333
Deferred tax assets not recognized		(9,565)	(5,796)	(3,333)
Effective tax expense		€ (65)	€ (10)	€ 0
Effective tax rate		0%	0%	0%
[1]The difference in foreign tax rate in the US (25.80%) compared to the Belgian rate (25.00%) is not distinctively disclosed in this table due to non-materiality

Income Tax - Schedule of Reco_2

Income Tax - Schedule of Reconciliation Between Effective And Theoretical Income Tax (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement [Line Items]
Nominal tax rate	25%	25%	25%
United States of America, Dollars
Statement [Line Items]
Nominal tax rate	25.80%
Belgian [Member]
Statement [Line Items]
Nominal tax rate	25%

Deferred Taxes - Schedule of De

Deferred Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets and liabilities, net	€ 79,617	€ 74,562	€ 66,208	€ 61,300
Unrecognised Gross Deferred Tax assets/(liabilities)	79,617	74,562
Unrecognized Net Deferred Tax assets/(liabilities)	79,617	74,562
Intangible asset [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax liabilities	(216)	(2,709)
Unrecognized deferred tax assets and liabilities, net	(216)	(2,709)
Deferred tax asset [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognised Gross Deferred Tax assets/(liabilities)	79,833	77,857
Netting by tax entity	(216)	(3,295)
Unrecognized Net Deferred Tax assets/(liabilities)	79,617	74,562
Deferred tax liabilities [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognised Gross Deferred Tax assets/(liabilities)	(216)	(3,295)
Netting by tax entity	216	3,295
Contingent consideration liabilities [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets	0	3,670
Unrecognized deferred tax assets and liabilities, net	0	3,670
RCA's [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets	1,226	1,503
Unrecognized deferred tax assets and liabilities, net	1,226	1,503
Employee benefits liability [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets	3	13
Unrecognized deferred tax assets and liabilities, net	3	13
Other temporary differences [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets	272
Unrecognized deferred tax liabilities	0	(586)
Unrecognized deferred tax assets and liabilities, net	272	(586)
Tax Losses Carry forward [member]
Disclosure of Deferred Tax Assets And Liabilities [line items]
Unrecognized deferred tax assets	78,332	72,671
Unrecognized deferred tax assets and liabilities, net	€ 78,332	€ 72,671

Deferred Taxes - Schedule of Un

Deferred Taxes - Schedule of Unrecognised Deferred Tax Asset Balance Roll Forward (Detail) - EUR (€) € in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Opening balance	€ 74,562	€ 66,208	€ 61,300
Temporary difference creation or reversal	(606)	(1,014)	(2,981)
Change in Tax-losses carried forward	5,661	8,820	8,064
Closing balance	79,617	74,562	66,208
USA [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Change in tax rate applicable	€ 0	€ 548	€ (176)

Deferred Taxes - Additional Inf

Deferred Taxes - Additional Information (Detail) € in Millions	Dec. 31, 2022 EUR (€)
Deferred tax assets and liabilities [abstract]
Unused tax losses for which no deferred tax asset recognised	€ 312.9

Commitments - Additional Inform

Commitments - Additional Information (Detail) € in Millions, $ in Millions	1 Months Ended			12 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Aug. 31, 2017 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2022 EUR (€)
Disclosure of commitments [line items]
Long Term Lease Liability Undiscounted Lease Payments | €						€ 0.5
Short Term Lease Liability Undiscounted Lease Payments | €						€ 0.3
Amended Asset Purchase Agreement [Member]
Disclosure of commitments [line items]
Development and regulatory milestones			$ 156
Sales Milestone Payments			36.5
Celdara Medical [member] | Amended Asset Purchase Agreement [Member]
Disclosure of commitments [line items]
Development and regulatory milestones			40
Upfront Cash payments			10.5
Single Digit Percentage Payments for Research and Development Funding Received			7.5
Termination Fee Payments for Opt out of Development of any Product			2
Celdara Medical [member] | Amended Asset Purchase Agreement [Member] | Novartis International Pharmaceutical Ltd [Member]
Disclosure of commitments [line items]
Cash Payments in connecton with License Agreement			0.6
Celdara Medical [member] | Amended Asset Purchase Agreement [Member] | Ono Pharmaceutical Co Limited [Member]
Disclosure of commitments [line items]
Cash Payments in connecton with License Agreement			0.9
Celdara Medical [member] | CAR-T NKR-2 product [member] | Amended Asset Purchase Agreement [Member]
Disclosure of commitments [line items]
Clinical And Development Milestone Payments			6
Celdara Medical [member] | Celyad Inc [member] | Amended Asset Purchase Agreement [Member]
Disclosure of commitments [line items]
Payments to acquire New Shares			12.5
Dartmouth College [Member] | Amended Dartmounth License [Member]
Disclosure of commitments [line items]
Non Refundable Non creditable Amendment Fee			2
Dartmouth College [Member] | Celyad Inc [member] | Amended Dartmounth License [Member]
Disclosure of commitments [line items]
Clinical And Regulatory Milestone Payments			1.5
Commercial Milestone Payments			$ 4
Dartmouth College [Member] | Celyad Inc [member] | Amended Dartmounth License [Member] | First Year of Sales [Member]
Disclosure of commitments [line items]
Minimum Net Sales Obligations to be Achieved				$ 10
Dartmouth College [Member] | Celyad Inc [member] | Amended Dartmounth License [Member] | Second Year of Sales [Member]
Disclosure of commitments [line items]
Minimum Net Sales Obligations to be Achieved				40
Dartmouth College [Member] | Celyad Inc [member] | Amended Dartmounth License [Member] | Third Year And Thereafter Sales [Member]
Disclosure of commitments [line items]
Minimum Net Sales Obligations to be Achieved				$ 100
Horizon Discovery Limited [Member]
Disclosure of commitments [line items]
Upfront payments paid		$ 0.1			$ 1
Horizon Discovery Limited [Member] | Celyad Inc [member] | First IND Application [Member] | CYAD 02 [member]
Disclosure of commitments [line items]
Additional Milestone Payments		$ 0.1
Horizon Discovery Limited [Member] | Celyad Inc [member] | First IND Application [Member] | CYAD211 [Member]
Disclosure of commitments [line items]
Additional Milestone Payments	$ 0.2

