Cellectis Presents Data on Two TALEN®-based Gene Therapy Preclinical Programs for Patients with Sickle Cell Disease and Mucopolysaccharidosis type I at ESGCT 2022

Cellectis announced that the Company will present both an oral and poster at the European Society of Gene and Cell Therapy's (ESGCT) 29thCongress, to be held in Edinburgh from October 11-14, 2022. Presentation details: Pre-clinical data presentation on a non-viral DNA delivery associated with TALEN® gene editing that leads to highly efficient correction of sickle cell mutation in long-term repopulating hematopoietic stem cells. Sickle cell disease stems from a single point mutation in the HBB gene which results in sickle hemoglobin.

Cellectis leveraged its TALEN® technology to develop a gene editing process that leads to highly efficient HBB gene correction via homology directed repair, while mitigating potential risks associated to HBB gene knock-out. Overall, these results show that non-viral DNA delivery associated with TALEN® gene editing reduces the toxicity usually observed with viral DNA delivery and allows high levels of HBB gene correction in long-term repopulating hematopoietic stem cells. The oral presentation titled “Non-viral DNA delivery associated to TALEN® gene editing leads to highly efficient correction of sickle cell mutation in long-term repopulating hematopoietic stem cells”, will be made on Thursday, October 13,2022 8:30 AM-10:45 AM BST by Arianna Moiani, Ph.D., Senior Scientist & Team Leader Innovation Gene Therapy. The presentation can be found on the Cellectis website on the day of the presentation.

Presentation details: Pre-clinical data presentation on TALEN®-mediated engineering of HSPC that enables systemic delivery of IDUA. Mucopolysaccharidosis type I (MPS-I) is caused by deficiencies in the alpha-L-iduronidase (IDUA) gene and it is associated with severe morbidity representing a significant unmet medical need. Cellectis established a TALEN®-based ex vivo gene editing protocol to insert an IDUA-expression cassette into a specific locus of HSPC. Editing rates?in vivo?were 6-9% sixteen weeks after injection, depending on the tissue analyzed (blood, spleen, bone marrow).

Lastly, 8.3% of human cells were edited in the brain compartment. Cellectis established a safe TALEN®-based gene editing protocol procuring IDUA-edited HSPCs able to engraft, differentiate into multiple lineages and reach multiple tissues, including the brain.