Exhibit 99.1

“Making the Impossible Possible”

INTERIM FINANCIAL REPORT

H1 2017

REGULATED INFORMATION

This report is prepared in accordance with article 13 of the Belgian Royal Decree of November 14, 2007.

Celyad publishes its Interim Financial Report in French. Celyad has also produced an English translation of this Interim Financial Report for convenience purposes only. In the event of differences of interpretation between the English and the French versions of the Report, the original French version will prevail.

Forward-looking statements

In addition to historical facts or statements of current condition, this report contains forward-looking statements, including statements about the potential safety and feasibility of CYAD-01 cell therapy, including current and planned preclinical and clinical trials for Celyad’s product candidates; the clinical and commercial potential of these product candidates and the adequacy of Celyad’s financial resources; Celyad’s intellectual property portfolio, including plans related thereto; Celyad’s expectations regarding its strategic collaborations and license agreements with third parties, including Novartis, Celdara Medical, and Dartmouth College, and the potential impact of such collaborations on Celyad’s future financial condition; and Celyad’s expected cash burn, which reflect Celyad’s current expectations and projections about future events, and involve certain known and unknown risks, uncertainties and assumptions that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements.

These forward-looking statements are further qualified by important factors and risks, which could cause actual results to differ materially from those in the forward-looking statements, including risks associated with conducting clinical trials; the risk that safety, bioactivity, feasibility and/or efficacy demonstrated in earlier clinical trials or preclinical studies may not be replicated in subsequent trials or studies; risks associated with the timely submission and approval of anticipated regulatory filings; the successful initiation and completion of clinical trials, including its clinical trials for CYAD-01; risks associated with the satisfaction of regulatory and other requirements; risks associated with the actions of regulatory bodies and other governmental authorities; risks associated with obtaining, maintaining and protecting intellectual property, Celyad’s ability to enforce its patents against infringers and defend its patent portfolio against challenges from third parties; risks associated with competition from others developing products for similar uses; risks associated with Celyad’s ability to manage operating expenses; and risks associated with Celyad’s ability to obtain additional funding to support its business activities and establish and maintain strategic business alliances and business initiatives.

A further list and description of these risks, uncertainties and other risks can be found in Celyad’s U.S. Securities and Exchange Commission (SEC) filings and reports, including in the Company’s Annual Report on Form 20-F filed with the SEC on April 4, 2017 and subsequent filings and reports by Celyad. Given these uncertainties, the reader is advised not to place any undue reliance on such forward-looking statements. These forward-looking statements speak only as of the date of publication of this document. The Company expressly disclaims any obligation to update any such forward-looking statements in this document to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statement is based, unless required by law or regulation.

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This management’s discussion and analysis is designed to provide you with a narrative explanation of Celyad SA’s (our, Celyad’s or the Company’s) interim condensed consolidated financial statements. It should be read in conjunction with the unaudited financial information and the notes thereto included in this Interim Financial Report and the audited financial information and the notes thereto included in our 2016 Annual Report available on the Company’s website.

All amounts included herein with respect to the six month periods ended June 30, 2017 and 2016 are derived from our interim condensed consolidated financial statements. The consolidated financial statements for the six months’ period ended June 30, 2017 and 2016 are prepared in accordance with the International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB) and in accordance with the IFRS issued by the IASB as adopted for use in the European Union, and with IAS 34, Interim Financial Reporting.

Except for the historical information contained herein, the matters discussed in this Interim Financial Report may be deemed to be forward-looking statements that involve certain risks and uncertainties. We make such forward-looking statements pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. In this Interim Financial Report, words such as “may,” “will,” “expect,” “anticipate,” “estimate,” “intend,” “plan,” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity, and the development of the industry in which we operate may differ materially from the forward-looking statements contained in this Interim Financial Report. In addition, even if our results of operations, financial condition and liquidity, and the development of the industry in which we operate are consistent with the forward-looking statements contained in this Interim Financial Report, they may not be predictive of results or developments in future periods. We caution readers not to place undue reliance on any forward-looking statements made by us, which speak only as of the date they are made.

Factors that could cause or contribute to these differences include those discussed below and elsewhere in this Interim Financial Report, particularly under the “Risk and Uncertainties” and “Forward-looking statements” sections.

This discussion and analysis is dated as of the date of this Interim Financial Report. We disclaim any obligation, except as specifically required by law, to publicly update or revise any such statements to reflect any change in our expectations or in events, conditions or circumstances on which any such statements may be based, or that may affect the likelihood that actual results will differ from those set forth in the forward-looking statements.

Overview

We are a clinical-stage biopharmaceutical company focused on the identification and development of engineered cell therapies in oncology to address diseases with high unmet medical needs.

We are developing a unique CAR-T cell platform, using Natural Killer Receptor (NKR) transduced on to T lymphocytes. The platform targets a wide range of solid and hematological tumors. Unlike traditional CAR-T cell therapy, which target only one tumor antigen, Natural Killer (NK) cell receptors enable a single receptor to recognize multiple tumor antigens.

