Cellectis Presents ‘Smart CAR T’ Strategy to Enhance Efficacy Against Solid Tumors at AACR-IO 2025

New York, NY - February 24, 2025 - 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, showcases an innovative strategy for T cell engineering that leverages the pro-inflammatory properties of interleukin 2 (IL-2) with the objective to enhance CAR T cell efficacy against solid tumors, at the American Association for Cancer Research - Immuno-oncology (AACR-IO), taking place on February 23-26, 2025 in Los Angeles, CA.

The data are presented in a poster:

CAR induced expression of synthetically engineered FAP-IL2v immunocytokine boosts persistent anti-tumor activity of TALEN-edited allogeneic CAR T-cells without associated IL-2 toxicity

Presenter: Shipra Das, Ph.D., Associate Director Immuno-Oncology, at Cellectis.

Date/Time: February 25, 2025, 1:45-4:45 p.m. PT

Session: Poster Session B

CAR T-cell therapies have transformed the treatment landscape for specific hematological malignancies and have shown promising preliminary efficacy in solid tumors.

Recent studies suggest a link between the in vivo expansion and persistence of CAR-T cells and enhanced therapeutic outcomes in patients. The co-administration of interleukin-2 (IL-2) has been demonstrated to improve CAR T-cell engraftment, expansion, and functionality in preclinical models but poses toxicity risks at high doses.

Using Cellectis' TALEN® gene editing technology, we developed 'Smart CAR T cells' with the ability to express a CAR-inducible IL-2 variant (IL-2v) immunocytokine, potentiated by tumor-specific cues for localized activity within the solid tumor microenvironment (TME).

CAR-inducible expression of this recombinant FAPscFv-IL2v boosts anti-tumor activity of engineered CAR T-cells both in vitro and in vivo. Notably, the enhancement of CAR T-cell activity mediated by IL-2v relies on its anchoring to the FAP protein, which is uniquely present in the TME, thus minimizing the systemic toxicity typically associated with circulating free IL-2 cytokines.

This proposed cellular engineering strategy would represent an effective and safe method to substantially improve CAR T cell expansion and anti-tumor activity, while confining IL-2 activity to the tumor microenvironment.

The poster is published on Cellectis' website.