RESEARCH TRIANGLE PARK, North Carolina – Precision BioSciences, Inc., today announced that the United States District Court for the Eastern District of North Carolina has granted Precision’s request to stay patent infringement litigation brought against Precision by Cellectis, SA (Alternext: ALCLS). The Court has ordered that all proceedings be suspended pending final resolution and appeal of the U.S. Patent and Trademark Office (PTO) reexaminations of U.S. Patent Nos. 6,610,545 and 7,309,605. Previously, Precision announced that the PTO had issued non-final Actions Closing Prosecution in the

reexamination proceedings for both patents in which the PTO, for the second time, rejected all

claims asserted against Precision in the litigation.

Significantly, in its ruling on Precision’s motion to stay, the Court noted that it is “highly unlikely that any appeal of the PTO’s decision will be resolved prior to the expiration of the patents.” Precision expects the stay to remain in force until after the patents expire, at which point no injunction against Precision’s activities may issue under the asserted claims, and Precision will enjoy continuing freedom to operate its business. Moreover, nearly every claim asserted against Precision has been amended by the patent holders in the reexamination proceedings in an effort to overcome the PTO’s repeated rejection of the claims. To the extent any claims survive reexamination at all, Cellectis would be unable to obtain past damages for alleged infringement where, as Precision contends, those amendments are substantial in nature.

“We are thrilled that the Court has ruled in our favor and has agreed to stay this litigation,” said Jeff Smith, CSO of Precision, “We look forward to continuing to develop and commercialize Precision’s industry-leading DNE technology which enables us to efficiently target and modify chromosomal DNA inside living cells.”

“While we adamantly deny any infringement of the asserted patents, valid or otherwise, we are

pleased that the litigation has been suspended,” stated Derek Jantz, VP of Scientific

Development at Precision. “Without the burden of this oppressive and unfair legal action, we are

free to build and defend our own IP portfolio aggressively.”

“This is a key turning point in the history of our company,” said Matthew Kane, CEO of

Precision, “We look forward to competing on the merits of our technology rather than the

acumen of our attorneys.”

Precision has been represented in the patent litigation and reexamination proceedings by

WilmerHale.

About Precision BioSciences

Precision’s mission is to utilize its engineered endonuclease technology to become the world

leader in the field of genomic molecular biology. Precision’s proprietary Directed Nuclease

EditorTM (DNE) technology enables the production of custom genome editing enzymes that can

insert, remove, modify, and regulate essentially any gene in mammalian or plant cells.

Precision BioSciences has already produced hundreds of custom endonucleases for partners and

internal development that can precisely alter naturally occurring sequences within genomes.

Precision has successfully partnered its DNE technology with several of the world’s largest

agbiotech firms and is internally developing applications in biological production and human

therapeutics. For additional information, please visit www.precisionbiosciences.com.