First r/r ALL patient dosed in Europe with Cellectis’ UCART22 product candidate manufactured in-houseCellectis implements CLLS52 for the first time in the clinic with Sanofi’s alemtuzumabCellectis stops enrollment and treatment of patients in the MELANI-01 clinical trial evaluating UCARTCS1 product candidate in r/r MMEncouraging preclinical data on TALEN®-edited MUC1 CAR T-cells presented at the AACR 2023 annual meetingTwo abstracts accepted for oral and poster presentations at the upcoming ASGCT annual meetingCash position1 of 88$ million as of March 31, 2023Conference call scheduled for 8AM ET/2PM CET on May 5, 2023 NEW YORK, May 04, 2023 (GLOBE NEWSWIRE) — Cellectis (the “Company”) (Euronext Growth: ALCLS – NASDAQ: CLLS), a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies, today provided a business update and announced its results for the three-month period ending March 31, 2023. “Cellectis took a notable step forward this quarter with the first patient being dosed in France with our in-house manufactured product candidate UCART22 in the BALLI-01 clinical study. UCART22 is currently the most advanced allogeneic CAR T-cell product in development for relapsed or refractory B-cell acute lymphoblastic leukemia. We believe that our off-the-shelf treatment approach, coupled with our ability to manufacture UCART product candidates entirely in-house, gives us a main advantage on the market: it potentially maximizes the chances for eligible patients to be treated without delay,” said André Choulika, Ph.D., CEO of Cellectis. “Cellectis also announced last month that it implemented the use of Sanofi’s alemtuzumab as a Cellectis Investigational Medicinal Product, coded as CLLS52, as part of the lymphodepletion regimen for UCART22 in the BALLI-01 clinical trial, for UCART123 in the AMELI-01 clinical trial, and for UCART20x22 in the NATHALI-01 clinical trial. This follows the partnership and supply agreements we entered with Sanofi regarding alemtuzumab. “This quarter, Cellectis announced the closing of the global offering of 25 million dollars of its Depository Shares, launched in February – the net proceeds of the global offering and option of the Company is 22.8 million dollars – and in April, the drawdown of the 20 million euros under the Finance Contract for up to 40 million euros credit facility made with the European Investment Bank in December 2022. Cellectis plans to use the net proceeds of the funds to focus on the development of its pipeline of allogeneic CAR T-cell product candidates UCART22, UCART20x22 and UCART123, the Company decided to stop enrollment and treatment of patients with UCARTCS1. Indeed, to accelerate the speed of enrollment of patients in the MELANI-01 study, evaluating UCARTCS1, the Company would have had to invest meaningful amount of resources. To optimize its resources, Cellectis decided to focus its development efforts on the BALLI-01, AMELI-01 and NATHALI-01 studies. “We are excited about the drive in our clinical trials, building on the momentum of our lead product candidates in our pipeline, and the upcoming milestones for 2023.” Pipeline Highlights UCART Clinical Developments Programs BALLI-01 (evaluating UCART22) in relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) UCART22 is an allogeneic CAR T-cell product candidate targeting CD22 and is being evaluated in patients with r/r B-ALL in the BALLI-01 Phase 1/2a clinical study. On April 11, Cellectis announced that the first patient in Europe was dosed in France with its in-house manufactured product candidate UCART22 and completed the 28-day Dose Limiting Toxicity period. UCART22 is currently the most advanced allogeneic CAR T-cell product in development for relapsed or refractory B-cell acute lymphoblastic leukemia. Last December, Cellectis presented updated clinical data on its BALLI-01 clinical trial at a Live Webcast. The BALLI-01 study is now enrolling patients after FCA (fludarabine, cyclophosphamide and alemtuzumab) lymphodepletion. NATHALI-01 (evaluating UCART20x22) in relapsed or refractory B-cell non-Hodgkin lymphoma (r/r NHL) UCART20x22 is Cellectis’ first allogeneic dual CAR T-cell product candidate targeting both CD20 and CD22 and is being evaluated in patients with r/r NHL in the NATHALI-01 Phase 1/2a clinical study. The NATHALI-01 study is now enrolling patients. AMELI-01 (evaluating UCART123) in relapsed or refractory acute myeloid leukemia (r/r AML) UCART123 is an allogeneic CAR T-cell product candidate targeting CD123 and is being evaluated in patients with r/r AML in the AMELI-01 Phase 1 dose-escalation clinical study. On May 17, Cellectis will present clinical data on the AMELI-01 clinical trial in an oral presentation