Cellectis Announces Two Poster Presentations on Novel TALEN® Editing Process for Gene Correction and Gene Insertion in HSPCs at the ASGCT Annual Meeting

New York, NY - April 8, 2024 - 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 preliminary data exploring novel TALEN® editing process in hematopoietic stem and progenitor cells (HSPCs) will be presented at the American Society of Gene and Cell Therapy (ASGCT) 27th Annual Meeting, to be held in Baltimore, Maryland, on May 7-11, 2024.

Poster presentations:

Title: Circularization of Non-Viral Single-Strand DNA Template for Gene Correction and Gene Insertion Improves Editing Outcomes in HSPCs

Presenter: Alex Boyne, Gene Editing Platform Manager at Cellectis

Session Date/Time: May 9, 2024 at 12PM ET

Session Title: Nonviral Therapeutic Gene Delivery and Synthetic/Molecular Conjugates

Presentation Room: Exhibit Hall

Final Abstract Number: 1235

Cellectis presents the development of a novel gene editing process, leveraging the TALEN® technology and non-viral DNA template delivery, enabling highly efficient gene correction and gene insertion in hematopoietic stem and progenitor cells (HSPCs).

Title: Intron Editing of HSPC Enables Lineage-Specific Expression of Therapeutics

Presenter: Julien Valton, Ph.D., Vice President Gene Therapy at Cellectis

Session Date/Time: May 8, 2024 at 12PM ET

Session Title: Gene Targeting and Gene Correction New Technologies

Presentation Room: Exhibit Hall

Final Abstract Number: 721

Gene therapy using hematopoietic and progenitor stem cells (HSPC) has the potential to provide a lifelong supply of genetically encoded therapeutics. Gene editing strategies enabling supra-endogenous expression of therapeutics often rely on constitutive promoters resulting in transgene overexpression irrespective of cellular differentiation, which could be detrimental for HSPC function. Cellectis presents the development of a TALEN® mediated promoter-less intron editing strategy that relies on the endogenous cellular RNA splicing machinery to induce lineage-specific transgene expression exclusively after HSPC differentiation.

Full abstracts and presentations will be available on Cellectis' website following the event:

https://www.cellectis.com/en/investors/scientific-presentations/