Cellectis gets FDA RMAT status for lasme-cel in B-ALL

Rhea-AI Filing Summary

Cellectis reported that the U.S. Food and Drug Administration granted Regenerative Medicine Advanced Therapy (RMAT) designation to lasmecabtagene timgedleucel (lasme-cel), its CD22‑targeting allogeneic CAR‑T cell therapy candidate for patients with relapsed or refractory B‑cell acute lymphoblastic leukemia. The company states this designation reflects FDA recognition of lasme‑cel’s potential to address unmet medical need, based on Phase 1 BALLI‑01 data showing promising efficacy and a manageable safety profile. Final Phase 1 BALLI‑01 data will be presented in an oral session at the 2026 European Hematology Association Congress on June 13. A pivotal Phase 2 portion of the BALLI‑01 trial is open for enrollment.

Positive

• FDA RMAT designation for lasme‑cel in relapsed or refractory B‑ALL, supported by Phase 1 BALLI‑01 data showing promising efficacy and a manageable safety profile, marks a significant regulatory milestone for Cellectis’ lead allogeneic CAR‑T program.

Negative

• None.

Insights

Biotech regulatory specialist

FDA RMAT status for lasme‑cel is a meaningful regulatory milestone for Cellectis.

Cellectis reports FDA Regenerative Medicine Advanced Therapy (RMAT) designation for lasmecabtagene timgedleucel in relapsed or refractory B‑cell acute lymphoblastic leukemia. The company notes that Phase 1 BALLI‑01 data showed promising efficacy with a manageable safety profile, underpinning the designation.

Management highlights that RMAT status strengthens dialogue with FDA as lasme‑cel advances through its pivotal program. The pivotal Phase 2 portion of BALLI‑01 is open for enrollment, and final Phase 1 data will be presented on June 13, 2026 at the European Hematology Association Congress.

The company also cautions that Phase 1 findings in a small patient group may not be validated in later‑stage trials and that RMAT status can be withdrawn and may not result in faster development or review. Future clinical and regulatory updates in this program will be important for assessing lasme‑cel’s long‑term prospects.

Key Figures

Regulatory status: RMAT designation Trial phase: Phase 2 pivotal Data presentation date: June 13, 2026

3 metrics

Regulatory status RMAT designation Granted by FDA for lasme-cel in r/r B-ALL

Trial phase Phase 2 pivotal BALLI-01 pivotal phase open for enrollment

Data presentation date June 13, 2026 Final Phase 1 BALLI-01 oral presentation at EHA 2026

Key Terms

Regenerative Medicine Advanced Therapy (RMAT) designation, allogeneic CAR-T cell therapy, relapsed or refractory B-cell acute lymphoblastic leukemia, pivotal Phase 2

4 terms

Regenerative Medicine Advanced Therapy (RMAT) designation regulatory

"announced that the U.S. Food and Drug Administration (FDA) granted Regenerative Medicine Advanced Therapy (RMAT) designation"

A Regenerative Medicine Advanced Therapy (RMAT) designation is a U.S. regulatory status given to certain cell, gene, or tissue-based treatments that show promise for serious conditions and early clinical evidence of benefit. It signals that regulators will provide extra guidance and expedited review steps—like giving a promising project a “fast pass” through some development checkpoints—which can shorten time to market and reduce regulatory risk, making the program more valuable and noteworthy to investors.

allogeneic CAR-T cell therapy medical

"its CD22-targeting allogeneic CAR-T cell therapy product candidate"

A therapy in which immune cells taken from a healthy donor are genetically reprogrammed to recognize and kill cancer cells and then given to a patient; think of it as an off‑the‑shelf, engineered immune weapon rather than one made from the patient’s own tissue. It matters to investors because this approach can be faster and cheaper to manufacture at scale than patient‑specific therapies, but carries additional risks such as immune rejection, regulatory hurdles and complex manufacturing that affect clinical success, costs and commercial potential.

relapsed or refractory B-cell acute lymphoblastic leukemia medical

"for the treatment of patients with relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL)"

pivotal Phase 2 medical

"The BALLI-01 trial Pivotal Phase 2 is open for enrollment."

A pivotal phase 2 is a mid-stage clinical trial intentionally designed to provide the decisive evidence needed to judge whether a new drug or treatment works and is safe enough to advance toward regulatory approval or larger trials. Think of it as a detailed dress rehearsal: it tests the key questions investors care about — does the treatment benefit patients and have an acceptable risk — and its results can strongly influence a company’s value and next financing or development steps.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Cellectis (CLLS) announce regarding lasme-cel in this 6-K?

Cellectis announced that the FDA granted Regenerative Medicine Advanced Therapy (RMAT) designation to lasmecabtagene timgedleucel (lasme-cel) for treating relapsed or refractory B-cell acute lymphoblastic leukemia, recognizing its potential based on Phase 1 BALLI-01 efficacy and safety data.