at the American Society of Gene and Cell Therapy (ASGCT) 2023 Annual Meeting. These data were presented in an oral presentation at the 64th American Society of Hematology (ASH) annual meeting last December. Details from the presentation will be available following the event on the Cellectis website at: https://www.cellectis.com/en/investors/scientific-presentations/ The AMELI-01 study is now enrolling patients after FCA (fludarabine, cyclophosphamide and alemtuzumab) lymphodepletion in a two-dose regimen arm. MELANI-01 (evaluating UCARTCS1) in relapsed or refractory multiple myeloma (r/r MM) UCARTCS1 is an allogeneic CAR T-cell product candidate targeting CS1 and is being evaluated in patients with r/r MM in the MELANI-01 Phase 1 dose-escalation clinical study. To accelerate the speed of enrollment of patients in the MELANI-01 study, the Company would have had to invest meaningful amount of resources. To optimize its resources, the Company decided to focus its development efforts on the BALLI-01, AMELI-01 and NATHALI-01 studies and therefore to stop enrollment and treatment of patients in the MELANI-01 study. Research Data & Preclinical Programs TALEN®-edited MUC1 CAR T-cells On April 17, Cellectis released preclinical data on TALEN®-edited MUC1 CAR T-cells at the American Association for Cancer Research (AACR) Annual Meeting 2023. The preclinical data presented in a poster showed the capability of armored allogeneic MUC1 CAR T-cells to excel in the immune suppressive tumor micro-environment suggesting that they could be an effective option in treating relapsed and refractory triple negative breast cancer (TNBC) patients with limited therapeutic options. Poster of the presentation is available on Cellectis’ website: https://www.cellectis.com/en/investors/scientific-presentations/ Multiplex engineering for superior generation of efficient CAR T-cells On May 17, 2023, Cellectis will present preclinical data on multiplex engineering for superior generation of CAR T-cells, at the American Society of Gene and Cell Therapy (ASGCT) 2023 Annual Meeting. Details from the presentation will be available following the event on the Cellectis website at: https://www.cellectis.com/en/investors/scientific-presentations/ Licensed Allogeneic CAR T-cell Development Programs Servier and Allogene: anti-CD19 programs Allogene continues to enroll patients in the industry’s first potentially pivotal Phase 2 allogeneic CAR T clinical trial with ALLO-501A. Allogene announced that the single-arm ALPHA2 trial will enroll approximately 100 r/r large B cell lymphoma (LBCL) patients who have received at least two prior lines of therapy and have not received prior anti-CD19 therapy. Allogene expects to complete enrollment in H1 2024.After the close of the quarter, Allogene announced that pooled data from the Phase 1 ALPHA/ALPHA2 trials of ALLO-501/501A, in r/r LBCL would be presented at the American Society of Clinical Oncology (ASCO) Annual Meeting June 2 – 6, 2023 in Chicago, Illinois. Allogene: anti-BCMA and anti-CD70 programs Allogene presented interim data from its Phase 1 TRAVERSE trial of ALLO-316, its first investigational product candidate for solid tumors, during an oral presentation at the American Association for Cancer Research (AACR) Annual Meeting in April. The ongoing dose escalation study is enrolling patients with advanced or metastatic renal cell carcinoma (RCC) who have progressed on standard therapies that included an immune checkpoint inhibitor and a VEGF-targeting therapy. The data reported to date is primarily from the DL1 and DL2 cohorts. Anti-tumor activity was primarily observed in patients with tumors confirmed to express CD70 (N=10). Among 18 patients evaluable for efficacy, the disease control rate (DCR) was 89%. In the 10 patients whose tumors were known to express CD70, the disease control rate was 100%, which included three patients who achieved partial remission (two confirmed, one unconfirmed). The longest response lasted until month eight. There was a trend toward greater tumor shrinkage in patients with higher levels of CD70 expression. In patients evaluable for safety (N=19), ALLO-316 demonstrated an adverse event profile generally consistent with autologous CAR T therapies. Dose escalation in the TRAVERSE trial is expected to be completed in 2023. During the quarter, data from the Phase 1 UNIVERSAL trial with ALLO-715 for the treatment of r/r multiple myeloma (MM) was published in Nature Medicine. UNIVERSAL is the first allogeneic anti-BCMA CAR T to demonstrate proof-of-concept in MM with response rates that are similar to an approved autologous CAR T therapy. Allogene is evaluating manufacturing processes