Our lead immuno-oncology candidate, CYAD-01 (CAR-T NKG2D), is an engineered CAR T-cell that utilizes the human Natural Killer Receptor NKG2D to recognize multiple ligands on numerous solid and hematological tumors. CYAD-01 triggers cell killing through the binding of NKG2D to any of eight naturally occurring ligands that are known to be overexpressed on more than 80% of tumors.

Preclinical results indicate that CYAD-01 has multiple mechanisms of actions and goes beyond direct cancer cell killing. It inhibits the mechanisms that enable tumors to evade the immune system, activates and recruit anti-tumor immune cells and disrupts the blood supply to the tumor. These mechanisms promote the induction of adaptive immunity, meaning the development of a long-term immune memory against specific tumor antigens of the targeted tumor.

Celyad is developing both autologous and allogeneic approaches. The preclinical research underlying this technology was originally conducted at Dartmouth College by Dr. Charles Sentman and has been published extensively in peer-reviewed publications.

CYAD-01 is currently being investigated in THINK ( TH erapeutic I mmunotherapy with CAR-T NK G2D ) , a Phase I autologous, multiple administrations, dose escalation trial for the treatment of multiple liquid and solid indications. The THINK trial, conducted in the United States and in Belgium, includes two stages: a dose escalation and an extension stage. The dose escalation is being conducted in parallel in solid cancers (colorectal, pancreatic, ovarian, triple negative breast and bladder) and in hematologic (Acute Myeloid Leukemia (AML) and Multiple Myeloma (MM)) cancer groups, while the extension phase will evaluate in parallel each tumor type independently. The dose escalation design includes three dose levels adjusted to body weight: up to 3x108, 1x109 and 3x109 of CAR-T NKG2D cells. At each dose, the patients receive three successive administrations, two weeks apart, of CYAD-01 at the specified dose.

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Major Events During the First Half of 2017

Immuno-oncology Platform

Steady progress has been made in advancing the THINK trial ( TH erapeutic I mmunotherapy with CAR-T NK G2D ) , Celyad’s second clinical trial with its lead product candidate, CYAD-01 (CAR-T NKG2D).

The THINK trial was initiated in late 2016 and is being conducted in the United States and Europe. THINK includes two stages: a dose escalation and an extension stage. The dose escalation stage is being conducted in parallel in five solid cancers (colorectal, pancreatic, ovarian, triple negative breast and bladder) and in two hematologic cancer groups (AML and MM), while the extension phase will evaluate in parallel each tumor type independently. The dose escalation design includes three dose levels adjusted to body weight: up to 3x10 ⁸ , 1x10 ⁹ and 3x10 ⁹ CYAD-01 cells. At each dose, the patients receive three successive administrations, two weeks apart, of CYAD-01 at the specified dose.

All patients enrolled in the second cohort of the solid arm have been dosed successfully, as well as the first patient enrolled in the second cohort of the liquid arm. No adverse events have been reported.

Major clinical milestones achieved in the first half of 2017 include:

In July, Celyad initiated the SHRINK trial ( S tandard C H emotherapy R egimen and I mmunotherapy with CAR-T NK G2D ), the third clinical trial with CYAD-01. SHRINK is an open-label Phase I trial evaluating the safety and clinical activity of multiple doses of CYAD-01, administered concurrently with the neoadjuvant FOLFOX treatment in patients with potentially resectable liver metastases from colorectal cancer.

Cardiovascular Platform

In May, Celyad announced that the U.S. Food and Drug Administration (FDA) had granted Fast Track designation for its C-Cure ^® therapy. The FDA granted Fast Track Development Program designation based on CHART-1 data related to reduction in mortality, hospitalization and improvement of quality of life in patients with chronic heart failure secondary to ischemic cardiomyopathy with baseline Left Ventricular End-Diastolic Volumes (LVEDV) between 200 and 370ml.

Intellectual Property

In January, the U.S. Patent and Trade Office (USPTO) upheld, for a third time, Celyad’s U.S. Patent No. 9,181,527, relating to allogeneic human primary T-cells that are engineered to be TCR-deficient and express a chimeric antigen receptor (CAR). In March, the USPTO rejected another request for a re-examination of the same patent. Celyad’s critical patent remains valid and enforceable.

In May, Celyad obtained a new patent related to its method of treating cancer by administering allogeneic primary human T cells that are engineered to be T-Cell Receptor (TCR)-deficient and to express a CAR.U.S.Patent No. 9,663,763 is the third patent in Celyad’s allogeneic intellectual property portfolio awarded by the USPTO. This new patent claims specifically methods of treating cancer patients with allogeneic TCR-deficient CAR-T immunotherapies. Earlier patents were related to the allogeneic TCR-deficient CAR-T cells per se, and to methods of producing them. The combination of this patent with earlier granted U.S. patents consolidates Celyad’s strong intellectual property (IP) position in the CAR-T field and strengthens the Company’s IP portfolio covering key elements in the allogeneic TCR-deficient CAR-T cells production value chain.

