CLLS

Lasme-cel: Pivotal Phase 2 in r/r B-ALL (BALLI-01) FDA RMAT designation received for lasme-cel Full Phase 1 clinical data from the BALLI-01 trial presented at EHA 2026 Pivotal Phase 2 first interim analysis expected in Q4 2026 Eti-cel: Phase 1 in r/r NHL (NATHALI-01) Translational data from the NATHALI-01 trial highlighting key drivers of response presented at EHA 2026 Full Phase 1 dataset expected in Q4 2026 Cash, cash equivalents and fixed-term deposits of $169 million as of June 30, 20261 provide runway into Q4 2027. NEW YORK, Aug. 06, 2026 (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 financial results for the second quarter 2026 ending June 30, 2026. "The lasme-cel and eti-cel clinical results presented at EHA 2026 are promising for patients with relapsed or refractory B-cell malignancies. We are also pleased to have received RMAT designation from the FDA for lasme-cel, which recognizes its potential to address an unmet medical need in B-ALL. We remain focused on advancing new options for people whose disease has returned or stopped responding to available therapies," said André Choulika, Ph.D., Co-Founder and Chief Executive Officer at Cellectis. ___________________________________ 1  Cash, cash equivalents and fixed-term deposits include restricted cash of $2.3 million as of June 30, 2026 classified as current and non-current financial assets and fixed-term deposits of $131.1 million as of June 30, 2026, classified as current financial assets. Allogeneic CAR-T Pipeline Lasme-cel in relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) – BALLI-01 The Pivotal Phase 2 BALLI-01 trial is ongoing. In June 2026, Cellectis received FDA Regenerative Medicine Advanced Therapy (RMAT) designation for lasme-cel for treatment of r/r CD22 positive B-ALL. This designation was granted based on the BALLI-01 clinical data, demonstrating promising efficacy and a manageable safety profile. It reflects the FDA's recognition of the potential of lasme-cel to address the unmet medical need faced by patients with r/r B-ALL. In June 2026, Cellectis presented full Phase 1 data from the BALLI-01 trial at an oral presentation at the European Hematology Association (EHA) 2026 Annual Congress. 45 patients were treated in third line and beyond (3L+), including 15 at the recommended Phase 2 dose (RP2D), and 7 in the target Phase 2 population. Heavily pretreated population: A median of 5 prior lines of therapy in the target Phase 2 population (range 2–11); 82% had received prior blinatumomab, 56% a CD22-directed antibody drug conjugate (ADC), 53% CD19 CAR-T, and 47% a prior hematopoietic stem cell transplantation (HSCT). Efficacy Data (target Phase 2 population) 100% overall response rate (ORR) (7/7) 57% complete remission/complete remission with incomplete count recovery (CR/CRi) (4/7), of whom 75% were minimal residual disease (MRD)-negative All responding patients proceeded to HSCT Safety Data The therapy demonstrated a manageable safety profile, with grade ≥ 3 cytokine release syndrome (CRS) and Immune effector cell-associated neurotoxicity syndrome (ICANS), each occurring in 4% of patients. Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) ≥ grade 3 occurred in 2% of patients. All events resolved. In June 2026, the UK Medicines and Healthcare products Regulatory Agency (MHRA) approved the initiation of the Phase 2 study of BALLI-01 in the UK. In July 2026, enrollments in the Phase 2 BALLI-01 study in France, Italy and Spain have been authorized. The first interim analysis for the pivotal Phase 2 of the BALLI-01 trial is expected in Q4 2026. Eti-cel in relapsed or refractory non-Hodgkin lymphoma (r/r NHL) – NATHALI-01 The Phase 1 NATHALI-01 trial is ongoing. In June 2026, Cellectis presented translational data highlighting the key drivers of response at a poster presentation at the EHA 2026 annual congress. As of the February 2026 data cutoff, 14 patients with r/r B-NHL had been treated across three dose levels. Heavily pretreated population: median of 3 prior lines of therapy; 93% had received prior CD19-directed CAR-T therapy. Efficacy Data (optimal dose cohort, n=8) 88% ORR 63% complete response (CR) rate Higher alemtuzumab exposure was associated with a lower inflammatory homeostatic milieu prior to eti-cel infusion, enhanced eti-cel expansion, and higher response rates. Responders demonstrated sustained low-level interleukin-2 (IL-2) secretion versus non-responders. These findings support a weight-based alemtuzumab dosing regimen, currently under investigation to optimize lymphodepletion. Subcutaneous low-dose IL-2 is also being evaluated to further enhance eti-cel expansion and response. Cellectis expects to present the full Phase 1 dataset in Q4 2026. Partnerships AstraZeneca - Joint Research and Collaboration Agreement Activities are continuing under the Joint Research and Collaboration Agreement with AstraZeneca, which leverages Cellectis’ gene editing expertise and manufacturing capabilities to develop up to 10 novel cell and gene therapy products for areas of high unmet medical need, including oncology, immunology and rare genetic disorders. Servier (through its sublicensee Allogene) – Anti-CD19 CAR-T In July 2026, Allogene announced that the FDA has granted RMAT and Fast Track designations to cema-cel for the treatment of adult patients with large B-cell lymphoma (LBCL) who, at the completion of first-line (1L) therapy, are in complete or partial response suitable for observation but test positive for minimal residual disease (MRD). Cema-cel is a product candidate licensed to Servier under the License, Development and Commercialization Agreement signed by and between les Laboratoires Servier and Institut de Recherches Internationales Servier (“Servier”) and Cellectis (the “Servier Agreement”) and sublicensed by Servier to Allogene in certain territories. Allogene – Anti-CD70 CAR-T In July 2026, Allogene announced the publication of complete Phase 1 data from the TRAVERSE study of ALLO-316 in advanced or metastatic renal cell carcinoma (RCC) in the Journal of Clinical Oncology. Allogene announced that ALLO-316 achieved a 31% confirmed response rate with the recommended Phase 2 regimen in patients with Stage IV RCC with high CD70 expression, and that the safety profile was manageable with proactive diagnostic and management strategies effective in mitigating IEC-HS.2 Allogene’s investigational allogeneic CAR-T oncology products utilize Cellectis technologies. The anti-CD70 program is licensed exclusively from Cellectis by Allogene and Allogene holds global development and commercial rights to this program. ___________________________________ 2  IEC-HS includes the preferred terms immune effector cell-associated HLH-like syndrome and Hemophagocytic lymphohistiocytosis. Corporate Updates Annual Shareholders’ Meeting On June 25, 2026, Cellectis held a Shareholders General Meeting at the Biopark auditorium in Paris, France. At the meeting, during which approximately 56% of voting rights were exercised, resolutions 1 through 29 were adopted, while resolution 30 was rejected, consistent with the recommendations of the Board of Directors. The detailed results of the vote and the resolutions are available on Cellectis’ website: https://www.cellectis.com/en/investors/general-meetings/ Financial Results Cash, cash equivalent and fixed-term deposits: As of June 30, 2026, Cellectis had $169 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current financial assets. The Company believes its cash, cash equivalents and fixed-term deposits will be sufficient to fund its operations into Q4 2027. This compares to $211 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current financial assets as of December 31, 2025. The $42 million change was primarily driven by payments to suppliers of $26.9 million, payroll-related payments (salaries, bonuses and social charges) totaling $28.5 million, lease liability payments of $5.4 million, repayments of $2.7 million under the “PGE” loan and capital expenditures of $0.5 million, partially offset by $16.8 million of cash received from customers and $4.9 million of interest received from our financial and cash-equivalent investments. We currently foresee focusing our cash spending at Cellectis in supporting the development of our pipeline of product candidates, including the manufacturing and clinical trial expenses of lasme-cel, eti-cel and potential new product candidates, and operating our state-of-the-art manufacturing capabilities in Paris (France) and Raleigh (North Carolina). Revenues and Other Income: Consolidated revenues and other income were $14.5 million for the six-month period ended June 30, 2026, compared to $30.2 million for the six-month period ended June 30, 2025. The $15.8 million decrease between the six-month periods ended June 30, 2025 and 2026 was primarily attributable to a $16.4 million decrease in revenues mainly driven by the level of activities performed under the Research Plans of the AstraZeneca Joint Research Collaboration Agreement in the first half of 2026. It was partially offset by a $0.6 million increase, which was mainly attributable to a higher research tax credit resulting from increased eligible R&D expenses, as well as favorable foreign exchange effects. R&D Expenses: Consolidated R&D expenses were $52.2 million for the six-month period ended June 30, 2026, compared to $45.0 million for the six-month period ended June 30, 2025. The $7.2 million increase was primarily driven by (i) a $4.5 million increase in personnel expenses reflecting changes in our R&D headcount and higher stock-based compensation expense associated with awards granted in 2026, whose grant-date fair value increased due to a higher underlying share price, and (ii) a $3.7 million increase in purchases and external expenses, primarily attributable to higher clinical development costs related to our BALLI-01 and NATHALI-01 studies, partially offset by (iii) a $1.0 million decrease in depreciation and amortization expenses. SG&A Expenses: Consolidated SG&A expenses were $11.3 million for the six-month period ended June 30, 2026, compared to $9.8 million for the six-month period ended June 30, 2025. The $1.5 million increase was primarily attributable to a $1.2 million increase in personnel expenses, mainly reflecting higher stock-based compensation expense associated with awards granted in 2026, whose grant-date fair value increased due to a higher underlying share price. Purchases and external expenses increased slightly by $0.2 million, from $4.4 million in 2025 to $4.7 million in 