Cellectis Announces Poster Presentation on TALEN®-edited MUC1 CAR T-cells Targeting Triple Negative Breast Cancer at the American Association of Cancer Research (AACR) Annual Meeting

New York, NY – March 14, 2023 – 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 preclinical data exploring purposeful armoring of CAR T-cells to enhance efficacy of MUC1 CAR T-cells in targeting triple-negative breast cancer, will be presented at the American Association of Cancer Research (AACR) Annual Meeting, to be held in Orlando, Florida on April 14-19, 2023.

“We are proud to present updated preclinical data on our product candidate UCARTMUC1 for solid tumors at AACR 2023” said Laurent Poirot, Ph.D., Senior Vice President Immunology at Cellectis. “As immune-therapies continue to develop for solid tumors, the tumor microenvironment (TME) poses many challenges that CAR T-cells need to overcome for efficient tumor cell clearance. Our preclinical data make us confident that UCART MUC1 could be a valuable product candidate for patients with highly unmet medical needs.”

Presentation includes:

Poster presentation:

Therapeutic options for triple negative breast cancer (TNBC) remain limited to date despite it being the most aggressive subtype of breast cancers and carrying the poorest prognosis. Tumor-associated MUC1 antigen is overexpressed in a large number of TNBC patients offering an effective discriminatory target for CAR T-cell therapy.

Cellectis will present innovative strategies exploring purposeful armoring of CAR T-cells to boost efficiency while preserving safety. To maintain anti-tumor CAR T-cell activity and proliferation in the hostile TME of solid tumors, Cellectis developed state-of-the-art multiplexed gene editing using high precision TALEN® technology. With that aim, we armored allogeneic CAR T-cells with specific attributes to locally release immune inflammatory cytokines and protect from inhibitory effects of the TGFB1 and PD1 pathways. A combination of strategies using allogeneic CAR T-cells with diverse attributes were evaluated against TNBC tumors in various in vivo pre-clinical models. The recirculation pattern of MUC1 CAR T-cells was also explored in relationship with their delivery routes.

Title: Deciphering the benefits of variable delivery routes and molecular armoring to enhance efficacy of MUC1-CAR T-cells in targeting triple-negative breast cancer

Session Title: Adoptive Cell Therapy 1

Presenter: Piril, Erler, Ph.D., Scientist II, Immuno-Oncology, Cellectis

Session Date and time: Sunday April 16, 2023, 1:30-5:00 PM ET
Location: Section 37
Poster Board Number: 14
Abstract Presentation Number: 899