Paris (France): Cellectis SA (Alternext: ALCLS), the French genome engineering company, provided an update today regarding its recent patent litigations against Precision Biosciences, Inc. (“Precision”). On November 30th 2010, in the District of Delaware, Cellectis brought suit against Precision for infringement of Cellectis’s U.S. Patent No. 7,842,489. Shortly thereafter, on March 1st, 2011, Cellectis brought a second suit against Precision for infringement of Cellectis’s U.S. Patent No. 7,897,372, also filed in the District of Delaware. In a related matter to Cellectis’s suits against Precision for infringement, Precision field suit last week against Cellectis in the Eastern District of North

Carolina, alleging infringement of its U.S. Patent No. 8,021,867 (“the ‘867 patent”).

Cellectis believes that the claims of the ‘867 patent are invalid. Cellectis also believes that this patent is too narrow to cover its meganucleases and, therefore, should not interfere with Cellectis continuing its business of making, using and selling such meganucleases. Consistent with this belief and to counter the allegations made in Precision’s suit on the

‘867 patent, Cellectis also filed a new suit last week in the District of Delaware, seeking a declaration that Precision’s ‘867 patent is invalid and not infringed by Cellectis. Importantly, Cellectis will continue its robust leadership efforts in the meganuclease business and vigorously enforce its intellectual property rights, including through actions such as those above.

About Cellectis

Cellectis improves life by applying its genome engineering expertise to a broad range of applications, including human therapeutics, bioresearch and agriculture. Cellectis is listed on the NYSE-Euronext Alternext market(code: ALCLS) in Paris. More information at: www.cellectis.com.