2026. Net financial gain (loss): The consolidated net financial gain for the six-month period ended June 30, 2026 was $9.2 million, compared to a $18.1 million net financial loss for the six-month period ended June 30, 2025. The $27.3 million difference reflects a $5.0 million increase in financial income and a $22.3 million decrease in financial expenses. The $5.0 million increase in financial income was primarily attributable to (i) a $7.0 million increase in non-cash gains recognized from fair value measurements, mainly reflecting an $8.7 million gain on the fair value measurement of the Tranche A, B and C warrants issued to the European Investment Bank ("EIB") in the six months ended June 30, 2026, compared with a $1.2 million gain in the same period in 2025, partially offset by (ii) a $1.7 million decrease in interest income earned on cash, cash equivalents and financial assets, and (iii) a $0.4 million decrease in foreign exchange gains. The $22.3 million decrease in financial expenses was primarily attributable to a $22.8 million decrease in foreign exchange losses mainly resulting from the appreciation of the US dollar against the euro. Net Loss Attributable to Shareholders of Cellectis: Consolidated net loss attributable to shareholders of Cellectis was $39.6 million (or a $0.39 net loss per share) for the six-month period ended June 30, 2026, compared to a $41.9 million net loss (or a $0.42 net loss per share) for the six-month period ended June 30, 2025. The $2.3 million decrease in net loss was mainly due to (i) a $27.3 million improvement in net financial result, from a net financial loss of $18.1 million as of June 30, 2025 to a net financial gain of $9.2 million as of June 30, 2026, partly offset by (ii) a $24.9 million increase in operating loss. Adjusted Net Loss Attributable to Shareholders of Cellectis: Consolidated adjusted net loss attributable to shareholders of Cellectis was $35.6 million (or a $0.35 net loss per share) for the six-month period ended June 30, 2026, compared to a net loss of $39.6 million (or a $0.40 net loss per share) for the six-month period ended June 30, 2025. The interim condensed consolidated financial statements of Cellectis have been prepared in accordance with International Financial Reporting Standards, as issued by the International Accounting Standards Board (“IFRS”). 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. 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® Accounting Standards. 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 Accounting Standards.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 financial statements prepared in accordance with IFRS Accounting Standards, 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 performance as reported under IFRS Accounting Standards. 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 statements of consolidated operations prepared in accordance with IFRS Accounting Standards, including Net income (loss) attributable to shareholders of Cellectis. About Cellectis     Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. The company 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 develop gene therapies in other therapeutic indications. With its in-house manufacturing capabilities, Cellectis is one of the few end-to-end gene editing companies that controls the cell and gene therapy value chain from start to finish. Cellectis’ headquarters are in Paris, France, with locations in New York and Raleigh, NC. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). To find out more, visit www.cellectis.com and follow Cellectis on LinkedIn and X. Cautionary Statement 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 “expected,” “foresee,” “may,” “potential,” “promising,” “will” or the negative of these and/or similar expressions. These forward-looking statements 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 the potential of the pivotal Phase 2 BALLI-01 trial to be registrational phases, the advancement, timing and progress of clinical trials, the timing of our presentation of data, the potential safety and efficacy of our product candidates, the potential benefits of RMAT designation, the sufficiency of cash to fund operations, the potential benefit of our product candidates and technologies, and the outcomes of our collaboration agreements, including with AstraZeneca, Servier, and Allogene. These forward-looking statements are made in light of information currently available to us and are subject to significant risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. Actual results, performance or events may differ materially from those projected in any forward-looking statement. Many important factors may adversely affect such forward-looking statements and cause actual results to differ from those in any forward-looking statement, including, without limitation, inconclusive clinical trial results or clinical trials failing to achieve one or more endpoints; early data not being repeated in ongoing or future clinical trials; promising preclinical data not yielding positive clinical results; failures to secure required regulatory approvals; regulatory developments in the United States and European Union and its member countries, and other countries; disruptions from failures by third-parties on whom we rely in connection with our clinical trials; delays or negative determinations by regulatory authorities; changes or increases in oversight and regulation; increased competition, including within the hemato-oncology field, which may affect our assessment of the relative strategic priority of our various research and development programs; manufacturing delays or problems; inability to achieve enrollment targets; disagreements with our collaboration partners or failures of collaboration partners to pursue product candidates; legal challenges, including product liability claims or intellectual property disputes or disputes with respect to a licensing agreement; any failure to achieve potential benefits or our licensing agreements with licensees or to enter into future arrangements; the ability and willingness of licensees to actively pursue development activities under our collaboration agreements; commercialization factors, including regulatory approval and pricing determinations; disruptions to access to raw materials or starting material; delays or disruptions at our in-house manufacturing facilities; proliferation and continuous evolution of new technologies; capital resource constraints; the rate and degree of market acceptance of, and demand for, our product candidates; dislocations in the capital markets; and our ability to attract and retain key scientific and management personnel. Particular caution should be exercised when interpreting results from Phase 1 studies and results and interim data relating to a small number of patients – such results should not be viewed as predictive of future results. 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 as amended and in our annual financial report (including the management report) for the year ended December 31, 2025 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, which are available on the SEC’s website at www.sec.gov, 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 on Cellectis, please contact:              Media contacts:              Pascalyne Wilson, Director, Communications, + 33 (0)7 76 99 14 33, Patricia Sosa Navarro, Chief of Staff to the CEO, +33 (0)7 76 77 46 93,[email protected] Investor Relations contact:           Arthur Stril, Chief Financial Officer & Chief Business Officer, [email protected] Attachment PRESS RELEASE_Q2_earnings_EN

NEW YORK, June 11, 2026 (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, presents final Phase 1 data from the BALLI-01 clinical trial evaluating lasme-cel, a CD22 directed allogeneic CAR-T therapy, in patients with relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL), and preliminary data from the NATHALI-01 study evaluating eti-cel, a dual CD20 and CD22 directed CAR-T in relapsed/refractory B-cell non Hodgkin lymphoma (r/r B-NHL), at the European Hematology Association (EHA) 2026 Annual Congress. BALLI-01 clinical trial evaluating lasme-cel in r/r B-ALL - Oral Presentation The BALLI-01 final Phase 1 data will be presented as an oral presentation by Nitin Jain, M.D., Professor of Medicine, Department of Leukemia at the University of Texas MD Anderson Cancer Center in Houston, TX. 45 patients in third line and beyond (3L+) were treated in the BALLI-01 study. 15 patients were treated at the recommended Phase 2 dose and 7 in the target Phase 2 population. Patients were heavily pretreated with those in the target Phase 2 population receiving a median of 5 prior lines of therapy (Range 2-11). Almost all patients were previously treated with blinatumumab (82%) and were also heavily exposed to CD19 CAR-T (53%), CD22-directed antibody-drug conjugate (ADC) (56%) and many had a prior hematopoietic stem cell transplantation (HSCT) (47%). Final Phase 1 data In the target Phase 2 population An overall response rate (ORR) of 100% (7/7) was achieved with a complete remission/complete remission with incomplete count recovery (CR/CRi) rate of 57% (4/7). Of these, 75% achieved minimal residual disease negative (MRD-ve) status. All patients subsequently proceeded to HSCT. Lasme-cel demonstrated a manageable safety profile Cytokine release syndrome (CRS) ≥ grade 3 occurred in 4% of patients. Immune effector cell-associated neurotoxicity syndrome (ICANS) ≥ grade 3 occurred in 4% of patients. Immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) ≥ grade 3 occurred in 2% of patients. All CRS, ICANS, and IEC-HS resolved. “These final Phase 1 results are particularly meaningful for a patient population that has very limited treatment options” said Nitin Jain, M.D., Professor of Medicine, Department of Leukemia at UT MD Anderson. “Being able to achieve deep remissions in these patients and allowing them to subsequently receive an HSCT is promising. We look forward to accelerating accrual into the ongoing Pivotal Phase 2 study and bringing this treatment to patients.” The Pivotal Phase 2 BALLI-01 trial is open for recruitment. Eligible patients and treating physicians are encouraged to visit BALLI-01 (NCT04150497) or contact Cellectis at [email protected] for information and participating sites. The first interim analysis is expected in Q4 2026. Oral Presentation: Safety and efficacy of UCART22 in heavily pretreated patients with relapsed or refractory CD22+ B-cell acute lymphoblastic