improvements across its BCMA candidates to achieve optimal performance. Partnerships Cytovia Therapeutics, Inc. (“Cytovia”) On January 20, Cellectis announced that it has amended certain financial terms of the $20 million convertible note issued by its partner, Cytovia Therapeutics, in payment of the upfront collaboration consideration provided for pursuant to the research collaboration and non-exclusive license agreement between Cellectis and Cytovia. The amended and restated note provides for automatic conversion into common stock of Cytovia in the case of certain fundamental transactions pursuant to which Cytovia becomes a public reporting company and for conversion at Cellectis’ option in connection with certain financing transactions, upon a company sale and at final maturity. In each case such conversion is subject to a 9.9% ownership cap, with the balance issuable in the form of pre-funded warrants. Among other changes, the amended and restated note increases the applicable interest rate of the note to 10% per annum, subject to a 10% step up upon the occurrence and continuation of an event of default, provides for the repayment of 50% of the outstanding amount on April 30, 2023 and extends the final maturity date for the repayment of the remaining outstanding amount to June 30, 2023. Corporate Updates Global offering and American Depositary Shares (ADS) On January 4, 2023, Cellectis established an At-The-Market (ATM) Program on Nasdaq. Cellectis has filed a prospectus supplement with the Securities and Exchange Commission (“SEC”), pursuant to which it may offer and sell to eligible investors a maximum gross amount of up to $60.0 million of American Depositary Shares (“ADS”), each representing one ordinary share of Cellectis, nominal value €0.05 per share, from time to time in sales deemed to be an “at the market offering” pursuant to the terms of a sales agreement with Jefferies LLC (“Jefferies”), acting as sales agent. The timing of any sales will depend on a variety of factors. On February 2, 2023 Cellectis announced the launch of the Cellectis Follow-on Offering in which it offered $22 million of its ADS. Jefferies LLC and Barclays Capital Inc. (the “Underwriters”) acted as joint book-running managers for the Global Offering. Pricing occurred on February 2, 2023, at $2.50 per ADS for 8,800,800 ADSs. On February 7, 2023, Cellectis has announced the exercise by the Underwriters of their option (the “Option”) to purchase an additional 1,107,800 ordinary shares (the “Additional Ordinary Shares”) of the Company to be delivered in the form of an aggregate of 1,107,800 ADSs (the “Additional ADSs”). As a consequence, the total number of ordinary shares issued in the form of ADSs amounted to 9,907,800 for the base offering plus the Option exercise bringing the gross proceed to $24.8 million. The aggregate net proceeds to the Company, after deducting underwriting commissions and estimated offering expenses, amounted to approximately $22.8 million. The Company plans to use approximately $17.0 million (€15.6 million) of the net proceeds of the Global Offering to fund the continued clinical development of UCART 123, UCART22 and UCART20x22 and any remainder for working capital and other general corporate purposes. Calyxt and Cibus Merger Agreement On January 13, 2023, Calyxt and Cibus, and the other parties thereto entered into the definitive Merger Agreement under which Calyxt and Cibus will merge in an all-stock transaction. Under the terms of the Merger Agreement, Calyxt will issue shares of its common stock to Cibus shareholders in an exchange ratio such that upon completion of the merger, Calyxt shareholders are expected to own approximately 5% of the combined company, subject to adjustments permitted by the Merger Agreement. The Boards of Directors of both companies unanimously approved the Calyxt Merger. Concurrent with the execution of the merger agreement, certain officers of Calyxt, all of Calyxt’s directors, and Cellectis executed support agreements in favor of the Calyxt Merger. On March 1, 2023, as stated in the Merger Agreement, Calyxy’s Board authorized the grant of 3,487,503 RSUs to all employees. These awards will vest upon completion of the Transactions, and accordingly, the expense associated with these awards will be recognized over the period from the date of grant to the estimated closing date of the Transactions. Consequently, after the completion of the Transaction, and subject to the issuance of some or all of such RSUs, Cellectis will own approximately 2.4% of Calyxt. Cellectis currently holds a 48.2 % equity interest in Calyxt. Following the closing of the merger, Cellectis is expected to own approximately 