Corporate

In May, Celyad announced a non-exclusive license agreement with Novartis regarding U.S. patents related to allogeneic CAR-T cells. The agreement includes Celyad’s intellectual property rights under U.S. Patent No. 9,181,527 related to allogeneic human primary T-Cells engineered to be TCR-deficient and express a CAR. This agreement is related to two undisclosed targets currently under development by Novartis.

Under the terms of the agreement, Celyad received an upfront payment and is eligible to receive success-based clinical, regulatory and commercial milestone payments in aggregate amounts of up to $96 million. In addition, Celyad is eligible to receive royalties based on net sales of the licensed target associated products at percentages in the single digits. Celyad retains all rights to grant further licenses to third parties for the use of allogeneic CAR-T cells.

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Events Subsequent to Semester-End

In August 2017, Celyad amended its agreements with Celdara Medical, LLC and Dartmouth College related to the CAR-T NKR cell drug product candidates and related technology licensed in January 2015 following the acquisition of OnCyte, LLC. Under the amended agreements, Celyad is to receive an increased share of future revenues generated by these assets, including revenues from its sub-licensees. In return, Celyad paid Celdara Medical LLC and Dartmouth College an upfront payment of $12.5 million (€10.6 million) and issued to Celdara Medical, LLC $12.5 million worth of Celyad’s ordinary shares at an agreed share price of €32.35. The financial effects of the above transactions have not been brought to account in the interim consolidated financial statements of Celyad as of 30 June 2017 and may materially impact the Company’s income statement in the consolidated financial statements at year-end 2017.

Operating Capital Requirements

We believe that our existing cash position is sufficient to continue operating at least for the next 12 months. We also believe that it will enable us to fund our operating expenses and capital expenditure requirements, based on the current scope of our activities, through the first half of 2019. We have based the latter estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. In any event, we will require additional capital to pursue preclinical and clinical activities, obtain regulatory approval for, and commercialize our product candidates.

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3.1. General information

The Company and its subsidiaries (together, the Group) is a clinical-stage biopharmaceutical company focused on the development of specialized CAR-T cell based therapies. The company utilizes its expertise in cell engineering to target cancer.

We are developing a unique CAR-T cell platform, using NKR transduced on to T-lymphocytes. The platform targets a wide range of solid and hematological tumors. Unlike traditional CAR-T cell therapy, which target only one tumor antigen, NK cell receptors enable a single receptor to recognize multiple tumor antigens. Our lead immuno-oncology candidate, CYAD-01 (CAR-T NKG2D), is an engineered CAR T-cell that utilizes the human NKG2D to recognize multiple ligands on numerous solid and hematological tumors.

Celyad 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 Mont-Saint-Guibert, Belgium (company number 0891.118.115). 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 group has four fully owned subsidiaries located in Belgium (Biological Manufacturing Services SA) and in the United States (Celyad Inc.; Corquest Medical, Inc.; and OnCyte, LLC).

These interim consolidated financial statements of Celyad for the six months ended June 30, 2017 (the “interim period”) include Celyad SA and its subsidiaries. These statements were approved by the Audit Committee on August 25, 2017. These statements were subjected to a limited review by BDO Réviseurs d’entreprises SCCRL, the statutory auditor of the Company.

The interim report is available to the public free of charge and upon request to the above-mentioned address or via the Company’s website (http://www.celyad.com/investors).

3.2. Summary of significant accounting policies

The significant accounting policies used for preparing the interim condensed consolidated financial statements are explained below.

3.2.1. Basis of preparation

The interim condensed consolidated financial statements have been prepared in accordance with the IFRS issued by the IASB and in accordance with the IFRS issued by the IASB as adopted for use in the European Union, and with IAS 34, Interim Financial Reporting.They do not include all disclosures that would otherwise be required in a complete set of financial statements and should be read in conjunction with the annual financial statements for the year ended December 31, 2016.

The interim condensed consolidated financial statements have been approved for issue by the Company’s Audit Committee on August 25, 2017.They were subject to a limited review by the statutory auditor, but have not been audited.

The preparation of the Company’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 interim period. However, 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. The principal risks during the interim period have not materially changed from those mentioned in the 2016 Annual Report and subsequent reports and filings made with the SEC, each of which are available on the Company’s website (http://www.celyad.com/investors/regulated-information).

All statements and information relate to the interim period unless otherwise stated.

The interim condensed consolidated interim financial statements are presented in thousands of Euros and all values are rounded to the nearest thousand (€000) except when otherwise indicated.

3.2.2. Accounting policies

The accounting policies and methods applied in these interim condensed consolidated financial statements are the same as those applied in the December 31, 2016 consolidated financial statements. The new or amended IFRS standards issued by the IASB, which became effective January 1, 2017, have had no material effect on the interim condensed consolidated financial statements.There were no new or amended IFRS Standards issued by the IASB as adopted by the European Union which became effective January 1, 2017.

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The Group elected not to early adopt the following new Standards, Interpretations and Amendments, which have been issued by the IASB and the IFRIC, but which are not yet effective as per June 30, 2017 and/or net yet adopted by the European Union as per June 30, 2017 (*):

The company plans to adopt these IFRS Standards on their effective date. The assessment of their impact (in particular, the “principal- agent” application guidance under IFRS 15) is ongoing.