leukemia (B-ALL): results of the Phase 1 BALLI-01 trial Date/Time:  Saturday, June 13 at 5:15 - 6:30pm, local timeSession Title: Advances in the treatment of lymphoblastic leukemiaSession Room: K1Abstract Number: 4689 Note: presentation slides will be uploaded to Cellectis’ website concurrently with the live presentation. NATHALI-01 clinical trial evaluating eti-cel in r/r B-NHL - Poster Presentation The NATHALI-01 preliminary data on the role of alemtuzumab in optimizing responses will be presented as a poster by Professor Emmanuel Bachy, M.D., Ph.D., Department of Hematology, Hospices Civils de Lyon, France. Eti-cel is a highly differentiated product being the first allogeneic dual CAR-T targeting both CD20 and CD22, for patients with r/r B-NHL. As of the February 2026 data cutoff, 14 patients with r/r B-NHL had been treated across three dose levels, in a heavily pre-treated population with a median of 3 prior lines of therapy, 93% of whom had received prior CD19-directed CAR-T therapy, and all of whom presented with stage IV disease at baseline. In the optimal dose cohort, ORR and complete response (CR) were 88% and 63%, respectively. The analysis identified a positive correlation between alemtuzumab exposure and clinical outcomes: higher alemtuzumab exposure created a favorable lower inflammatory homeostatic milieu prior to eti-cel infusion and was associated with enhanced eti-cel expansion and higher response rates. Additionally, responders maintained sustained low-level interleukin 2 (IL-2) secretion when compared to non-responders. These findings provide a scientific rationale for the implementation of a weight-based alemtuzumab dosing regimen, currently under investigation to optimize lymphodepletion. Additionally, subcutaneous low-dose IL-2 is being investigated to further enhance eti-cel expansion and treatment response. “These encouraging data demonstrate that not only can eti-cel drive responses in a very difficult-to-treat population, but that by optimizing exposure to alemtuzumab we may be able to create a favorable environment for CAR-T expansion and persistence." said Professor Emmanuel Bachy, M.D., Ph.D., Department of Hematology, Hospices Civils de Lyon, France. The NATHALI-01 study is open for recruitment with the full Phase 1 clinical data expected in Q4 2026. Poster Presentation: Alemtuzumab exposure and sustained IL-2 drive UCART20x22 expansion and clinical response in adults with relapsed or refractory B-cell non-Hodgkin lymphoma: NATHALI-01 study Date/Time:  Saturday, June 13 at 6:45 - 7:45pm, local timeSession: Poster Session 2Poster Number: 4758 Note: poster presentation will be uploaded to Cellectis’ website at the opening of the poster session. About Cellectis Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. The company 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 develop gene therapies in other therapeutic indications. With its in-house manufacturing capabilities, Cellectis is one of the few end-to-end gene editing companies that controls the cell and gene therapy value chain from start to finish. Cellectis’ headquarters are in Paris, France, with locations in New York and Raleigh, NC. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). To find out more, visit www.cellectis.com and follow Cellectis on LinkedIn and X. Cautionary Statement 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 “can,” “expected,” ”look-forward,” “may” or the negative of these and/or similar expressions. These forward-looking statements are based on our management’s current expectations and assumptions and on information currently available to management. Forward-looking statements include statements about the potential of the pivotal Phase 2 BALLI-01 trial to be a registrational phase, the 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 sufficiency of cash to fund operations, the potential benefit of our product candidates. These forward-looking statements are made in light of information currently available to us and are subject to significant risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. Among these are significant risks that the BALLI-01 Phase 1 data may not be validated by data from later stage of clinical trials and that our product candidate may not receive regulatory approval for commercialization. Particular caution should be exercised when interpreting results from Phase 1 studies and results relating to a small number of patients – such results should not be viewed as predictive of future results. Furthermore, many other important factors, including those described in our Annual Report on Form 20-F as amended and in our annual financial report (including the management report) for the year ended December 31, 2025 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, which are available on the SEC’s website at www.sec.gov, 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 on Cellectis, please contact: Media contacts: Pascalyne Wilson, Director, Communications, + 33 (0)7 76 99 14 33, [email protected] Patricia Sosa Navarro, Chief of Staff to the CEO, +33 (0)7 76 77 46 93 Investor Relations contact: Arthur Stril, Chief Financial Officer & Chief Business Officer, [email protected] Attachment Press release_data_EHA_2026_ENGLISH

Pivotal Phase 2 with lasme-cel in r/r B-ALL (BALLI-01 trial) Pivotal Phase 2 first interim analysis expected in Q4 2026 BLA submission anticipated in 2028 Phase 1 with eti-cel in r/r NHL (NATHALI-01 trial) Full Phase 1 dataset expected in Q4 2026 Innovation Preclinical data on TALE-based epigenetic editing, a non-DNA cutting approach, to be presented at ASGCT Servier (through Allogene): Interim pivotal data reported from the ALPHA3 trial of cema-cel (n=24) 58.3% of patients in the cema-cel arm achieved MRD negativity versus 16.7% in the observation arm Favorable safety profile: no cases of CRS, ICANS, GvHD, or Treatment-Related Serious Adverse Events Study accrual expected to be completed by year-end 2027, interim EFS analysis in mid-2027, primary EFS analysis in mid-2028 Cash, cash equivalents and fixed-term deposits of $188 million as of March 31, 20261 provide runway into Q4 2027 NEW YORK, May 11, 2026 (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 financial results for the first quarter 2026, ending March 31, 2026 and provided a business update. "The interim pivotal data published by Allogene on cema-cel, a product originally developed by Cellectis as UCART19, are a proud validation of our vision: that allogeneic, off-the-shelf cell therapy candidates could deliver transformative outcomes for cancer patients. We believe this approach has the potential to dramatically expand access to CAR-T beyond what autologous therapies can reach today” said André Choulika, Ph.D., Co-Founder and Chief Executive Officer of Cellectis. “As we look ahead to Q4 2026, with the expected interim pivotal Phase 2 data for lasme-cel in relapsed or refractory B-ALL, and the full Phase 1 dataset for eti-cel in relapsed or refractory NHL, Cellectis is approaching its own defining moment. We are excited about what lies ahead." ________________________________ 1 Cash, cash equivalents and fixed-term deposits include restricted cash of $2.3 million as of March 31, 2026 classified as current and non-current financial assets and fixed-term deposits of $150.6 million as of March 31, 2026, classified as current financial assets. Allogeneic CAR-T Pipeline Lasme-cel in relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) - BALLI-01 The Pivotal Phase 2 BALLI-01 trial is ongoing. Phase 1 data highlights : 100% ORR in the target Phase 2 population 83% overall response rate (ORR) at recommended Phase 2 dose (RP2D) In target Phase 2 population: all patients became eligible to transplant Favorable safety profile: low rates of ≥ grade 3 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) at 2.5% and 5% respectively 14.8 months median overall survival (OS) in patients who achieved minimal residual disease (MRD)-negative complete remission with incomplete hematology recovery (CR/CRi) The first interim analysis for the pivotal Phase 2 of the BALLI-01 trial is expected in Q4 2026 (n=40). Cellectis anticipates submitting a Biologics License Application (BLA) in 2028. Eti-cel in relapsed or refractory non-Hodgkin lymphoma (r/r NHL) – NATHALI-01 The Phase 1 NATHALI-01 trial is ongoing. Preliminary Phase 1 data highlights: At current dose level: 88% ORR, 63% complete response (CR) rate after 2+ prior lines of therapy 93% of subjects had prior CD19 CAR-T Cellectis expects to present the full Phase 1 dataset in Q4 2026, including results from the low dose interleukin-2 (IL-2) combination cohorts. TALE-based epigenetic editing platform to turn genes off without altering DNA On April 27, 2026, Cellectis announced new research on a TALE-based epigenetic editing approach, that does not cut or permanently modify the DNA sequence, making it a potentially safer alternative for genome editing, at the American Society of Gene and Cell Therapy (ASGCT) annual meeting, that is taking place on May 11-15, 2026. Key data highlights: Cellectis developed TALEM (Transcription Activator-Like Effector-based epigenetic Modulators), engineered fusion proteins that precisely target genomic loci to switch genes on or off through epigenetic editing, without cutting or permanently modifying the DNA sequence. Using a high-throughput screening system capable of rapidly assembling and testing hundreds of TALEM candidates, Cellectis demonstrated >90% stable gene silencing across two distinct targets: a gene highly expressed in liver cells and a gene implicated in T-cell exhaustion, a key challenge in cancer immunotherapy. The abstract is live on the ASGCT website. The poster will be available on Cellectis’ website on May 13, 2026 at 5 pm ET. Partnerships AstraZeneca – Joint Research and Collaboration Agreement Activities are continuing under the Joint Research and Collaboration Agreement with AstraZeneca, which leverages Cellectis’ gene editing expertise and manufacturing capabilities to develop up to 10 novel cell and gene therapy products for areas of high unmet medical need, including oncology, immunology and rare genetic disorders. Servier (through its sublicensee Allogene) – Anti-CD19 CAR-T Cema-cel is a product candidate licensed to Servier under the License, Development and Commercialization Agreement signed by and between les Laboratoires Servier and Institut de Recherches Internationales Servier (“Servier”) and Cellectis (the “Servier Agreement”) and sublicensed by Servier to Allogene in certain