Relationships with Related Pa_3

Relationships with Related Parties - Summary of Remuneration of Key Management Informations (Detail) € in Thousands											12 Months Ended
	Oct. 05, 2022 shares	Oct. 11, 2021 shares	Dec. 11, 2020 shares	Oct. 25, 2019 Warrant	Oct. 26, 2018 Warrant	Jun. 29, 2017 Warrant	Dec. 08, 2016 Warrant	Nov. 05, 2015 Warrant	May 05, 2014 Warrant	May 06, 2013 Warrant	Dec. 31, 2022 EUR (€) Warrant Member shares	Dec. 31, 2021 EUR (€) Warrant Member shares	Dec. 31, 2020 EUR (€) Member shares
Disclosure of key management personnel compensation [line items]
Number of Executive Committee members | Member											7	7	6
Number of warrants granted	0	874.2	557,050	602,025	426,050	334,400	45,000	353,550	94,400	253,150	594,450	760,800
Number of warrants lapsed | Warrant											(282,252)	(35,000)
Key management personnel of entity or parent [member]
Disclosure of key management personnel compensation [line items]
Short term employee benefits											€ 2,294	€ 1,866	€ 1,349
Post employee benefits											53	45	34
Share-based compensation											790	928	1,110
Other employment costs											143	148	110
Management fees											1,200	1,163	1,335
Total benefits											4,480	4,150	3,939
Executive Committee outstanding fees payables											€ 781	€ 844	€ 660
Number of warrants granted											489,700	395,000	220,000
Number of warrants lapsed											(127,250)	(30,000)	(20,000)
Cumulative outstanding warrants | shares											696,400	921,000	556,000

Relationships with Related Pa_4

Relationships with Related Parties - Summary of Transactions with Non-executive Directors (Detail) € in Thousands											12 Months Ended
	Oct. 05, 2022 shares	Oct. 11, 2021 shares	Dec. 11, 2020 shares	Oct. 25, 2019 Warrant	Oct. 26, 2018 Warrant	Jun. 29, 2017 Warrant	Dec. 08, 2016 Warrant	Nov. 05, 2015 Warrant	May 05, 2014 Warrant	May 06, 2013 Warrant	Dec. 31, 2022 EUR (€) Warrant shares	Dec. 31, 2021 EUR (€) Warrant shares	Dec. 31, 2020 EUR (€) shares
Disclosure of transactions between related parties [line items]
Number of warrants granted	0	874.2	557,050	602,025	426,050	334,400	45,000	353,550	94,400	253,150	594,450	760,800
Non Executive Directors [Member]
Disclosure of transactions between related parties [line items]
Share-based compensation											€ 230	€ 337	€ 396
Management fees											382	373	366
Total benefits											€ 612	€ 710	€ 762
Number of warrants granted											40,000	150,000	80,000
Number of warrants lapsed											60,000	0	30,000
Cumulative outstanding warrants | shares											230,000	340,000	220,000
Management fees payables											€ 93	€ 93	€ 94

Loss Per Share - Calculation of

Loss Per Share - Calculation of Earnings (Loss) Per Share (Detail) - EUR (€) € / shares in Units, € in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings per share [abstract]
Loss of the year attributable to Equity Holders	[1]	€ (40,935)	€ (26,512)	€ (17,204)
Weighted average number of shares outstanding		22,593,956	15,604,014	13,942,344
Earnings per share (non-fully diluted) in €		€ (1.81)	€ (1.7)	€ (1.23)
Outstanding warrants		2,339,646	2,136,556	1,488,006
[1]For 2022, 2021 and 2020, the Company does not have any non-controlling interests and the losses for the year are fully attributable to owners of the parent.

Events after the close of the_2

Events after the close of the fiscal Year - Additional Information (Detail) € in Millions		12 Months Ended
	Jan. 01, 2023 EUR (€)	Dec. 31, 2022 EUR (€)	Jan. 09, 2023 Employees
Cellistic [Member]
Disclosure of non-adjusting events after reporting period [line items]
Proceeds from sales of property, plant and equipment		€ 0.6
Events After Reporting Period [Member]
Disclosure of non-adjusting events after reporting period [line items]
Number of employees | Employees			8
Events After Reporting Period [Member] | Cellistic [Member] | Lease hold improvements and furniture [member]
Disclosure of non-adjusting events after reporting period [line items]
Proceeds from sales of property, plant and equipment	€ 1.3