None of the other new standards, interpretations and amendments, which are effective for periods beginning after January 1, 2017, and which have not been adopted early, are expected to have a material effect on the Group’s future financial statements.

3.3. Segment reporting

The chief operating decision-maker (CODM), who is responsible for allocating resources and assessing performance of the Group, has been identified as the Board of Directors that makes strategic decisions.

With the acquisition of OnCyte, LLC and its new technology platform, the management and the CODM have determined that as from 2015, there are two operating segments, respectively the cardiology segment, regrouping the Cardiopoiesis platform, the Corquest Medical, Inc. (Corquest) platform and C-Cathez, and the immuno-oncology segment regrouping all assets developed based on the platform acquired from OnCyte, LLC (OnCyte).

Although the Group is currently active in Europe and in the United States, 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 is also not considered by the Board of Directors for assessing performance or allocating resources.

The CODM is not reviewing assets by segments, hence no segment information per asset is disclosed.As per 30 June 2017, all of the Group’s non-current assets are located in Belgium, except (i) the Corquest intellectual property, valued at €1.5 million which is located in the United States, (ii) the goodwill and In Process Research & Development (IPRD) of OnCyte also located in the United States and (iii) the leasehold improvements made in the offices of Celyad Inc. located in Boston, Massachusetts,USA.

During the first half of 2016, marginal revenue was generated from external customers. All revenue generated related to sales of C-Cath _ez to a limited number of customers. Two-thirds of the research and development (R&D) expenses incurred were i the cardiology segment, with the completion of the CHART-1 clinical trial as the main driver.

During the first half of 2017, the Group has received a non-refundable upfront payment as a result of the Company’s entry into a non-exclusive license agreement with Novartis. R&D expenses associated to our cardiology assets decreased significantly compared to 2016, as a result of our strategy to focus on our immuno-oncology assets.

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3.4 Off-Balance Sheet Arrangements

As of the date of this report and also for the periods presented, we did not have any off-balance sheet arrangements.

3.5 Capital Expenditures

We do not capitalize our research and development expenses until we receive marketing authorization for the applicable product candidate. As of end of June 2017, all research and development expenditures were accounted for as operating expenses.

3.6 Additional disclosure notes to the financial statements

Revenue

Total revenues increased by €3.0 million. In June 2017, the Group has received a non-refundable upfront payment as a result of the Company’s entry into a non-exclusive license agreement with Novartis. This upfront payment, net of the amount paid to the technology inventor Dartmouth College, was fully recognised upon receipt as there are no performance obligations nor subsequent deliverables associated with the payment.

In 2016, revenues were associated to sales of the C-Cath _ez catheter. There were no such sales in the first half of 2017.

We do not expect to generate material revenue unless and until we receive regulatory approval for one of our drug product candidates.

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 our consolidated financial statements.

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Compared to the six months ended June 30, 2016, research and development expenses decreased by €4.3 million during the six-months ended June 30, 2017. This decrease is mostly explained by the following: payroll, clinical study costs and share-based payments. Over the first semester of 2017, most of the R&D efforts of the Company were focused on the development of its immuno-oncology platform, reflecting its strategy on its mid-term positioning. Most of our R&D internal resources are allocated to the continuous development of our lead product candidate, CYAD-01, both on clinical and preclinical efforts. We also emphasize the process development, manufacturing scale-up and automation of our production processes, in preparation of the next anticipated clinical stages of CYAD-01.

General and administrative expenses

General and administrative expenses decreased by €0.5 million over the six-month period ended June 30, 2017 as compared to the six-month period ended June 30, 2016. This variance primarily relates to the decrease the expenses associated to the share-based payments. Share-based payments are non-disbursable expenses related to the share option plan offered to our employees, managers and directors.

Other operating income and expenses

Other operating income and expenses are mostly composed of (i) grant income from subsidies and RCAs (from the Walloon Region and EU FP7 programs), initially recognized at fair value and subsequently measured at amortized cost, and (ii) change in fair values estimates of the contingent consideration associated with future payments owed to Celdara Medical and Dartmouth College During the first half of 2017, there were only limited proceeds received from the Walloon Region.

The management reviewed conservatively the time to commercialization of C-Cure and CYAD-01 based on the clinical development stage of such product candidates. As a consequence, the liabilities associated with C-Cure decreased and those associated with CYAD-01 increased, resulting in a net increase of the liabilities as of 30 June 2017. Company management also reviewed the fair value of the future payments owned to Celdara Medical and Dartmouth College in light of the progress made in the development of the CAR-T platform over the first semester of 2017, leading to an increase of the liability of $1.1 million.

Operating loss

As a result of the foregoing, our operating loss decreased by €3.6 million over the six-month period ending June 30, 2017 as compared to the six-month period ended June 30, 2016, totaling €13.7 million at June 30, 2017.