territories. On April 13, 2026, Cellectis highlighted the interim pivotal data announced by Allogene, from Allogene’s sponsored ALPHA3 trial evaluating cema-cel in first-line consolidation for large B-cell lymphoma (LBCL). Cema-cel is derived from the UCART19 product initially developed by Cellectis. Key data highlights reported by Allogene: The futility analysis (n=24) showed that 58.3% of patients in the cema-cel arm achieved MRD negativity versus 16.7% in the observation arm, a 41.6% absolute difference. Allogene reported that based on specific benchmark literature, a difference of 25-30% in the MRD clearance could translate into meaningful clinical benefit at study completion. The cema-cel treatment was generally well-tolerated, with most patients (10/12) managed on an outpatient basis post-infusion and no cases of CRS, ICANS, graft-versus-host disease (GvHD), treatment-related Serious Adverse Events and no hospitalizations for treatment-related Adverse Events. Allogene announced that study accrual is anticipated to be complete by the end of 2027 and that it anticipates an interim Event-Free Survival (EFS) analysis in mid-2027 and the primary EFS analysis in mid-2028. If positive, Allogene announced that these results could support a BLA submission. Under the Servier Agreement, Cellectis is eligible to up to $340 million in development and sales milestones as well as low double-digit royalties on sales of licensed CD19 products, including cema-cel developed in LBCL. Iovance In May 2026, Iovance announced that a Phase 1/2 trial, IOV-GM1-201, is enrolling using IOV-4001, a PD-1 inactivated TIL therapy, in previously treated advanced melanoma and non-small cell lung cancer (NSCLC). Subsequent events On April 20, 2026, Life Technologies Corporation (“LTC”), a subsidiary of Thermo Fisher, purported to terminate license agreements between LTC and Cellectis in 2014, which grant Cellectis non-exclusive rights under certain patents, the Halle Patent Therapeutic License, the Halle Patent Research License, and the GeneArt and Seamless Cloning Patent Therapeutic License (the « LTC Agreements »). This purported termination follows TFS’s allegations that we failed to comply with our obligations under the LTC Agreements, as previously disclosed. Simultaneously therewith, LTC commenced an arbitration before the American Arbitration Association, naming Cellectis S.A. and Cellectis Bioresearch, Inc. as Respondents. LTC’s arbitration demand alleges that Cellectis has breached the LTC License Agreements by underpaying sublicense royalties and otherwise failing to comply with our obligations under the LTC Agreements. According to us, this termination is invalid and LTC’s claims under this arbitration demand are without merit. Financial Results Cash: As of March 31, 2026, Cellectis had $188 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current financial assets. The Company believes its cash, cash equivalents and fixed-term deposits will be sufficient to fund its operations into Q4 2027. This compares to $211 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current financial assets as of December 31, 2025. The $23 decrease was mainly driven by cash inflows of $13.0 million from revenue and $2.9 million of interest received from our financial and cash-equivalent investments, offset by payments to suppliers of $14.5 million, payroll-related payments (wages, bonuses and social charges) totaling $18.6 million, lease liability payments of $3.4 million, repayment of $1.4 million under the “PGE” loan, and capital expenditures of $0.3 million. We currently foresee focusing our cash spending at Cellectis in supporting the development of our pipeline of product candidates, including the manufacturing and clinical trial expenses of lasme-cel, eti-cel and potential new product candidates, and operating our state-of-the-art manufacturing capabilities in Paris (France) and Raleigh (North Carolina). Revenues and Other Income: Consolidated revenues and other income were $7.5 million for the three-month period ended March 31, 2026, compared to $12.0 million for the same period in 2025. This $4.5 million decrease between the three-month periods ended March 31, 2025 and 2026 was mainly attributable to a $4.9 million decrease in revenues driven by the evolution of activities performed under the AZ JRCA. R&D Expenses: Consolidated R&D expenses were $27.2 million for the three-month period ended March 31, 2026, compared to $21.9 million for the same period in 2025, representing an increase of $5.3 million, mainly due to a $3.6 million increase in personnel expenses and a $2.0 million increase in purchases and external expenses. SG&A Expenses: Consolidated SG&A expenses were $5.6 million for the three-month period ended March 31, 2026, compared to $4.7 million for the same period in 2025. The $0.9 million increase was mainly due to a $0.4 million increase in stock-based compensation expenses and related social charges as well as a $0.4 million increase in purchases and other expenses. Net financial gain (loss): We had a consolidated net financial gain of $7.4 million for the three-month period ended March 31, 2026, compared to a $3.9 million net financial loss for the three-month period ended March 31, 2025. This $11.4 million increase in net financial result reflects a $5.6 million increase in financial income and a $5.8 million decrease in financial expenses. The rise in financial income was mainly attributable to (i) a $4.5 million increase in non-cash gains on fair value measurements primarily explained by a $6.5 million gain on the fair value measurement of the Tranches A, B and C of EIB warrants in the three months ended March 31, 2026 compared to a $1.8 million gain in the three months ended March 31, 2025, (ii) a $2.0 million increase in foreign exchange gains, partially offset by (iii) a $1.1 million decrease in income from cash, cash equivalents and financial assets. The decrease in financial expenses was mainly due to a (i) $6.5 million decrease in foreign exchange loss, partially offset by (ii) a $0.2 million increase in interests on financial liabilities. Net Income (loss) Attributable to Shareholders of Cellectis: Consolidated net loss attributable to shareholders of Cellectis was $17.8 million (or a $0.18 loss per share) for the three-month period ended March 31, 2026, compared to a $18.1 million net loss (or a $0.18 loss per share) for the three-month period ended March 31, 2025. The $0.4 million decrease in net loss was primarily driven by (i) a $11.4 million improvement in net financial result, from a net financial loss of $3.9 million as of March 31, 2025 to a net financial gain of $7.4 million as of March 31, 2026, partly offset by (ii) a $11.0 million increase in operating loss. Adjusted Net Income (Loss) Attributable to Shareholders of Cellectis: Consolidated adjusted net loss attributable to shareholders of Cellectis was $16.1 million (or a $0.16 loss per share) for the three-month period ended March 31, 2026, compared to a net loss of $17.2 million (or a $0.17 loss per share) for the three-month period ended March 31, 2025. The interim condensed consolidated financial statements of Cellectis have been prepared in accordance with IAS 34 Interim Financial Reporting, and should be read in conjunction with the Group's last annual consolidated financial statements as at and for the year ended December 31, 2025. 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. 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. About Cellectis Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. The company 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 develop gene therapies in other therapeutic indications. With its in-house manufacturing capabilities, Cellectis is one of the few end-to-end gene editing companies that controls the cell and gene therapy value chain from start to finish. Cellectis’ headquarters are in Paris, France, with locations in New York and Raleigh, NC. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). To find out more, visit www.cellectis.com and follow. Cellectis on LinkedIn and X. Cautionary Statement 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 “anticipated,” “anticipates,” “believe,” “can,” “could,” “expected,” “expects,” “potential,” “potentially,” or “will” or the negative of these and similar expressions. These forward-looking statements 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 the potential of the pivotal Phase 2 BALLI-01 trial and pivotal Phase 2 ALPHA3 trial to be registrational phases, the 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 (including without limitation, the date of BLA submission), the sufficiency of cash to fund operations, the potential benefit of our product candidates and technologies, the outcomes of our collaboration agreements, including with AstraZeneca, Servier, Allogene, and Iovance, the outcomes of the dispute with Life Technologies Corporation (“LTC”) and the arbitration initiated by LTC against us, and the financial position of Cellectis. These forward-looking statements are made in light of information currently available to us and are subject to significant risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. Among these are significant risks that the BALLI-01 Phase 1 data, as well as the pivotal ALPHA 3 trial interim data may not be validated by data from later stage of clinical trials and that our product candidate may not receive regulatory approval for commercialization. Particular caution should be exercised when interpreting results from Phase 1 studies and results and interim data relating to a small number of patients – such results should not be viewed as predictive of future results. 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 as amended and in our annual financial report (including the management report) for the year ended December 31, 2025 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, which are available on the SEC’s website at www.sec.gov, 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 on Cellectis, please contact: Media contacts: Pascalyne Wilson, Director, Communications, + 33 (0)7 76 99 14 33, [email protected] Patricia Sosa Navarro, Chief of Staff to the CEO, +33 (0)7 76 77 46 93 Investor Relations contact: Arthur Stril, Chief Financial Officer & Chief Business Officer, [email protected] Attachment Earnings_Q1_2026_PR_English

