Cellectis Presents Research Data on a Novel Immune-Evasive Universal CAR T-cell at ASGCT

New York, NY – May 16, 2022 - 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 will present its first research data on the development of a novel universal CAR T-cell with immune-evasive properties using TALEN®-gene editing, at the American Society of Cell and Gene Therapy Annual Meeting (ASGCT) being held on May 16-19, 2022. This novel immune-evasive CAR T-cell scaffold evades NK (Natural Killer) cell and alloresponsive T-cell attacks and imparts efficient antitumor activity in vitro and in vivo.

Cellectis’ novel immune-evasive CAR T-cell (ΔTRACCARΔB2MHLAE), was developed using a combination of TALEN®-mediated gene editing and adeno-associated virus (AAV) dependent gene insertion. ΔTRACCARΔB2MHLAE is devoid of TCRαβ and human leukocyte antigen (HLA) Class I expression and endowed with an engineered surface-exposed HLA-E. These three features could enable CAR T-cells to prevent graft versus host (GvH) reaction and evade the cytolytic activities from alloresponsive T-cells and NK cells.

« Universal CAR T-cell therapies are poised to revolutionize cancer treatment and to improve patient outcomes. Realizing these advantages in an allogeneic setting requires universal CAR T cells that can kill target tumor cells, avoid depletion by the host immune system, and proliferate without attacking host tissues. Cellectis’ research suggested that ΔTRACCARΔB2MHLAE T-cells evade NK cell and alloresponsive T-cell attacks and showed prolonged antitumor activity in the presence of cytotoxic levels of NK cells. This new cellular scaffold could enable the broad use of universal CAR T-cells in allogeneic settings and holds great promise for clinical applications. » said Julien Valton, Ph.D., Vice President Gene Therapy at Cellectis.

Research data showed that:

• ΔTRACCARΔB2MHLAE overcame alloresponsive T-cell and NK cells attacks.
• The immune-evasive property of ΔTRACCARΔB2MHLAE was similar toward NK cells from healthy donors, acute myeloid leukemia (AML) patients and acute lymphocytic leukemia (ALL) patients.
• ΔTRACCARΔB2MHLAE T-cells exhibit prolonged antitumor activity in the presence of cytotoxic levels of NK cells.
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Title: Endowing Universal CAR T-cell with Immune-Evasive Properties Using TALEN® -Gene Editing
Session Date: May 16, 2022

Presentation Time: 3:45pm - 4:00pm ET

Location: Walter E. Washington Convention Center
Session title: Cell-Based Cancer Immunotherapies I
Room: 207
Final abstract number: 99

The research data will be presented today in an oral presentation. The abstract can be accessed on the ASGCT website, and the oral presentation will be posted on Cellectis’ website during the conference.