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Financial income and financial expenses

Financial income is mainly composed of interest income on short term deposits. Financial expenses are mainly composed of currency exchange difference. The interest income is stable compared to 2016. The increase in financial expenses resulted from the depreciation of the U.S. dollar (USD) against the Euro.

Loss for the year

As a result of the foregoing, our loss for the six-month period ended June 30, 2017 decreased by €2.5 million, from €16.9 million as at June 30, 2016 to €14.4 million as at June 30, 2017.

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, 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.

Our liquidity requirements primarily relate to the funding of research & development and general & administrative expenses and working capital requirements. We monitor our risk to a shortage of funds using a monthly liquidity planning tool. Our objective is to maintain a balance between continuity of funding and flexibility through the use of bank deposits and finance leases.

As of December 2016, we funded our operations through several private and public investments for a total of €213.5 million (respectively €42.0 million and €171.5 million). We also received non-dilutive funding from local and European governmental bodies.

There were no capital raises in the first half of 2017. The capital increases, respectively in February and May 2017, were related to the exercise of Company warrants. The Group did not contract for additional bank financing during the first semester of 2017.

Amounts due to the Walloon Region, booked as advances repayable, at June 30, 2017 correspond to the present value of expected future repayments of RCAs received, to support specific development programs related to C-Cure, C-Cath _ez and CYAD-01. We are exposed to liabilities and contingent liabilities as a result of the RCAs we have received from the Walloon Region and the license agreement executed with Celdara Medical, LLC. Out of the RCA contracts pending as of June 30, 2017 totaling €26.7 million, €21.2 million has been effectively paid out.

The following table sets forth our condensed interim consolidated cash flows information for the six-month periods ended June 30, 2017 and 2016.

The cash outflow resulting from operating activities amounted to €14.5 million for the six months ended June 30, 2017 versus €20.8 million for the six months ended June 30, 2016. This decrease primarily resulted from the increase of our revenues associated to the Novartis license agreement and the decrease of our research and development expenses over the first half of 2017 compared to the first half of 2016.

Cash flow from investing activities represented a net cash outflow of €11.2 million for the six months ended June 30, 2017. Cash outflows from investing activities in 2017 were the investments in short-term deposits for a total amount of €45.4 million. Cash inflows over the period amounted to €34.2 million and correspond to the refunding of short-term deposits.

Cash flow from financing activities represented a net cash inflow of €0.3 million in the first half of 2017 compared to €2.0 million for the first half of 2016. The cash inflows in the first half of 2017 resulted from proceeds from exercise of Company warrants in the amount of €0.6 million. Cash outflows for the period corresponded to repayments of bank debt and leasing.

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The variance on the total intangible assets as of June 30, 2017 resulted primarily from currency translation (€3.0 million), the OnCyte IPRD being registered in the accounting books of OnCyte, LLC in USD. Goodwill and OnCyte IPRD are not amortized, but are tested for impairment at least annually and whenever events or changes in circumstances indicate that their value may not be fully recoverable. The amortization expenses for the other intangible assets amounted to €0.4 million as of June 30, 2017.

Cash and cash equivalents in the statement of financial position comprise cash at banks and on hand.

Short-term investments refers to short-term deposits with an original maturity of less than 12 months. The Group has increased the amounts invested in short-term deposits over the first half of 2017.

As of June 30, 2017, share capital amounted to €33,131 represented by 9,525,753 ordinary shares with no nominal value. This balance does not include the outstanding warrants issued by the Company and granted to certain directors, employees and non-employees of Celyad.

There were two capital increases over the course of the first semester 2017 related to warrant exercises:

As of June 30, 2017 all shares issued have been fully paid.

The increase in the non-current portion of the advances repayable reflects revised estimated timing and probability of cash flows for repayment of the recoverable cash advances associated with the contracts related to C-Cure, C-Cathez and CYAD-01 as a result of the outcomes of the respective clinical trials.

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As of June 30, 2017, the maximum undiscounted amount the Group may have to reimburse to the Walloon Region amounts to €18.6 million.

The contingent consideration refers to the acquisition of OnCyte and corresponds to the fair value of the potential future payments due to Celdara Medical, LLC and Dartmouth College pursuant to the agreements signed in January 2015. Future payments are associated with the outcome of the development of the assets acquired and potential future sales estimated through a risk-adjusted net present value.

The decrease of the contingent consideration as of June 30, 2017 resulted from a combination of fair value adjustment and currency translation adjustment. The nominal value of the contingent consideration is in USD and increased by $1.1 million as of June 30, 2017 compared to year-end 2016.

All financial assets and liabilities are considered to have carrying amounts that materially correspond to fair value. Apart from a change in assumptions regarding future cashflows, the underlying variables with respect to the calculation of the fair value of the contingent consideration have not changed compared to year-end 2016 and therefore reference is made to the sensitivity analysis as included in the 2016 financial statements. Also for other fair value disclosures, we refer to the year-end financials.

The compensation amounts presented below, awarded to the members of the Board of Directors and the Executive Management Team of the Company, were recorded as expenses in the period referenced.