This article first appeared on GuruFocus. Cash Equivalents and Fixed Term Deposits: $211 million as of December 31, 2025, compared to $264 million as of December 31, 2024. Revenue: $36.9 million cashed in from revenue in 2025. Interest Received: $8.4 million from financial and cash equivalent investments. Cash Payments: $50.5 million to suppliers, $40 million for wages, bonuses, and social expenses, $11 million for leased debts, and $5.4 million for PGE loan repayment. Overall Response Rate for Lasm Cell: 83% at the recommended phase 2 dose. CR/CRI Rate for Lasm Cell: 42% at the recommended phase 2 dose. Overall Response Rate for Eisel: 88% in phase one interim results. Complete Response Rate for Eisel: 63% in phase one interim results. Warning! GuruFocus has detected 4 Warning Signs with CLLS. Is CLLS fairly valued? Test your thesis with our free DCF calculator. Release Date: March 20, 2026 For the complete transcript of the earnings call, please refer to the full earnings call transcript. Cellectis SA (NASDAQ:CLLS) achieved a 100% overall response rate in the target Phase 2 population for its allogenic CAR T candidate, Lasm cell, in relapsed or refractory B cell acute lymphoblastic leukemia. The company has initiated a pivotal Phase 2 trial for Lasm cell, with site openings in North America and Europe, and expects the first interim analysis in Q4 2026. Cellectis SA (NASDAQ:CLLS) reported encouraging Phase 1 interim results for its dual CAR T candidate, Eisel, with an 88% overall response rate and a 63% complete response rate in non-Hodgkin's lymphoma patients. The company has strong partnerships with Allogene and Iovance, with upcoming data readouts expected to further validate its gene editing platform. Cellectis SA (NASDAQ:CLLS) has managed its cash effectively, ensuring sufficient funds to support its pivotal trials into H2 2027. The biotechnology sector has faced significant challenges, with many programs shelved and companies retreating, impacting the overall market environment. Cellectis SA (NASDAQ:CLLS) faces competition from other companies moving away from CD52 preconditioning, which could impact its clinical strategies. The company is still in the early stages of its pivotal trials, with a BLA submission for Lasm cell not expected until the second half of 2028. There are uncertainties regarding the arbitration ruling with Allogene, which could affect future licensing and milestone payments. The transition of Cellectis SA (NASDAQ:CLLS)'s therapies to outpatient settings is not yet feasible, limiting potential market expansion. Q: How is the recruitment tracking in the pivotal study for Lasm cell, and when do you expect to complete enrollment for the dose selection portion? A: Adrian Kilcoyne, Chief Medical Officer, stated that recruitment is progressing well, with site openings on track. The first interim analysis of 40 patients is expected by the end of the year, focusing on dose optimization for aletuzumab. Q: Could you provide more details on the arbitration ruling regarding the direct licensing of 501 and its impact on eligibility for the $340 million in milestones? A: Arthur Stril, Chief Financial Officer, explained that the arbitral decision returned the product Yukar T19v1 (Allo 501) to Cellectis, allowing them to develop it independently. The ruling does not affect eligibility for milestones related to AO 501a or semerce, ensuring continued eligibility for up to $340 million in development and sales milestones. Q: Can you provide insights into the decision to include CD52 preconditioning in both studies, considering some competitors are moving away from it? A: Adrian Kilcoyne emphasized the importance of aletuzumab in optimizing lympho depletion, which correlates with better patient responses. Cellectis uses a lower dose compared to others, balancing efficacy and safety, and believes this approach is optimal despite some competitors moving away from CD52. Q: How should we think about the update for Eisel in the fourth quarter, particularly regarding the breadth of update and number of patients? A: Adrian Kilcoyne mentioned that by the end of the year, data will include cohorts with and without IL-2. The focus is on enhancing the already strong complete remission rate of 63% with the addition of low-dose IL-2, aiming for further improvements in efficacy. Q: Regarding the commercial opportunity for Lasm cell, how does it compare to the launch of CD19 auto therapy in ALL? A: Adrian Kilcoyne noted that Lasm cell targets CD22, differentiating it from CD19 therapies. The market is saturated with CD19s, and Lasm cell offers an alternative for patients who relapse post-CD19 treatment. Arthur Stril added that the off-the-shelf nature of Lasm cell allows for smoother launch logistics and competitive gross margins compared to autologous therapies. For the complete transcript of the earnings call, please refer to the full earnings call transcript.

Pivotal Phase 2 with lasme-cel in r/r B-ALL (BALLI-01 trial) ongoing Phase 1: 83% ORR at RP2D and 100% ORR in the target Phase 2 population In target Phase 2 population: 100% of patients became eligible to transplant Pivotal Phase 2 first interim analysis expected in Q4 2026 BLA submission anticipated in 2028 Phase 1 with eti-cel in r/r NHL (NATHALI-01 trial) ongoing Best-in-class dual allogeneic CAR-T cell product targeting CD20 & CD22 At current dose level, 88% ORR; 63% CR rate after 2+ prior lines of therapy 93% of subjects had prior CD19 CAR-T Low-dose IL-2 cohort to be included in; Full Phase 1 dataset expected in Q4 2026 Partnerships Servier (through Allogene): Pivotal randomized Phase 2 ALPHA3 trial with cema-cel in 1L consolidation in LBCL: interim futility analysis evaluating MRD clearance and early safety results planned for April 2026 AstraZeneca: Activities progressing under the Joint Research and Collaboration Agreement Cash, cash equivalents and fixed-term deposits of $211 million as of December 31, 20251 provides runway into H2 2027 Conference call scheduled on March 20, 2026 at 8:00 am ET / 1:00 pm CET NEW YORK, March 19, 2026 (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 financial results for the fourth quarter and full year 2025, ending December 31, 2025 and provided a business update. “Lasme-cel demonstrated a potentially transformative efficacy profile in one of oncology’s most challenging settings, achieving 100% overall response rate in the target Phase 2 population. Critically, lasme-cel converted all patients in the target population into transplant-eligible candidates. The pivotal Phase 2 is now enrolling, and with a BLA submission anticipated in 2028, lasme-cel is on a clear regulatory path to potentially becoming the first off-the-shelf CAR-T therapy to address this high unmet medical need” said André Choulika, Ph.D., Co-Founder and Chief Executive Officer of Cellectis. “With interim Phase 2 data for lasme-cel in r/r B-ALL, and full Phase 1 data for eti-cel in r/r NHL, both expected in Q4 2026, we are entering an important year for Cellectis, as we advance our ambition to bring life-saving off-the-shelf CAR-T therapies to patients who have run out of options”. ________________________________ 1 Cash, cash equivalents and fixed-term deposits include restricted cash of $4.4 million as of December 31, 2025 classified as current and non-current financial assets and fixed-term deposits of $144.8 million as of December 31, 2025, classified as current financial assets. Allogeneic CAR-T Pipeline Lasme-cel in relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL) - BALLI-01 In October 2025, Cellectis presented full Phase 1 lasme-cel clinical data at the Cellectis’ R&D Day. The presented data position lasme-cel as a potentially game-changing therapy for patients with r/r B-ALL. Data highlighted: Strong efficacy: 68% overall response rate (ORR) with lasme-cel Process 2, manufactured internally (n=22) 83% ORR at the recommended Phase 2 dose (RP2D) (n=12) 100% ORR in the target Phase 2 population (n=9) In the target Phase 2 population, the complete response or complete remission with incomplete hematology recovery (CR/Cri) rate was 56%, with approximately 80% of these patients achieving minimum residual disease (MRD)-negative status Favorable safety profile: Low rates of ≥ grade 3 cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) at 2.5% and 5% respectively Transplant eligibility in target Phase 2 population: All patients became eligible for transplant Strong survival benefit: 14.8 months median overall survival (OS) in patients who achieved MRD-negative CR/CRi The first interim analysis for the pivotal Phase 2 of the BALLI-01 trial is expected in Q4 2026 (n=40). Cellectis anticipates submitting a Biologics License Application (BLA) in 2028. Eti-cel in relapsed or refractory non-Hodgkin lymphoma (r/r NHL) – NATHALI-01 In December 2025, Cellectis presented encouraging Phase 1 preliminary data of eti-cel at the American Society of Hematology (ASH) annual meeting. The data showcased the potential of eti-cel in r/r NHL patients who have relapsed following multiple lines of therapy including, for 93% of patients, an autologous CD19 CAR-T, with an 88% ORR and 63% CR at the current dose level (n=8). Cellectis is initiating patient enrollment in the cohort with low dose interleukin-2 (IL-2) support to evaluate the potential to further enhance the already high response rates and durability of response in patients with r/r NHL. Cellectis expects to present the full Phase 1 dataset in 2026, including results from the IL-2 combination. Circular single-stranded DNA (cssDNA) as a non-viral template for gene therapy In November 2025, Cellectis published a Nature Communications article establishing cssDNA as a highly efficient non-viral DNA donor template, for gene insertion in hematopoietic stem and progenitor cells (HSPCs). While viral vectors such as AAV6 are commonly used for gene insertion, they raise safety and efficacy concerns. Over the past decade, non-viral DNA templates delivery has emerged as promising alternatives. Cellectis’ research results mark a pivotal advance toward next-generation non-viral cell and gene therapies. Key findings: Superior efficiency: cssDNA achieved over 40% knock-in efficiency, outperforming linear DNA by 3-5 times. Versatility: the process successfully targets multiple loci in HSPCs and primary T cells. Better persistence: in murine models, cssDNA-edited cells showed superior engraftment and edit maintenance compared to AAV6-edited cells. TALE base editors (TALEB) safety and precision At ESGCT 2025, Cellectis presented a comprehensive safety study on TALE base editors (TALEB), which enable precise C-to-T DNA editing without causing double-strand breaks. Key study highlights: Safety