2.4% of the equity interests of the combined company. Warrant agreement with the European Investment Bank On April 4, Cellectis announced it entered into the warrant agreement (the “Warrant Agreement”) and finalized the related ancillary documents required under the credit facility with the European Investment Bank (“EIB”) for up to €40 million previously announced on December 28, 2022. The Company also announced the drawdown of the first tranche of €20 million (“Tranche A”) under the Finance Contract, that has been disbursed by the EIB in early April 2023. Cellectis plans to use the proceeds of Tranche A towards the development of its pipeline of allogeneic CAR T-cell product candidates: UCART22, UCART20x22, UCART123. Financial results The interim condensed consolidated financial statements of Cellectis, which consolidate the results of Calyxt, Inc. of which Cellectis owned approximately 48.2% of outstanding shares of common stock (as of March 31, 2023), have been prepared in accordance with International Financial Reporting Standards, as issued by the International Accounting Standards Board (“IFRS”). We present certain financial metrics broken out between our two reportable segments – Therapeutics and Plants – in the appendices of this Q1 2023 financial results press release. On January 13, 2023, Calyxt, Cibus Global LLC (Cibus) and certain other parties named therein, entered into an Agreement and Plan of Merger (the “Merger Agreement”), pursuant to which, subject to the terms and conditions thereof, Calyxt and Cibus will merge in an all-stock transaction (the “Calyxt Merger”). As a consequence of the foregoing, Calyxt meets the “held-for-sale” criteria specified in IFRS 5 and has been classified as a discontinued operation. Cash: As of March 31, 2023, Cellectis, excluding Calyxt, had $88 million in consolidated cash, cash equivalents, and restricted cash. This compares to $95 million in consolidated cash, cash equivalents and restricted cash as of December 31, 2022. This difference mainly reflects $30 million of cash out, which include $6 million of payments for R&D expenses, $4 million for SG&A suppliers, $15 million for staff costs, $4 million for rents and taxes, $1 million of reimbursement of the “PGE” loan and a $23 million net cash inflow from the capital raise closed in February. Based on the current operating plan, Cellectis (excluding Calyxt) anticipates that the cash and cash equivalents as of March 31, 2023 will fund Cellectis’ operations into the third quarter of 2024. Revenues and Other Income: Consolidated revenues and other income were $3.6 million for the three months ended March 31, 2023 compared to $3.8 million for the three months ended March 31, 2022. The slight decrease of $0.2 million between the three months ended March 31, 2023, and 2022 reflects the recognition of two milestones related to Cellectis’ agreement with Cytovia for $1.5 million in 2022 while recognition of revenues in 2023 is not material and was almost fully offset by an increase of the research tax credit for $1.0 million in addition to the recognition of a BPI R&D grant of $0.3 million. R&D Expenses: Consolidated R&D expenses were $21.1 million three months ended March 31, 2023 compared to $26.6 million for the three months ended March 31, 2022. The $5.5 million decrease was primarily attributable to (i) a $2.6 million decrease in personal expenses due to departures not replaced (ii) a $3.0 million decrease in purchases, external expenses and other (from $13.8 million in 2022 to $10.8 million in 2023) mainly explained by internalization of our manufacturing and quality activities to support our R&D pipeline. SG&A Expenses: Consolidated SG&A expenses were $5.0 million for the three months ended March 31, 2023 compared to $6.1 million for the three months ended March 31, 2022. The $1.1 million decrease primarily reflects (i) a $0.9 million decrease in purchases, external expenses and other (from $3.7 million in 2022 to $2.9 million in 2023) mainly explained by the implementation of our new enterprise resource planning (ERP) software in 2022 (ii) a $0.2 million decrease in personal expenses. Net income (loss) from discontinued operations: The $1.7 million decrease of net loss from discontinued operations between the three-month period ended March 31, 2022 and 2023 is primarily driven by (i) the decrease of $2.6 million of R&D expenses (from $3.2 million in 2022 to $1.3 in 2023) and SG&A expenses (from $2.9 million in 2022 to $2.2 million in 2023) partially offset by (i) the increase of $0.7 million of net financial loss and (ii) the increase of $0.2 million of other operating expenses. Net Income (loss) Attributable to