May 10, 2017 – New York (N.Y.) –Cellectis (Alternext: ALCLS; Nasdaq: CLLS), a biopharmaceutical company focused on developing immunotherapies based on gene edited CAR T-cells (UCART), today announced that U.S. patent 8,921,332, which claims the use of chimeric restriction endonucleases for directing chromosomal gene editing in cells by homologous recombination (HR), initially issued on Dec. 30, 2014, has been upheld by the United States Patent and Trademark Office (USPTO) after a reexamination initiated in October 2015.U.S. patent 8,921,332 claims a general method for modifying chromosomal DNA sequences at a genomic site of interest within a cell by using a chimeric restriction endonuclease such as zing finger nucleases, TAL-effector nucleases, Mega-TALs and CRISPR/Cas9. This technique, commonly referred to as gene targeting or targeted insertion, is now frequently used to modify the genome within plants, animals and cell lines.The inventors of this patent are Dr. André Choulika, Cellectis’ Chairman and CEO, and Dr. Richard C. Mulligan, a Harvard Medical School Professor. Institut Pasteur and Boston Children’s Hospital, the owners of the patent, have granted exclusive rights to Cellectis under this patent. It belongs to a patent family that claims the basic uses of chimeric restriction nucleases for gene editing in cells.Following the patent’s reexamination, the USPTO issued a Notice to Issue Reexamination Certificate in which it is stated that all 55 claims of the patent are maintained, asserting that: "The '632 patent, Smith et al., the '150 patent, Kim et al. and the '261 patent individually or in combination neither teach or suggest the method of modifying a specific sequence in a chromosomal DNA of a cell in vitro by contacting the cell with a chimeric restriction endonuclease and a targeted DNA as recited in the present claims."

About Cellectis

Cellectis is a biopharmaceutical company focused on developing immunotherapies based on gene edited CAR T-cells (UCART). The company’s mission is to develop a new generation of cancer therapies based on engineered T-cells. Cellectis capitalizes on its 17 years of expertise in genome engineering - based on its flagship TALEN® products and meganucleases and pioneering electroporation PulseAgile technology - to create a new generation of immunotherapies. CAR technologies are designed to target surface antigens expressed on cells. Using its life-science-focused, pioneering genomeengineering technologies, Cellectis’ goal is to create innovative products in multiple fields and with various target markets. Cellectis is listed on the Nasdaq market (ticker: CLLS) and on the NYSE Alternext market (ticker: ALCLS). To find out more about us, visit our website: www.cellectis.com Talking about gene editing? We do it. TALEN® is a registered trademark owned by the Cellectis GroupSource: http://www.cellectis.com/en/press/cellectis-patent-encompassing-broad-uses-of-gene-editing-technologies-maintained-by-uspto/