Cellectis to Present Clinical Data on Lasme-cel and Eti-cel at EHA 2026 Annual Congress

New York, NY - May 12, 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 announced upcoming presentations on the BALLI-01 and NATHALI-01 clinical trials, at the European Hematology Association (EHA) annual congress, on June 11-14, 2026, in Stockholm, Sweden.

Lasme-cel - Oral Presentation

The abstract reporting the full Phase 1 dataset from the BALLI-01 clinical trial evaluating lasme-cel, a CD22 directed allogeneic CAR-T, in heavily pretreated patients with relapsed or refractory CD22+ B-cell acute lymphoblastic leukemia (r/r B-ALL), has been selected for oral presentation.

These data, which will be presented by Nitin Jain, M.D., Professor of Medicine, Department of Leukemia at MD Anderson Cancer Center in Houston (TX), highlight the promising safety profile and response rates in patients who have relapsed following multiple prior targeted therapies including autologous CD19 CAR-T. They form the basis for the pivotal Phase 2 program which is currently recruiting in Europe and North America.

" We are delighted to present these important data at EHA. The patients in the BALLI-01 trial had largely exhausted treatment options and faced a very poor prognosis. The depth of response we observed offers hope for these patients and demonstrates the potential for lasme-cel to become an effective therapeutic option for those with the highest unmet need. We are pursuing our pivotal Phase 2 program and plan to share the first interim analysis later this year" said Adrian Kilcoyne, M.D., MPH, MBA, Chief Medical Officer at Cellectis.

The BALLI-01 trial is currently recruiting in Pivotal Phase 2 with interim data expected to be disclosed in Q4 2026.

Oral Presentation: Safety and efficacy of UCART22 in heavily pre-treated patients with relapsed or refractory CD22+ B-cell acute lymphoblastic leukemia (B-ALL): results of the Phase 1 BALLI-01 trial

Presenter: Nitin Jain, M.D., Professor of Medicine, Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston (TX)

Session Title: Advances in the treatment of lymphoblastic leukemia

Session Room: K1

Live Session Date and Time: Saturday, June 13 at 5:15 - 6:30pm CET

Eti-cel - Poster Presentation

The abstract from the Phase 1 NATHALI-01 study evaluating eti-cel in patients with relapsed or refractory B-cell non-Hodgkin lymphoma (r/r B-NHL) has been accepted for poster presentation. This preliminary analysis explores the relationship between alemtuzumab exposure, eti-cel cellular expansion, cytokine dynamics, and clinical outcomes, providing early mechanistic insights into the optimization of the lymphodepletion regimen for this best-in-class dual-targeting CD20/CD22 allogeneic CAR T-cell product.

The Phase 1 clinical data of the NATHALI-01 clinical trial are planned to be disclosed 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

Presenter: Professor Emmanuel Bachy, M.D., Ph.D., Department of Clinical Hematology, Lyon Sud Hospital, Lyon, France.

Session: Poster Session 2

Poster Number: 4758

Session Date and Time: Saturday, June 13 at 6:45 - 7:45pm CET

The abstracts are published on the EHA website. The presentations will be available on Cellectis' website on June 11, 2026, at 8 am CET.