Shareholders of Cellectis including Calyxt: The consolidated net loss attributable to shareholders of Cellectis was $30.1 million (or $0.58 per share) for the three months ended March 31, 2023, of which $27.8 million was attributed to Cellectis continuing operations, compared to $31.9 million (or $0.70 per share) for the three months ended March 31, 2022, of which $28.3 million was attributed to Cellectis continuing operations. This $1.8 million decrease in net loss between the three months of 2023 and 2022 was primarily driven by (i) a $5.3 million decrease of research and development, (ii) a decrease of $1.7 million of loss from discontinued operations, (iii) a $1.3 million decrease of SG&A expenses partially offset by (i) an increase in net financial loss of $5.3 million primarily due to the decrease of the fair value of Cytovia’s convertible note on March 31, 2023 of $4.6 million compared to a $7.9 million on December 31, 2022, (ii) a decrease of $0.2 million of revenues and other income, (iii) an increase of other operating expenses of $0.6 million, (iv) a decrease of $0.4 million in loss attributable to non-controlling interests due to the decrease in Calyxt’s net loss. Adjusted Net Income (Loss) Attributable to Shareholders of Cellectis: The consolidated adjusted net loss attributable to shareholders of Cellectis was $28.1 million (or $0.55 per share) for the three months ended March 31, 2023, of which $26.2 million is attributed to Cellectis, compared to a net loss of $29.3 million (or $0.64 per share) for the three months ended March 31, 2022, of which $26.0 million was attributed to Cellectis. Please see “Note Regarding Use of Non-IFRS Financial Measures” for reconciliation of GAAP net income (loss) attributable to shareholders of Cellectis to adjusted net income (loss) attributable to shareholders of Cellectis. We currently foresee focusing our cash spending at Cellectis for 2023 in the following areas: Supporting the development of our pipeline of product candidates, including the manufacturing and clinical trial expenses of UCART123, UCART22, UCART 20×22 and potential new product candidates, andOperating our state-of-the-art manufacturing capabilities in Paris (France), and Raleigh (North Carolina, USA); andContinuing strengthening our manufacturing and clinical departments. CELLECTIS S.A.(unaudited)STATEMENT OF CONSOLIDATED FINANCIAL POSITION($ in thousands, except per share data) As of December 31, 2022 March 31, 2023 ASSETS Non-current assets Intangible assets718 713 Property, plant, and equipment63,621 61,708 Right-of-use assets44,275 43,436 Non-current financial assets8,791 8,185 Total non-current assets 117,406 114,042 Current assets Trade receivables772 1,120 Subsidies receivables14,496 18,245 Other current assets9,078 9,703 Cash and cash equivalent and Current financial assets97,697 88,162 Total current assets 122,043 117,231 Total assets held for sale21,768 20,135 TOTAL ASSETS 261,216 251,408 LIABILITIES Shareholders’ equity Share capital2,955 3,487 Premiums related to the share capital583,122 608,086 Currency translation adjustment(28,605) (28,542)Retained earnings(333,365) (439,220)Net income (loss)(106,139) (30,074)Total shareholders’ equity – Group Share117,968 113,735 Non-controlling interests7,973 6,754 Total shareholders’ equity125,941 120,489 Non-current liabilities Non-current financial liabilities20,531 19,625 Non-current lease debts49,358 48,285 Non-current provisions2,390 2,540 Total non-current liabilities 72,279 70,450 Current liabilities Current financial liabilities5,088 5,188 Current lease debts7,872 8,181 Trade payables21,456 22,324 Deferred revenues and deferred income59 342 Current provisions477 1,011 Other current liabilities13,179 6,094 Total current liabilities 48,131 43,140 Total liabilities related to asset held for sale14,864 17,328 TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY 261,216 251,408 CELLECTIS S.A.STATEMENT OF CONSOLIDATED OPERATIONS – First three months(unaudited)($ in thousands, except per share data) For the three-month period ended March 31, 2022 * 2023 Revenues and other income Revenues 1,665 139 Other income 2,135 3,420 Total revenues and other income 3,800 3,559 Operating expenses Cost of revenue (385) (334)Research and development expenses (26,601) (21,081)Selling, general and administrative expenses (6,063) (4,964)Other operating income (expenses) 21 (611)Total operating expenses (33,028) (26,990) Operating income (loss) (29,228) (23,431) Financial gain (loss) 912 (4,402) Income (loss) from continuing operations (28,316) (27,833)Income (loss) from discontinued operations (6,441) (4,691)Net income (loss) (34,757) (32,525)Attributable to shareholders of