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On August 3, 2017, Celyad and its wholly-owned subsidiary OnCyte, LLC, announced the amendment of their agreements with U.S. collaboration partners Celdara Medical LLC and Dartmouth College.

Celyad obtained access to its CAR-T NKR cell drug product candidates and related technology, including technology licensed from Dartmouth College, in January 2015, through its acquisition of OnCyte, LLC from Celdara Medical, LLC, a privately-held U.S. biotechnology company. This portfolio included three autologous CAR-T cell therapy products and an allogeneic T cell platform. Since the acquisition, Celyad has focused on further developing the portfolio and is currently in the preclinical or clinical phase for a number of product candidates.

Under the amended agreements, Celyad will receive an increased share of future revenues generated by these assets, including revenues from its sublicensees. In return, Celyad paid Celdara Medical, LLC and Dartmouth College an upfront payment of $12.5 million (€10.6 million) and issued to Celdara Medical, LLC $12.5 million worth of Celyad’s ordinary shares at an agreed share price of €32.35. The new agreements also give right to Celdara Medical, LLC to a portion of the upfront payments received by Celyad pursuant to its agreements with ONO Pharmaceuticals and Novartis, respectively, in August 2016 and June 2017 in the aggregate amount of $1.5 million. Finally, the service agreement between OnCyte, LLC and Celdara Medical, LLC executed in January 2015 was terminated. The termination of this agreement results in a net savings for Celyad of $0.9 million of amounts originally owed under the agreement.

The financial effects of the above transactions have not been brought to account in the interim consolidated financial statements of Celyad as of June 30, 2017 and may materially impact Celyad’s consolidated financial statements at year-end 2017.

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The following key risks and uncertainties for the Group described here below are those, currently known and specific to us. If any of these risks materialize, our business, financial condition or results of operations could suffer:

This list is not exhaustive, and we recommend that you read the detailed analysis of the risks that the Group faces set out in the Company’s 2016 Annual Report on Form 20-F filed with the SEC on April 4, 2017 and subsequent filings and reports made by Celyad.

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Statutory auditor’s report to the Board of Directors of

CELYAD SA on the review of consolidated interim financial information

for the six-month period ended 30 June 2017

Introduction

We have reviewed the accompanying interim consolidated statement of financial position of CELYAD SA as of 30 June 2017 and the related interim consolidated statements of comprehensive income, cash flows and changes in equity for the six-month period then ended, as well as the explanatory notes. The Board of Directors is responsible for the preparation and presentation of this consolidated interim financial information in accordance with IAS 34 “Interim Financial Reporting”, as adopted by the European Union. Our responsibility is to express a conclusion on this consolidated interim financial information based on our review.

Scope of review

We conducted our review in accordance with International Standard on Review Engagements 2410, “Review of Interim Financial Information Performed by the Independent Auditor of the Entity”. A review of interim financial information consists of making inquiries, primarily of persons responsible for financial and accounting matters, and applying analytical and other review procedures. A review is substantially less in scope than an audit conducted in accordance with International Standards on Auditing and consequently does not enable us to obtain assurance that we would become aware of all significant matters that might be identified in an audit. Accordingly, we do not express an audit opinion.

Conclusion

Based on our review, nothing has come to our attention that causes us to believe that the accompanying consolidated interim financial information is not prepared, in all material respects, in accordance with IAS 34 “Interim Financial Reporting”, as adopted by the European Union.

Brussels, 29 August 2017

BDO Réviseurs d’Entreprises Soc. Civ. SCRL

Statutory auditor

Represented by Bert Kegels

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Financial calendar

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		Exhibit 99.2   Press Release 29 August 2017 07:00 am CEST   Regulated Information

Celyad Reports First Half 2017 Financial Results and

Operational Progress

Celyad’s management will host a conference call at 2pm CEST / 8am EDT today

Mont-Saint-Guibert, Belgium —Celyad (Euronext Brussels and Paris, and NASDAQ: CYAD), a pioneer in the discovery and development of CAR-T cell therapies, today announced its consolidated financial results for the six-month period ending 30 June 2017, prepared in accordance with IFRS as endorsed by the European Union. The full interim financial report is available on Celyad’s website in the Investors section. The half year 2017 consolidated financial statements were subject to a limited review by the company’s statutory auditors.

Operational Highlights of the first half of 2017

Immuno-oncology Platform

Steady progress has been made in advancing the THINK trial ( TH erapeutic I mmunotherapy with CAR-T NK G2D), Celyad’s second clinical trial with its lead product candidate, CYAD-01 (CAR-T NKG2D).

The THINK trial was initiated in late 2016 and is being conducted in the United States and Europe. THINK includes two stages: a dose escalation and an extension stage. The dose escalation stage is being conducted in parallel in five solid cancers (colorectal, pancreatic, ovarian, triple negative breast and bladder) and in two hematologic cancer groups (Acute Myeloid Leukemia (AML) and Multiple Myeloma (MM), while the extension phase will evaluate in parallel each tumor type independently. The dose escalation design includes three dose levels adjusted to body weight: up to 3x10 ⁸ , 1x10 ⁹ and 3x10 ⁹ CYAD-01 cells. At each dose, the patients receive three successive administrations, two weeks apart, of CYAD-01 at the specified dose.