assessment: researchers used advanced bioinformatics and experimental models to track potential off-target effects in the nuclear genome of primary T cells. No bias detected: the study found no evidence of unintended editing at CTCF binding sites, which are critical for genome organization and gene expression. These research results provide a strong framework for the safe development of TALEB in therapeutic cell engineering, supporting their potential for future nuclear and mitochondrial applications. Partnerships AstraZeneca – Joint Research and Collaboration Agreement Activities are progressing under the Joint Research and Collaboration Agreement with AstraZeneca, which leverages Cellectis’ gene editing expertise and manufacturing capabilities to develop up to 10 novel cell and gene therapy products for areas of high unmet medical need, including oncology, immunology and rare genetic disorders. Servier (through its sublicensee Allogene) – Anti-CD19 CAR-T Under the Servier Agreement, Cellectis is eligible to up to $340 million in development and sales milestones as well as low double-digit royalties on sales. In December 2025, an arbitral tribunal has issued its decision in the arbitration proceedings against Les Laboratoires Servier and Institut de Recherches Internationales Servier IRIS SARL (“Servier”), relating to the License, Development and Commercialization Agreement entered into between Servier and Cellectis on March 6, 2019, as amended (the “Servier Agreement”). The Tribunal ruled on a partial termination of the License Agreement with respect to product UCART19 V1 (also referred to as “ALLO-501” by Allogene) and provided that Cellectis shall, at Allogene’s request, engage in good-faith discussions regarding the granting of a direct license to product UCART19 V1. All other claims brought by the parties were dismissed. Allogene – Anti-CD70 CAR-T According to Allogene, the TRAVERSE trial in renal cell carcinoma has completed enrollment in its Phase 1b cohort, and Allogene is currently exploring partnering opportunities to advance the asset. Iovance According to Iovance, new data across several pipeline programs is anticipated throughout 2026, including a Phase 1/2 trial investigating IOV-4001, a PD-1 inactivated TIL therapy, in previously treated advanced melanoma and NSCLC. Corporate Annual Shareholders Meeting On June 26, 2025, Cellectis held a Shareholders General Meeting. At the meeting, during which approximately 57% of voting rights were exercised, resolutions 1 through 23 and resolutions 25 and 26 were adopted, while resolution 24 was rejected, consistent with the recommendations of the Board of Directors. The detailed results of the vote and the resolutions are available on Cellectis’ website: https://www.cellectis.com/en/investors/general-meetings/ Board composition The Cellectis Shareholders' Meeting appointed Mr. André Muller as a director of the Company's Board of Directors. At the close of this meeting, the term of Mr. Axel-Sven Malkomes expired, and the previously announced resignation of Mr. Pierre Bastid became effective. In connection with these changes to the Board of Directors, the Board of Directors appointed Mr. André Muller, Dr. Donald Bergstrom, and Dr. Rainer Boehm as the members of the Company’s Audit Committee. 2025 Financial Results Cash: As of December 31, 2025, Cellectis had $211 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current-financial assets. The Company believes its cash, cash equivalents, and fixed-term deposits will be sufficient to fund its operations into H2 2027. This compares to $264 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current-financial assets as of December 31, 2024. This $53 million change includes $36.9 million of cash-in from our revenue, $8.4 million of interest received from our financial and cash-equivalent investments, $2.2 million cash-in from R&D tax credit, $3.2 million cash-in from VAT credit payments, and a $4.8 million foreign currency translation impact offset by cash payments from Cellectis to suppliers of $50.5 million, Cellectis’ wages, bonuses and social expenses paid of $40.0 million, the payments of lease debts of $10.8 million, the repayment of the Prêt Garanti par l’Etat (PGE) loan for $5.4 million and the payments of capital expenditures for $3.5 million. We currently foresee focusing our cash spending at Cellectis in supporting the development of our pipeline of product candidates, including the manufacturing and clinical development expenses of lasme-cel, eti-cel and potential new product candidates, and operating our state-of-the-art manufacturing capabilities in Paris (France) and Raleigh (North Carolina). Revenues and Other Income: Consolidated revenues and other income were $79.6 million for the year ended December 31, 2025 compared to $49.2 million for the year ended December 31, 2024. This $30.4 million increase between the years ended December 31, 2024 and 2025 is mainly driven by the evolution of activities performed in connection with the research plans and fulfillment of our performance obligations under the Joint Research and Collaboration Agreement signed with AstraZeneca. Revenues as recorded in the year ended December 31, 2024 included a $5.4 million development milestone under the License Agreement signed with Servier. R&D Expenses: Consolidated R&D expenses were $93.5 million for the year ended December 31, 2025, compared to $90.5 million for the year ended December 31, 2024. This $3.0 million increase is mainly due to (i) a $4.2 million increase in personnel expenses driven by an evolution of our R&D headcount consistent with our roadmap, higher fair market value of stock-based compensation instruments due to underlying stock dynamics, and foreign exchange effects; (ii) a $0.3 million increase in depreciation and amortization; compensated by (iii) a $1.5 million decrease in purchases and external expenses. SG&A Expenses: Consolidated SG&A expenses were $19.8 million for the year ended December 31, 2025 compared to $19.1 million for the year ended December 31, 2024. The $0.7 million change is mainly due to a $0.6 million increase in purchases and external expenses. Other operating income and expenses: Other operating income and expenses decreased slightly by $0.2 million between the years ended December 31, 2024 and 2025, from $0.8 million in 2024 to $0.6 million in 2025. Net financial gain (loss): Net financial loss was $34.9 million for the year ended December 31, 2025, compared to a $22.8 million net financial gain for the year ended December 31, 2024. This $57.7 million difference reflects mainly a $28.3 million decrease in financial income and a $29.5 million increase in financial expenses between the years ended December 31, 2024 and 2025. The decrease in financial income is mainly attributable to (i) a $14.3 million gain in change in fair value of the derivative instrument component of the SIA, which was recorded last year before derecognition of the derivative in May 2024; (ii) a $7.2 million decrease in foreign exchange gains; (iii) a $1.8 million decrease in income from cash, cash equivalents and financial assets in line with the evolution of interest rates in 2025, (iv) a $ 5.7 million gain recognized in the year ended December 31, 2024 on the fair value measurement of the Tranches A, B and C warrants issued to the European Investment Bank ("EIB"), partially offset by (v) a $0.8 million increase in FX derivatives fair value gains. The increase in financial expenses is mainly attributable to a (i) $22.2 million increase in foreign exchange loss over the period due to the devaluation of the USD against the Euro, (ii) a $14.7 million loss on the fair value measurement of the Tranches A, B and C warrants issued to the EIB, (iii) a $0.7 million increase in interest on our financial and lease liabilities, partially offset by (iv) a $7.8 million decrease in the loss on fair value measurement of our investment in shares of Cibus which was entirely sold in Q1 2025. Net Income (loss) Attributable to Shareholders of Cellectis: Consolidated net loss attributable to shareholders of Cellectis was $67.6 million (or a $0.67 loss per share) for the year ended December 31, 2025, compared to a $36.8 million loss (or a $0.41 loss per share) for the year ended December 31, 2024. The $30.8 million change in net loss was primarily driven by (i) a $30.4 million increase in revenues and other income, offset by (ii) a $3.9 million increase in operating expenses and other operating income and (iii) a $57.7 million change from a net financial gain of $22.8 million as of December 31, 2024 to a net financial loss of $34.9 million as of December 31, 2025. Adjusted Net Income (Loss) Attributable to Shareholders of Cellectis: Consolidated adjusted net loss attributable to shareholders of Cellectis was $61.5 million (or a $0.61 loss per share) for the year ended December 31, 2025, compared to a net loss of $33.6 million (or a $0.37 loss per share) for the year ended December 31, 2024. The year-end consolidated financial statements of Cellectis have been prepared in accordance with International Financial Reporting Standards, as issued by the International Accounting Standards Board (“IFRS”). 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. 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® Accounting Standards. 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 Accounting Standards. 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. About Cellectis Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. The company 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 develop gene therapies in other therapeutic indications. With its in-house manufacturing capabilities, Cellectis is one of the few end-to-end gene editing companies that controls the cell and gene therapy value chain from start to finish. Cellectis’ headquarters are in Paris, France, with locations in New York and Raleigh, NC. