Cellectis

AGM Information • Dec 16, 2016

PRESS RELEASE

Cellectis Announces Conference Call To Discuss Recent Recombinant DNA Advisory Committee (RAC) Meeting

December 16, 2016 – 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 it will hold a conference call to discuss the National Institutes of Health Recombinant DNA Advisory Committee (RAC) meeting held on December 14, 2016.

The call will be held this Tuesday, December 20, 2016 at 8:30 am Eastern Time and can be accessed with the following dial-in information:

Participant dial in (Toll Free US & Canada): 877-407-3104 Participant international dial in: +1 201-493-6792

This conference call will be recorded and made available for replay for 14 days as follows:

Conference ID #: 13625168 Replay Dial-In (Toll Free US & Canada): 877-660-6853 Replay Dial-In (International): 201-612-7415 Expiration Date: 1/3/17

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 16 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 Group.

For further information, please contact:

Media contacts:

Jennifer Moore, VP of Communications, 917-580-1088, media@cellectis.com Caitlin Kasunich, KCSA Strategic Communications, 212-896-1241, ckasunich@kcsa.com

IR contact:

Simon Harnest, VP of Corporate Strategy and Finance, 646-385-9008, simon.harnest@cellectis.com

Disclaimer

This press release and the information contained herein do not constitute an offer to sell or subscribe, or a solicitation of an offer to buy or subscribe, for shares in Cellectis in any country. This press release contains forward-looking statements that relate to the Company's objectives based on the current expectations and assumptions of the Company's management only and involve risk and uncertainties that could cause the Company to fail to achieve the objectives expressed by the forward-looking statements above.

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