What is lasmecabtagene timgedleucel (lasme-cel) and which patients is Cellectis targeting?

Lasmecabtagene timgedleucel, or lasme-cel, is Cellectis’ CD22-targeting allogeneic CAR-T cell therapy product candidate. It is being developed for patients with relapsed or refractory B-cell acute lymphoblastic leukemia, a group facing significant unmet medical need despite existing treatments.

What clinical data support the FDA RMAT designation for Cellectis’ lasme-cel?

The RMAT designation is supported by Phase 1 BALLI-01 trial data. Cellectis reports these data showed promising efficacy and a manageable safety profile for lasme-cel in relapsed or refractory B-cell acute lymphoblastic leukemia, encouraging further development into a pivotal Phase 2 program.

What is the status of the BALLI-01 trial for Cellectis’ lasme-cel program?

Cellectis states that the pivotal Phase 2 portion of the BALLI-01 trial evaluating lasme-cel is open for enrollment. Final Phase 1 BALLI-01 results will be presented in an oral session at the 2026 European Hematology Association Congress on June 13 in the late afternoon.

How does Cellectis describe the significance of RMAT designation for lasme-cel?

Cellectis’ CEO calls the RMAT designation a meaningful recognition of the need for off-the-shelf CAR-T options for relapsed or refractory B-ALL patients. He also notes the designation strengthens the company’s dialogue with the FDA as lasme-cel advances through its pivotal development program.

What cautions does Cellectis highlight about lasme-cel and the RMAT designation?

Cellectis cautions that Phase 1 data from a small patient group may not predict later-stage results and that lasme-cel might not receive regulatory approval. The company adds RMAT designation can be lost and may not lead to faster development, review, or approval processes.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/09/2026 - 04:35 PM Learn about SEC filing dates

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

Date of Report: June 9, 2026

Commission File Number: 001-36891

Cellectis S.A.
(Exact Name of registrant as specified in its charter)

8, rue de la Croix Jarry
75013 Paris, France
+33 1 81 69 16 00
(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.
Form 20-F [ X ]      Form 40-F [   ]

EXHIBIT INDEX

Exhibit		Title
99.1		Press Release dated June 9, 2026

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

		Cellectis S.A.
		(Registrant)
Date: June 9, 2026		/s/ André Choulika
		André Choulika
		Chief Executive Officer

EXHIBIT 99.1

Cellectis Receives FDA RMAT Designation for lasme-cel, the First Allogeneic CAR-T Therapy in a Pivotal Trial for Patients with r/r B-ALL

NEW YORK, June 09, 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 announced that the U.S. Food and Drug Administration (FDA) granted Regenerative Medicine Advanced Therapy (RMAT) designation to lasmecabtagene timgedleucel (lasme-cel), its CD22-targeting allogeneic CAR-T cell therapy product candidate, for the treatment of patients with relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL).

The granting of RMAT designation reflects the FDA's recognition of the potential for lasme-cel to address the unmet medical need faced by patients with r/r B-ALL.

The RMAT designation is supported by Phase 1 BALLI-01 data demonstrating promising efficacy and a manageable safety profile. Final Phase 1 data from the BALLI-01 trial of lasme-cel will be presented in an oral session at the 2026 Congress of the European Hematology Association (EHA) this Saturday, June 13 at 5:15 – 6:30pm CET by Nitin Jain, M.D., Professor of Medicine, Department of Leukemia at MD Anderson Cancer Center in Houston (TX).

“As the company that pioneered allogeneic CAR-T, we see the RMAT designation for lasme-cel as a meaningful recognition of the need for off-the-shelf CAR-T options for patients with relapsed or refractory B-ALL, patients who cannot wait. This designation strengthens our dialogue with the FDA as we advance lasme-cel through its pivotal program" said André Choulika, Ph.D., Co-founder and Chief Executive Officer of Cellectis.

The BALLI-01 trial Pivotal Phase 2 is open for enrollment. Information on participant eligibility and participating clinical centers can be found on clinicaltrials.gov: BALLI-01 (NCT04150497).

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 “potential,” 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. In addition, there are risks of losing the RMAT designation if it is established that the product no longer meets the criteria, and that this designation will not lead to a faster development or regulatory review or approval process. 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,
media@cellectis.com               

Investor Relations contact:           
Arthur Stril, Chief Financial Officer & Chief Business Officer, investors@cellectis.com

Attachments

• PRESS RELEASE-RMAT designation (1) (https://ml.globenewswire.com/Resource/Download/af81c16e-0339-4abc-9153-f396d71e9c70)

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 PRESS RELEASE 7.6 KB