Cema-Cel Pivotal Trial Interim Data Highlight Strength of Cellectis’ Allogeneic CAR-T Platform

New York, NY - April 13, 2026 - Cellectis (or 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 highlights the interim futility analysis announced by Allogene Therapeutics, Inc. ("Allogene") from Allogene's sponsored pivotal ALPHA3 trial evaluating cema-cel in first-line consolidation for large B-cell lymphoma (LBCL). 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 sublicenced by Servier to Allogene in certain territories.

Allogene announced the futility analysis, which was triggered by the protocol-defined data cutoff of the 24th patient completing Day 45 minimal residual disease ("MRD") assessment, showed that 58.3% (7/12) of patients in the cema-cel arm achieved MRD negativity compared to 16.7% (2/12) in the observation arm, representing a 41.6% absolute difference in MRD clearance between the arms. 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. Allogene further announced that the cema-cel treatment was generally well-tolerated as of the cutoff, with most patients (10/12) managed in the outpatient setting post-infusion, no cases of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), graft-versus-host disease (GvHD) or treatment-related Serious Adverse Events, and no hospitalizations for treatment-related Adverse Events. For more details on the data announced by Allogene, please refer to Allogene's press release click here.

"Seeing cema-cel advance in a pivotal trial is a great moment. Cema-cel derives from the first allogeneic CAR-T ever made, UCART19, as Cellectis has pioneered the concept of allogeneic "off-the-shelf" cell therapy, a concept many considered impossible. The data disclosed by Allogene is a testament to that vision, as we believe our allogeneic platform will replace autologous CAR-T therapies and expand their use in more indications. We warmly congratulate Servier and Allogene on this milestone and look forward to the continued development of cema-cel" said André Choulika, Ph.D., Co-Founder and Chief Executive Officer of Cellectis.

Cema-cel, which is derived from the UCART19 product initially developed by Cellectis, is an anti-CD19 allogeneic CAR-T cell therapy. Unlike autologous CAR-T therapies, which are manufactured from each patient's own T-cells, cema-cel is derived from healthy donor T-cells. We believe that allogeneic treatment have the potential to overcome many of the challenges of autologous cell therapies including speed, accessibility, and product consistency, while offering a path to make cell therapies mainstream pharmaceutical products.

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 Biologics License Application (BLA) submission. Under the Servier Agreement, Cellectis is eligible to receive payments up to $340 million in development and sales milestones, as well as low double-digit royalties on net sales of licensed CD19 products, including cema-cel developed in LBCL.