Cellectis (31,911) (30,074)Attributable to non-controlling interests (2,846) (2,450)Basic net income (loss) attributable to shareholders of Cellectis per share ($/share) (0.70) (0.58) Diluted net income (loss) attributable to shareholders of Cellectis per share ($/share) (0.70) (0.58) Basic net income (loss) attributable to shareholders of Cellectis per share ($ /share) from discontinued operations (0.08) (0.04) Diluted net income (loss) attributable to shareholders of Cellectis per share ($ /share) from discontinued operations (0.08) (0.04) * These amounts reflect adjustments made in connection with the presentation of the discontinued operation CELLECTIS S.A.DETAILS OF KEY PERFORMANCE INDICATORS BY REPORTABLEFirst three months(unaudited) For the three-month period endedMarch 31, 2022 For the three-month period endedMarch 31, 2023$ in thousands Plants (discontinued operations)TherapeuticsTotal reportable segments Plants (discontinued operations)TherapeuticsTotal reportable segments External revenues 32 1,665 1,697 42 139 180 External other income – 2,135 2,135 – 3,420 3,420 External revenues and other income 32 3,800 3,832 42 3,559 3,600 Cost of revenue (0)(385)(385) – (334)(334)Research and development expenses (2,878)(26,601)(29,479) (2,165)(21,081)(23,246)Selling, general and administrative expenses (3,216)(6,063)(9,279) (1,336)(4,964)(6,300)Other operating income and expenses 43 21 65 (139)(611)(750)Total operating expenses (6,050)(33,028)(39,078) (3,640)(26,990)(30,630)Operating income (loss) before tax (6,019)(29,228)(35,247) (3,598)(23,431)(27,029)Net financial gain (loss) (422)912 490 (1,093)(4,402)(5,495)Net income (loss) from discontinued operations (6,441) (6,441) (4,691) (4,691)Net income (loss) (6,441)(28,316)(34,757) (4,691)(27,833)(32,525)Non-controlling interests 2,846 – 2,846 2,450 – 2,450 Net income (loss) attributable to shareholders of Cellectis (3,595)(28,316)(31,911) (2,241)(27,833)(30,074)R&D non-cash stock-based expense attributable to shareholder of Cellectis (11)1,680 1,669 85 1,103 1,188 SG&A non-cash stock-based expense attributable to shareholder of Cellectis 342 636 979 274 517 791 Adjustment of share-based compensation attributable to shareholders of Cellectis 332 2,316 2,648 359 1,620 1,979 Adjusted net income (loss) attributable to shareholders of Cellectis (3,263)(26,000)(29,263) (1,882)(26,213)(28,095)Depreciation and amortization (708)(4,934)(5,641) 6 (4,456)(4,450)Additions to tangible and intangible assets 363 581 945 – 245 245 Note Regarding Use of Non-IFRS Financial Measures Cellectis S.A. presents adjusted net income (loss) attributable to shareholders of Cellectis in this press release. Adjusted net income (loss) attributable to shareholders of Cellectis is not a measure calculated in accordance with IFRS. We have included in this press release a reconciliation of this figure to net income (loss) attributable to shareholders of Cellectis, which is the most directly comparable financial measure calculated in accordance with IFRS. Because adjusted net income (loss) attributable to shareholders of Cellectis excludes Non-cash stock-based compensation expense—a non-cash expense, we believe that this financial measure, when considered together with our IFRS financial statements, can enhance an overall understanding of Cellectis’ financial performance. Moreover, our management views the Company’s operations, and manages its business, based, in part, on this financial measure. In particular, we believe that the elimination of Non-cash stock-based expenses from Net income (loss) attributable to shareholders of Cellectis can provide a useful measure for period-to-period comparisons of our core businesses. Our use of adjusted net income (loss) attributable to shareholders of Cellectis has limitations as an analytical tool, and you should not consider it in isolation or as a substitute for analysis of our financial results as reported under IFRS. Some of these limitations are: (a) other companies, including companies in our industry which use similar stock-based compensation, may address the impact of Non-cash stock- based compensation expense differently; and (b) other companies may report adjusted net income (loss) attributable to shareholders or similarly titled measures but calculate them differently, which reduces their usefulness as a comparative measure. Because of these and other limitations, you should consider adjusted net income (loss) attributable to shareholders of Cellectis alongside our IFRS financial results, including Net income (loss) attributable to shareholders of Cellectis. RECONCILIATION OF IFRS TO NON-IFRS NET INCOME – First Quarter(unaudited)($ in thousands, except per