Cellectis

Regulatory Filings • Nov 5, 2015

PRESS RELEASE

Cellectis to Present Data on its Allogeneic CAR T-Cell Immunotherapy Product Candidates during the Upcoming ASH Annual Meeting

New York, November 5, 2015 – Cellectis (Alternext: ALCLS – Nasdaq: CLLS) today announced that data on its engineered allogeneic CAR T-Cell product candidates, UCARTCS1 and UCART123, will be presented during the 2015 American Society of Hematology Annual Meeting. A poster and an oral presentation will be presented during this event.

Bypassing the Constraint for Chimeric Antigen Receptor (CAR) Development in T-Cells Expressing the Targeted Antigen: Improvement of Anti-CS1 CAR Activity in Allogenic TCRa/CS1 Double Knockout T-Cells for the Treatment of Multiple Myeloma (MM)

Oral presentation

Session Name: Myeloma: Pathophysiology and Pre-Clinical Studies, excluding Therapy: Novel Immunotherapeutics and the Impact of the Microenvironment Presentation Time: Saturday, December 5, 2015 at 2:15 PM

TCRab Deficient CAR T-Cells Targeting CD123: An Allogeneic Approach of Adoptive Immunotherapy for the Treatment of Acute Myeloid Leukemia (AML) Poster presentation

Session Name: Acute Myeloid Leukemia: Novel Therapy, excluding Transplantation: Poster II

Presentation Time: Sunday, December 6, 2015 from 6:00 PM to 8:00 PM

About Cellectis

Cellectis is a biopharmaceutical company focused on developing immunotherapies based on gene edited engineered 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 15 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 genome-engineering technologies, Cellectis' goal is to create innovative products in multiple fields and with various target markets. Cellectis S.A. is listed on the Nasdaq Global 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:

Jennifer Moore, VP Communications Phone: 917-580-1088 email: media@cellectis.com

Caitlin Kasunich / Dixon Moretz KCSA Strategic Communications Phone: 212.896.1241 / 212.896.1251 email: ckasunich@kcsa.com / dmoretz@kcsa.com

Simon Harnest, VP Finance and Investor Relations Phone: 646-385-9008 email: 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.