All patients enrolled in the second cohort of the solid arm have been dosed successfully, as well as the first patient enrolled in the second cohort of the liquid arm. No adverse events have been reported.

Major clinical milestones achieved in the first half of 2017 include:

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		Press Release 29 August 2017 07:00 am CEST   Regulated Information

In July, Celyad initiated the SHRINK trial ( S tandard C H emotherapy R egimen and I mmunotherapy with CAR-T NK G2D), the third clinical trial with CYAD-01. SHRINK is an open-label Phase I trial evaluating the safety and clinical activity of multiple doses of CYAD-01, administered concurrently with the neoadjuvant FOLFOX treatment in patients with potentially resectable liver metastases from colorectal cancer.

Dr. Christian Homsy, CEO of Celyad, said: “ We are very pleased with these encouraging preliminary results from the THINK trial, with signs of clinical activity reported in colorectal cancer patients at the first dose administered. With these early data, we feel even more encouraged about the clinical development plan of our lead program, CYAD-01, and look forward to quickly advancing the SHRINK trial. We hope to gather additional evidence of clinical activity in both hematological and solid tumor indications over the second half of 2017.”

Cardiovascular Platform

In May, Celyad announced that the U.S. Food and Drug Administration (FDA) had granted Fast Track designation for its C-Cure ^® therapy. The FDA granted Fast Track Development Program designation based on CHART-1 data related to reduction in mortality, hospitalization and improvement of quality of life in patients with chronic heart failure secondary to ischemic cardiomyopathy with baseline Left Ventricular End-Diastolic Volumes (LVEDV) between 200 and 370ml.

Intellectual Property

In January, the U.S. Patent and Trade Office (USPTO) upheld, for a third time, Celyad’s U.S. Patent No. 9,181,527 relating to allogeneic human primary T-cells that are engineered to be TCR-deficient and express a chimeric antigen receptor (CAR). In March, the USPTO rejected another request for a re-examination of the same patent. Celyad’s critical patent remains valid and enforceable.

In May, Celyad obtained a new patent related to its method of treating cancer by administering allogeneic primary human T cells that are engineered to be T-Cell Receptor (TCR)-deficient and to express a CAR. US Patent n°9,663,763 is the third patent in Celyad’s allogeneic intellectual property portfolio awarded by the USPTO. This new patent claims specifically methods of treating cancer patients with allogeneic TCR-deficient CAR-T immunotherapies. Earlier patents were related to the allogeneic TCR-deficient CAR-T cells per se , and to methods of producing them. The combination of this patent with earlier granted US patents, consolidates Celyad’s strong intellectual property (IP) position in the allogeneic CAR-T field and strengthens the Celyad’s IP portfolio covering key elements in the allogeneic TCR-deficient CAR-T cells production value chain.

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		Press Release 29 August 2017 07:00 am CEST   Regulated Information

Corporate Highlights of the first half of 2017

In May, Celyad announced a non-exclusive license agreement with Novartis regarding US patents related to allogeneic CAR-T cells. The agreement includes Celyad’s intellectual property rights under U.S. Patent No. 9,181,527 related to allogeneic human primary T-Cells engineered to be TCR deficient and express a CAR. This agreement is related to two undisclosed targets currently under development by Novartis.

Under the terms of the agreement, Celyad received an upfront payment and is eligible to receive success-based clinical, regulatory and commercial milestone payments in aggregate amounts of up to $96 million. In addition, Celyad is eligible to receive royalties based on net sales of the licensed target associated products at percentages in the single digits. Celyad retains all rights to grant further licenses to third parties for the use of allogeneic CAR-T cells.

In August 2017, Celyad amended its agreements with Celdara Medical LLC and Dartmouth College related to the CAR-T NK cell drug product candidates and related technology licensed in January 2015 following the acquisition of OnCyte LLC. Under the amended agreements Celyad is to receive an increased share of future revenues generated by these assets, including revenues from its sub-licensees.

In return, Celyad paid Celdara Medical LLC and Dartmouth College an upfront payment of $12.5 million (€10.6 million) and issued to Celdara Medical LLC $12.5 million worth of Celyad’s ordinary shares at a share price of €32.35. The financial effects of the above transactions have not been brought to account in the interim consolidated financial statements of Celyad as of 30 June 2017 and may materially impact Celyad’s income statement in the consolidated financial statements at year end 2017.

Dr. Christian Homsy, CEO of Celyad, continued: “The non-exclusive license agreement contracted with Novartis serves as a key validation of our central intellectual property position in the allogeneic CAR-T field. Finally, the new terms negotiated with Celdara Medical and Dartmouth College should help provide long-term value to Celyad’s shareholders, while the increased ownership of Celdara Medical in Celyad signals a commitment to our development of promising CAR-T cell therapies.”

