Cellectis Reports Financial Results for the Second Quarter 2026

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, 2026 [1] provide runway into Q4 2027.

New York, NY - August 6, 2026 - 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.

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 a t 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.

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/

[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.

[2] IEC-HS includes the preferred terms immune effector cell-associated HLH-like syndrome and Hemophagocytic lymphohistiocytosis.