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). To find out more, visit www.cellectis.com and follow Cellectis on LinkedIn and X. Cautionary Statement 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 ”ambition,” “anticipates,” “anticipated,” “believe,” “can,” “expected,” “expects,” “foresee,” “planned,” “potential,” “potentially,” or “will” or the negative of these and similar expressions. These forward-looking statements 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 the potential of the pivotal Phase 2 BALLI-01 trial to be a registrational phase, the 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 (including without limitation, the date of BLA submission), the sufficiency of cash to fund operations, the potential benefit of our product candidates and technologies, the outcomes of our collaboration agreement, including with AstraZeneca, Servier, Allogene, and Iovance, and the financial position of Cellectis. These forward-looking statements are made in light of information currently available to us and are subject to significant risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. Among these are significant risks that the BALLI-01 Phase 1 data may not be validated by data from later stage of clinical trials and that our product candidate may not receive regulatory approval for commercialization. Particular caution should be exercised when interpreting results from Phase 1 studies and results relating to a small number of patients – such results should not be viewed as predictive of future results. 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 as amended and in our annual financial report (including the management report) for the year ended December 31, 2025 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, which are available on the SEC’s website at www.sec.gov, 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 on Cellectis, please contact: Media contacts: Pascalyne Wilson, Director, Communications, + 33 (0)7 76 99 14 33, [email protected] Patricia Sosa Navarro, Chief of Staff to the CEO, +33 (0)7 76 77 46 93 Investor Relations contact: Arthur Stril, Chief Financial Officer & Chief Business Officer, [email protected] Attachment Earnings_Q4_2025_PR_English

Presented data underscore the potential of lasme-cel (UCART22) and eti-cel (UCART20x22) to improve outcomes in r/r B-ALL and r/r NHL: Lasme-cel in r/r B-ALL (BALLI-01) ORR of 68% with lasme-cel Process 2 (n=22), 83% at RP2D (n=12) and 100% in the target Phase 2 population (n=9) Median OS of 14.8 months in patients who achieved MRD-negative CR/CRi First interim analysis for the BALLI-01 trial expected in Q4 2026 Eti-cel in r/r NHL (NATHALI-01) ORR of 86% and 57% CR rate (n=7) Development update to be presented at the ASH 2025 annual meeting Full Phase 1 dataset expected to be shared in 2026 Servier arbitration: arbitral decision expected to be rendered on or before December 15, 2025 Cash, cash equivalents and fixed-term deposits of $225 million as of September 30, 20251 provides runway into H2 2027 NEW YORK, Nov. 07, 2025 (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 financial results for the third quarter 2025 ending September 30, 2025 and business updates. “We are proud of the promising data from our core clinical product candidates. Our lasme-cel program for r/r B-ALL and eti-cel program for r/r NHL demonstrated their ability to induce deep and meaningful responses, underscoring their potential to improve outcomes in diseases with high unmet medical needs” said André Choulika, Ph.D., Chief Executive Officer at Cellectis. “We look forward to sharing an additional development update on eti-cel at the ASH 2025 Annual Meeting and to provide the first interim analysis for the pivotal Phase 2 BALLI-01 trial in Q4 2026. Together, these milestones strengthen our leadership in allogeneic CAR-T innovation and position Cellectis for a transformative year ahead." _______________ 1 Cash, cash equivalents and fixed-term deposits include restricted cash of $4.4 million as of September 30, 2025 and fixed-term deposits of $168.2 million as of September 30, 2025, of which $137.6 million are classified as current financial assets and $30.6 million are classified as non-current financial assets (due to a fixed bank deposit investment maturing in October 2026, including accrued interest). Pipeline Highlights UCART Clinical Programs BALLI-01 study evaluating lasme-cel (UCART22) Clinical data from the Phase 1 BALLI-01 study with lasme-cel for the treatment of relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL), were presented at the Cellectis’ R&D Day that took place on October 16, 2025. The presented data position lasme-cel as a potentially game-changing therapy for patients with r/r B-ALL. In the Phase 1 of BALLI-01 study, 40 transplant ineligible third line or beyond (3L+) patients were dosed with lasme-cel: 18 patients (n=18) were dosed with product manufactured by an external CDMO (Process 1, or P1) and 22 patients (n=22) were dosed with Cellectis-manufactured product (Process 2, or P2). Highlights include: Efficacy: lasme-cel demonstrated an overall response rate (ORR) of 68% with Process 2 product (n=22), and an ORR of 83% at the recommended Phase 2 dose (RP2D; n=12) and 100% in the target Phase 2 population (n=9) Safety: in Phase 1 (n=40), lasme-cel was generally well tolerated; there was one case of grade 2 immune effector cell–associated hemophagocytic syndrome (IEC-HS), which resolved. Durability: among patients who achieved minimal residual disease (MRD)-negative complete remission or complete remission with incomplete hematologic recovery (CR/CRi), median overall survival was 14.8 months. Depth of response in target Phase 2 population: the CR/CRi rate was 56%, with approximately 80% of these patients achieving MRD-negative status. Transplant eligibility in target Phase 2 population: all patients (100%) became eligible for transplant, and 78% proceeded to transplantation. The survival curve for this study suggests a clear benefit: patients who proceeded to hematopoietic stem cell transplantation (HSCT) after lasme-cel therapy showed a trend to longer overall survival than those who did not undergo transplant. The Phase 1 data showed that lasme-cel maintained its efficacy regardless of the number or type of prior lines of treatments, including CAR-T (60% of subjects), transplant (50% of patients), and blinatumomab (80% of subjects). Following successful End-of-Phase 1 meetings with the U.S Food and Drug Administration (FDA) and the European Medicines Agency (EMA), Cellectis provided a registration path for lasme-cel in r/r ALL. The first interim analysis for the Phase 2 of the BALLI-01 trial is expected in Q4 2026. Cellectis anticipates submitting a Biologics License Application (BLA) in 2028. Commercial Opportunity for Lasme-cel As part of the R&D Day presentation, the Company discussed the potential commercial opportunity for lasme-cel in r/r B-ALL. If approved for commercialization, Cellectis estimates that lasme-cel could achieve up to approximately $700 million in potential peak gross sales across the U.S., EU4 (France, Germany, Italy, Spain) and UK in 2035, corresponding to an estimation of about 1,100 patients treated annually. Furthermore, gross peak sales could increase to up to approximately $1.3 billion with potential label expansion to second line and first line MRD+ consolidation. These estimates highlight that lasme-cel has the potential to drive meaningful growth of the CAR-T market in B-ALL, leading to a robust peak sales potential with attractive margins stemming from the allogeneic approach. American Society of Hematology (ASH) 2025 annual meeting poster presentation On November 3, 2025, Cellectis announced the acceptance of an abstract for lasme-cel for poster presentation at the American Society of Hematology (ASH) 2025 annual congress, that will take place on December 6-9, 2025. The poster highlights the correlation between alemtuzumab exposure and depth of response in the difficult-to-treat r/r ALL patients who have received lasme-cel. Additionally, the data identifies a threshold exposure level of alemtuzumab above which achieving a complete response/complete response with incomplete hematologic recovery (CR/CRi) is more likely without any increase in toxicities. The poster presentation will occur on December 8, 2025, 6:00 PM - 8:00 PM ET, in Room OCCC - West Halls B3-B4. NatHaLi-01 study evaluating eti-cel (UCART20x22) At the R&D Day, Cellectis unveiled preliminary data on eti-cel, its allogeneic CAR-T product candidate for relapsed or refractory non-Hodgkin lymphoma (r/r NHL), demonstrating an encouraging ORR of 86% and CR rate of 57% at the current dose level (n=7), with 4 out of 7 patients achieving a complete response. The preliminary high rate of complete responses underscores the potential of this innovative approach to transform outcomes for r/r NHL patients. Cellectis expects to present the full Phase 1 dataset for eti-cel, including low-dose IL-2 combination cohorts, in 2026. On November 3, 2025, Cellectis announced the acceptance of an abstract for poster presentation at ASH 2025. The poster provides a development update on eti-cel for patients with r/r NHL and outlines the addition of low dose interleukin-2 (IL-2) to further deepen and extend anti-tumor activity of eti-cel in patients with r/r NHL, supported by compelling preclinical data. The poster presentation will occur on December 7, 2025 at 6:00 PM – 8:00 PM ET, in Room OCCC – West Halls B3-B4. Innovation Circular single-stranded DNA (CssDNA) as a non-viral template for gene therapy In October 2025, Cellectis presented findings in a poster, highlighting the strong potential of circular single-stranded DNA (CssDNA) as a universal, efficient non-viral template for gene therapy, at the European Society of Gene and Cell Therapy (ESGCT) annual congress. Over the past decade, non-viral DNA template delivery has been used with engineered nucleases to target single-stranded DNA sequences in hematopoietic stem and progenitor cells (HSPCs). While developed for gene therapy purposes, so far this method has been restricted to gene corrections. To expand this scope, Cellectis developed an editing process using its gene editing technology and kilobase-long circular single-stranded DNA donor templates. The data presented show that: CssDNA editing process achieved high gene insertion frequency in viable HSPCs. CssDNA-edited HSPCs show a higher propensity to engraft and maintain gene edits in a murine model than adeno-associated viruses (AAV)-edited HSPCs. TALE base editors (TALEB) off-targets in the nuclear genome At ESGCT 2025, the Company presented in a poster a comprehensive study of TALE base editors (TALEB) off-targets in the nuclear genome. TALE base editors (TALEB) are fusions of a transcription activator-like effector domain (TALE), split-DddA deaminase halves, and an uracil glycosylase inhibitor (UGI). These recent additions to the genome editing toolbox can directly edit double strand DNA, converting a cytosine (C) to a thymine (T) through the formation of an uracil (U) intermediate without the need of DNA break. Base editing has great potential in therapeutic