Cellectis Files First Clinical Trial Application for UCART19, an Allogeneic Gene Edited CAR T-Cell Product for Hematological Malignancies NEW YORK--(BUSINESS WIRE)

Files First Clinical Trial Application for UCART19, an Allogeneic Gene

Edited CAR T-Cell Product for Hematological Malignancies

NEW YORK--(BUSINESS WIRE)--December 23, 2015--Regulatory News:

Cellectis (Paris:ALCLS) (NASDAQ:CLLS) (Alternext: ALCLS - Nasdaq: CLLS)

today announced the submission of a clinical trial application (CTA) to

the Medicines & Healthcare products Regulatory Agency (MHRA) requesting

approval to initiate UCART19 First-in-Human clinical investigation in

leukemia in the United Kingdom.

This study aims to include CD19-positive Acute Lymphoblastic Leukemia

(ALL) patients. Other eligibility criteria to enter clinical trials will

be assessed by the investigators.

"It has been a privilege preparing this application with our team,

partners, investigators and subcontractors, in close interaction with

MHRA, rewarding many years of intense work to overcome the challenges

that are inherent to advanced therapy medicinal products. This

achievement marks an important step toward making UCART19 available to

patients," said Stephan Reynier, Chief Regulatory and Compliance

"The UCART19 CTA filing is a great recognition for the Company's

preclinical and manufacturing accomplishments in developing a

therapeutic for Acute Lymphoblastic Leukemia. We are all pleased with

Cellectis' progress to date with UCART19, including the filing of this

CTA, and we look forward to following the progress of this program

through the course of its clinical development," said Dr. Mathieu Simon,

EVP, Chief Operating Officer, Cellectis.

UCART19 is a potential best-in-class allogeneic TALEN gene edited

T-cell product for treatment of CD19 expressing hematological

malignancies, initially developed in Chronic lymphocytic leukemia (CLL)

and Acute lymphoblastic leukemia (ALL). Engineered allogeneic CD19 CAR

T-cells currently stand out as a real therapeutic innovation for

treating various types of leukemia and lymphoma. Cellectis' approach

with UCART19 is based on the preliminary positive results from clinical

trials using products based on the CAR technology and has the potential

to overcome the limitation of the autologous current approach by

providing an allogeneic frozen, "off the shelf" T-cell based medicinal

On November 18, 2015 Servier exercised its worldwide option to license

UCART19 and entered into a global development and commercialization

collaboration with Pfizer on UCART19. According to their recent

agreement, Cellectis will hand over the clinical development of UCART19

to Servier and their US partner Pfizer. Due to the early exercise,

Cellectis is no longer responsible for funding the UCART19 Phase I

Information about ongoing clinical trials are publically available on

dedicated websites such as:

www.clinicaltrials.gov in the U.S.

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.

This press release contains "forward-looking" statements that are based

on our management's beliefs and assumptions and on information currently

available to management.

Forward-looking statements involve known and unknown risks,

uncertainties and other factors that may cause our actual results,

performance or achievements to be materially different from any future

results, performance or achievements expressed or implied by the

forward-looking statements.

The risks and uncertainties include, but are not limited to the risk of

not obtaining regulatory approval to commence clinical trials on our

UCART product candidates, including UCART19, the risk that our

collaboration with Servier or our relationships with the principal

investigator will not continue or will not be successful, and the risk

that any one or more product candidates will not be successfully

developed and commercialized.

You should read the Company's Prospectus, including the Risk Factors set

forth therein and the exhibits thereto, completely and with the

understanding that our actual future results may be materially different

from what we expect. Except as required by law, we assume no obligation

to update these forward-looking statements publicly, or to update the

reasons actual results could differ materially from those anticipated in

the forward-looking statements, even if new information becomes

available in the future.

Jennifer Moore, 917-580-1088

Caitlin Kasunich, 212-896-1241

Harnest, 646-385-9008

VP Finance and Investor Relations