Patrick Jeanmart, Chief Financial Officer of Celyad, commented: “ Cash and ressource management of our group remains a key focus for Celyad, and this effort has allowed us to meaningfully advance the preclinical and clinical development of our promising CAR-T platform across multiple important indications. We ended the first half of 2017 with € 69 million in cash and short-term deposits which we believe is sufficient to support operating expenses and capital expenditure requirements, based on the current scope of our activities, through the first half of 2019. ”

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		Press Release 29 August 2017 07:00 am CEST   Regulated Information

Celyad’s management will host a conference call at 2pm CEST/8am EDT today Conference Call Details

A conference call will be held on Tuesday 29 August 2017 at 2:00pm (CEST) / 8:00am (EDT) to comment on the mid-year operational and financial results. Christian Homsy, Chief Executive Officer, and Patrick Jeanmart, Chief Financial Officer, will deliver a brief presentation followed by a Q&A session.

Participants are asked to call the assigned numbers approximately five minutes before the conference call begins.

The call can be accessed by dialling the numbers below and using the passcode: 76183347

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		Press Release 29 August 2017 07:00 am CEST   Regulated Information

About Celyad

Celyad is a clinical-stage biopharmaceutical company focused on the development of specialized CAR-T cell based therapies. Celyad utilizes its expertise in cell engineering to target cancer. Celyad’s Natural Killer Receptor based T-Cell (NKR-T) platform has the potential to treat a broad range of solid and hematologic tumors. Its lead oncology candidate, CYAD-01 (CAR-T NKG2D), has been evaluated in a single dose escalation Phase I clinical trial to assess the safety and clinical activity of multiple administrations of autologous CYAD-01 cells in seven refractory cancers including five solid tumors (colorectal, ovarian, bladder, triple-negative breast and pancreatic cancers) and two hematological tumors (acute myeloid leukemia and multiple myeloma). Celyad was founded in 2007 and is based in Mont-Saint-Guibert, Belgium, and Boston, Massachusetts. Celyad’s ordinary shares are listed on the Euronext Brussels and Euronext Paris exchanges, and its American Depository Shares are listed on the NASDAQ Global Market, all under the ticker symbol CYAD.

For more information about Celyad, please visit: www.celyad.com

For more information, please contact:

For Europe: Consilium Strategic Communications

Chris Gardner and Chris Welsh - T: +44 (0)20 3709 5700 - celyad@consilium-comms.com

For France: NewCap

Pierre Laurent and Nicolas Mérigeau - T: + 33(0)1 44 71 94 94 - celyad@newcap.eu

For Belgium: Comfi

Gunther De Backer and Sabine Leclercq - T.: +32 (0)2 290 90 90 - celyad@comfi.be

For the U.S.: Stern Investor Relations

Will O’Connor and Michael Schaffzin - T.: +1 212.362.1200 - celyad@sternir.com

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Forward-looking statements

In addition to historical facts or statements of current condition, this press release contains forward-looking statements, including statements about the potential safety and feasibility of CYAD-01 cell therapy, including current and planned preclinical and clinical trials for Celyad’s product candidates; the clinical and commercial potential of these product candidates and the adequacy of Celyad’s financial resources; Celyad’s intellectual property portfolio, including plans related thereto; Celyad’s expectations regarding its strategic collaborations and license agreements with third parties, including Novartis, Celdara Medical, and Dartmouth College, and the potential impact of such collaborations on Celyad’s future financial condition; and Celyad’s expected cash burn, which reflect Celyad’s current expectations and projections about future events, and involve certain known and unknown risks, uncertainties and assumptions that could cause actual results or events to differ materially from those expressed or implied by the forward-looking statements. These forward-looking statements are further qualified by important factors and risks, which could cause actual results to differ materially from those in the forward-looking statements, including risks associated with conducting clinical trials; the risk that safety, bioactivity, feasibility and/or efficacy demonstrated in earlier clinical trials or preclinical studies may not be replicated in subsequent trials or studies; risks associated with the timely submission and approval of anticipated regulatory filings; the successful initiation and completion of clinical trials, including its clinical trials for CYAD-01; risks associated with the satisfaction of regulatory and other requirements; risks associated with the actions of regulatory bodies and other governmental authorities; risks associated with obtaining, maintaining and protecting intellectual property, Celyad’s ability to enforce its patents against infringers and defend its patent portfolio against challenges from third parties; risks associated with competition from others developing products for similar uses; risks associated with Celyad’s ability to manage operating expenses; and risks associated with Celyad’s ability to obtain additional funding to support its business activities and establish and maintain strategic business alliances and business initiatives. A further list and description of these risks, uncertainties and other risks can be found in Celyad’s U.S. Securities and Exchange Commission (SEC) filings and reports, including in its Annual Report on Form 20-F filed with the SEC on April 4, 2017 and subsequent filings and reports by Celyad. Given these uncertainties, the reader is advised not to place any undue reliance on such forward-looking statements. These forward-looking statements speak only as of the date of publication of this document. Celyad expressly disclaims any obligation to update any such forward-looking statements in this document to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statement is based, unless required by law or regulation.

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