applications. However, being able to avoid potential off-target effects is key toward this goal. To evaluate TALEB safety, Cellectis combined advanced bioinformatic predictions with multiple experimental approaches to investigate potential off-target effects in the nuclear genome of primary T cells. The study found no evidence of biases towards off-site C-to-T editing at sites flanked by CTCF binding sites, a key DNA-binding protein that regulates genome organization and gene expression at genome wide level. These results provide a strong framework for the safe development of TALEB in therapeutic cell engineering, supporting their potential for future nuclear and mitochondrial applications. AstraZeneca – Joint Research and Collaboration Agreement In its presentation during the Cellectis’ R&D Day held in October, AstraZeneca highlighted the significance of its strategic investment and research collaboration with Cellectis to accelerate its cell therapy and genomic medicine ambitions. The collaboration leverages Cellectis’ gene editing expertise and manufacturing capabilities to develop up to 10 novel cell and gene therapy products for areas of high unmet medical need, including oncology, immunology and rare genetic disorders. Servier arbitration With respect to the ongoing arbitration proceeding through the Centre de Médiation et d’Arbitrage de Paris, the arbitral decision is expected to be rendered on or before December 15, 2025. Iovance In November 2025, Iovance reported that clinical results for IOV-4001, a PD-1 inactivated TIL cell therapy, in previously treated advanced melanoma patients are anticipated in the first quarter of 2026. Other potential indications for IOV-4001 are also in development. Financial Results Cash, cash equivalent and fixed-term deposits: As of September 30, 2025, Cellectis had $225 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current and non-current financial assets. The Company believes its cash, cash equivalents and fixed-term deposits will be sufficient to fund its operations into H2 2027. This compares to $264 million in consolidated cash, cash equivalents, restricted cash and fixed-term deposits classified as current financial assets as of December 31, 2024, with no fixed-term deposits classified as non-current financial assets as of such date. This $39 million change includes $30.5 million of cash-in from our revenue, $7.1 million of interest received from our financial and cash-equivalent investments, $2.9 million cash-in from credit VAT, $1.5 million cash-in from other financial investments, offset by cash payments from Cellectis to suppliers of $35.5 million, Cellectis’ wages, bonuses and social expenses paid of $32.4 million, the payments of lease debts of $8.1 million, the repayment of the “PGE” loan of $4.0 million and the payments of capital expenditures for $3.0 million. We currently foresee focusing our cash spending in supporting the development of our pipeline of product candidates, including the manufacturing and clinical development expenses of lasme-cel, eti-cel and potential new product candidates, and operating our state-of-the-art manufacturing capabilities in Paris (France) and Raleigh (North Carolina). Revenues and Other Income: Consolidated revenues and other income were $67.4 million for the nine-month period ended September 30, 2025, compared to $34.1 million for the nine-month period ended September 30, 2024. This $33.3 million increase between the nine-month period ended September 30, 2024 and 2025 was mainly driven by the evolution of activities performed in connection with the Research Plans and fulfillment of our performance obligations under the AstraZeneca Joint Research and Collaboration Agreement. As a reminder, revenues as recorded in the nine-month period ended September 30, 2024 included a $5.4 million development milestone under the License Agreement with Servier. R&D Expenses: Consolidated R&D expenses were $69.1 million for the nine-month period ended September 30, 2025, compared to $69.7 million for the nine-month period ended September 30, 2024, down by $0.6 million mainly driven by a decrease in purchases & external expenses of $2.1 million, offset by an increase of $1.7 million in R&D personnel expenses of which non-cash stock-based compensation increase by $1.0 million and wages and salaries increase by $0.7 million. SG&A Expenses: Consolidated SG&A expenses were $15.0 million for the nine-month period ended September 30, 2025, compared to $14.2 million for the nine-month period ended September 30, 2024. The $0.8 million change is mainly due to a non-cash stock-based compensation increase of $0.7 million and an increase of $0.1 million in purchases and external expenses. Other operating income and expenses: Other operating income increased slightly by $0.1 million between the nine-month periods ended September 30, 2024, and 2025. Net financial gain (loss): We had a consolidated net financial loss of $25.6 million for the nine-month period ended September 30, 2025, compared to an $5.7 million net financial gain for the nine-month period ended September 30, 2024. This $31.2 million difference reflects mainly (i) a one-off $14.3 million gain in change in fair value of the derivative instrument component of the Subsequent Investment Agreement dated November 7, 2023 between us and AstraZeneca Holdings (the “SIA”), which was recognized in the nine-month period ended September 30, 2024, (ii) a $5.8 million loss in the fair value remeasurement of the warrants issued to the European Investment Bank ("EIB"), as required by our finance contract entered into with EIB in December 2022 recorded in nine months period as of September 2025 to be compared to $3.9 million fair value gain recorded in 2024, (iii) a $16.7 million increase in foreign exchange loss and a $2.0 million increase in foreign exchange gain over the period due to the USD volatility, partially offset by (iv) a $7.5 million decrease in loss on fair value of our investment in shares of Cibus, Inc., which was entirely sold in the first quarter of 2025. Net Income (loss) Attributable to Shareholders of Cellectis: Consolidated net loss attributable to shareholders of Cellectis was $41.3 million (or a $0.41 net loss per share) for the nine-month period ended September 30, 2025, compared to a $42.7 million net loss (or a $0.49 net loss per share) for the nine-month period ended September 30, 2024. The $1.4 million change in net loss was primarily driven by (i) an increase in revenues and other income of $33.3 million offset by (ii) a $0.2 million increase in operating expenses and other operating income, (iii) a $31.2 million change from a net financial gain of $5.7 million as of September 30, 2024 to a net financial loss of $25.6 million as of September 30, 2025 and (iv) a decrease in deferred tax asset income of $0.5 million. Adjusted Net Income (Loss) Attributable to Shareholders of Cellectis: Consolidated adjusted net loss attributable to shareholders of Cellectis was $37.4 million (or a $0.37 loss per share) for the nine-month period ended September 30, 2025, compared to a net loss of $40.4 million (or a $0.46 loss per share) for the nine-month period ended September 30, 2024. 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. 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 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. About Cellectis Cellectis is a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies. The company 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 develop gene therapies in other therapeutic indications. With its in-house manufacturing capabilities, Cellectis is one of the few end-to-end gene editing companies that controls the cell and gene therapy value chain from start to finish. Cellectis’ headquarters are in Paris, France, with locations in New York and Raleigh, NC. Cellectis is listed on the Nasdaq Global Market (ticker: CLLS) and on Euronext Growth (ticker: ALCLS). To find out more, visit www.cellectis.com and follow Cellectis on LinkedIn and X. Cautionary Statement 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,” “can,” “could,” “estimate,” “expectation,” “expected,” “illustrative,” “look forward,” “plan,” “potential,” “potentially, “positioned,” “projected,” “suggest,” 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, include statements regarding the market market opportunities with respect to lasme-cel (and the assumptions on which such determinations are based, including with respect to addressable populations and potential pricing), the potential of the Phase 2 BALLI-01 trial to be a registrational phase, the 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 (including without limitation, the date of BLA filing), the sufficiency of cash to fund operations, the potential benefit of our product candidates and technologies, and the financial position of Cellectis. These forward-looking statements are made in light of information currently available to us and are subject to significant risks and uncertainties, including with respect to the numerous risks associated with biopharmaceutical product candidate development. Among these are significant risks that the BALLI-01 Phase 1 data may not be validated by data from later stage of clinical trials and that our product candidate may not receive regulatory approval for commercialization. Particular caution should be exercised when interpreting results from Phase 1 studies and results relating to a small number of patients – such results should not be viewed as predictive of future results. With respect to the sufficiency of cash, cash equivalent and fixed-term deposits to fund our operations, which we refer to as our runway, we note that our operating plans, including product development plans, may change as a result of various factors. Furthermore, many other important factors, including those described in our Annual Report on Form 20-F as amended and in our annual financial report (including the management report) for the year ended December 31, 2024 and subsequent filings Cellectis makes with the Securities Exchange Commission from time to time, which are available on the SEC’s website at www.sec.gov, 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 on Cellectis, please contact: Media contacts: Pascalyne Wilson, Director, Communications, + 33 (0)7 76 99 14 33, [email protected] Patricia Sosa Navarro, Chief of Staff to the CEO, +33 (0)7 76 77 46 93 Investor Relations contact: Arthur Stril, Chief Financial Officer & Chief Business Officer, [email protected] Attachment