share data) For the three-month period ended March 31, 2022 * 2023 Net income (loss) attributable to shareholders of Cellectis (31,911) (30,074)Adjustment: Non-cash stock-based compensation expense attributable to shareholders of Cellectis 2,648 1,979 Adjusted net income (loss) attributable to shareholders of Cellectis (29,263) (28,095) Basic Adjusted net income (loss) attributable to shareholders of Cellectis ($/share) (0.64) (0.55)Basic adjusted earnings from discontinued operations attributable to shareholders of Cellectis ($ /share) (0.07) (0.04) Weighted average number of outstanding shares, basic (units) 45,486,477 51,452,348 Diluted Adjusted net income (loss) attributable to shareholders of Cellectis ($/share) (0.64) (0.55)Diluted Adjusted net income (loss) attributable to shareholders of Cellectis ($/share) from discontinued operations (0.07) (0.04) Weighted average number of outstanding shares, diluted (units) 45,486,477 51,452,348 *These amounts reflect adjustments made in connection with the presentation of the discontinued operation About Cellectis Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. Cellectis utilizes an allogeneic approach for CAR-T immunotherapies in oncology, pioneering the concept of off-the-shelf and ready-to-use gene-edited CAR T-cells to treat cancer patients, and a platform to make therapeutic gene editing in hemopoietic stem cells for various diseases. As a clinical-stage biopharmaceutical company with over 23 years of experience and expertise in gene editing, Cellectis is developing life-changing product candidates utilizing TALEN®, its gene editing technology, and PulseAgile, its pioneering electroporation system to harness the power of the immune system in order to treat diseases with unmet medical needs. Cellectis’ headquarters are in Paris, France, with locations in New York, New York and Raleigh, North Carolina. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). For more information, visit www.cellectis.com. Follow Cellectis on social media: @cellectis, LinkedIn and YouTube Forward-looking Statements This press release contains “forward-looking” statements within the meaning of applicable securities laws, including the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by words such as “anticipate,” “believe,” “intend”, “expect,” “plan,” “scheduled,” “could,” “would” and “will,” or the negative of these and similar expressions. These forward-looking statements, which are based on our management’s current expectations and assumptions and on information currently available to management, including information provided or otherwise publicly reported by our licensed partners. Forward-looking statements include statements about advancement, timing and progress of clinical trials (including with respect to patient enrollment and follow-up), the timing of our presentation of data and submission of regulatory filings, the adequacy of our supply of clinical vials, the operational capabilities at our manufacturing facilities, the sufficiency of cash to fund operations, the adequacy and continuity of supply of clinical supply and alemtuzumab, the ability of an anti-CD52 as alemtuzumab to improve any efficacy and the potential benefit of UCART product candidates. These forward-looking statements are made in light of information currently available to us and are subject to numerous risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. With respect to our cash runway, our operating plans, including product development plans, may change as a result of various factors, including factors currently unknown to us. Furthermore, many other important factors, including those described in our Annual Report on Form 20-F and the financial report (including the management report) for the year ended December 31, 2022 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, as well as other known and unknown risks and uncertainties may adversely affect such forward-looking statements and cause our actual results, performance or achievements to be materially different from those expressed or implied by the forward-looking statements. Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons why actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future. For further information, please contact: Media contact: Pascalyne Wilson, Director, Communications, +33 (0)7 76 99 14 33, media@cellectis.com Investor Relation contacts: Arthur Stril, Chief Business Officer, +1 (347) 809 5980, investors@cellectis.com Ashley R. Robinson, LifeSci Advisors, +1 617 430 7577 1 Cash position includes cash, cash equivalents and restricted cash. Restricted cash was $5 million as of March 31, 2023. Attachment Q1 2023 PR(1)