Servier and Pfizer Announce FDA Clearance of IND Application for UCART19 in Adult Relapsed/Refractory Acute Lymphoblastic Leukemia

NEW YORK–(BUSINESS WIRE)– Regulatory News:

Servier, together with Pfizer Inc. (NYSE:PFE) and Cellectis
(Paris:ALCLS) (NASDAQ:CLLS) (Alternext: ALCLS; Nasdaq: CLLS), announced
today that the U.S. Food and Drug Administration (FDA) has granted
Servier with an Investigational New Drug (IND) clearance to proceed in
the U.S. with the clinical development of UCART19, an allogeneic,
gene-edited cellular therapy candidate to treat relapsed/refractory
acute lymphoblastic leukemia.

Servier is sponsoring the CALM Phase 1 study on UCART19. In 2015,
Servier acquired exclusive rights from Cellectis for UCART19, which is
being co-developed by Servier and Pfizer.

The CALM study was initiated in the UK in August 2016. CALM is an open
label, dose-escalation study designed to evaluate safety, tolerability
and antileukemic activity of UCART19 in patients with relapsed or
refractory CD19-positive B-cell acute lymphoblastic leukemia (B-ALL).

The allogeneic UCART19 candidate and CALM protocol were reviewed at the
National Institutes of Health’s Recombinant DNA Advisory Committee (RAC)
meeting on December 14, 2016. Servier submitted an IND application on
February 1, 2017, with Pfizer’s support. With this IND clearance, the
CALM study will be expanded to include several centers in the U.S.,
including the MD Anderson Cancer Center in Houston (Texas).

“We are very pleased that Servier’s first IND approval has been granted
for such an innovative approach as allogeneic CAR T therapy”, said Dr
Patrick Thérasse, Director of Clinical Development Oncology at Servier.
“B-ALL is a devastating disease and this study is key to gaining greater
insight into the efficacy and safety profile of this new immune-oncology
approach in patients with B-ALL.”

“Pfizer is excited by the potential of this investigational CAR T
approach to treating ALL and other B-Cell malignancies,” said Barbara
Sasu, Vice President, CAR T Research at Pfizer. “We are looking forward
to having the opportunity to investigate this approach in the U.S.”

About UCART19

UCART19 is an allogeneic CAR T-cell product candidate being developed
for treatment of CD19-expressing hematological malignancies, gene edited
with TALEN®. UCART19 is initially being developed in acute lymphoblastic
leukemia (ALL) and is currently in Phase I. The current approach with
UCART19 is based on the preliminary positive results from clinical
trials using autologous products based on the CAR technology. UCART19
has the potential to overcome the limitation of the current autologous
approach by providing an allogeneic, frozen, “off-the-shelf” T cell
based medicinal product.

In November 2015, Servier acquired the exclusive rights to UCART19 from
Cellectis. Following further agreements, Servier and Pfizer began
collaborating on a joint clinical development program for this cancer
immunotherapy. Pfizer has been granted exclusive rights by Servier to
develop and commercialize UCART19 in the United States, while Servier
retains exclusive rights for all other countries.

About Servier

Servier is an international pharmaceutical company governed by a
non-profit foundation with its headquarters in Suresnes (France). With a
strong international presence in 148 countries and a turnover of 4
billion euros in 2016, Servier employs 21 000 people worldwide.
Corporate growth is driven by Servier’s constant search for innovation
in five areas of excellence: cardiovascular diseases, diabetes, cancers,
immune-inflammatory diseases, and neurodegenerative diseases, as well as
by its activities in high-quality generic drugs. Being completely
independent, the Group reinvests 25% of turnover (excluding generics) in
research and development and uses all its profits for growth.

Becoming a key player in oncology is part of Servier’s long-term
strategy. Currently, there are nine molecular entities in clinical
development in this area, targeting gastric and lung cancers and other
solid tumors, as well as various leukemias and lymphomas. This portfolio
of innovative cancer treatments is being developed with partners
worldwide, and covers different cancer hallmarks and modalities,
including cytotoxics, proapoptotics, targeted, immune and cellular
therapies, to deliver life-changing medicines to patients.

More information: www.servier.com

Pfizer Inc.: Working together for a healthier world®

At Pfizer, we apply science and our global resources to bring therapies
to people that extend and significantly improve their lives. We strive
to set the standard for quality, safety and value in the discovery,
development and manufacture of healthcare products. Our global portfolio
includes medicines and vaccines, as well as many of the world’s
best-known consumer healthcare products. Every day, Pfizer colleagues
work across developed and emerging markets to advance wellness,
prevention, treatments and cures that challenge the most feared diseases
of our time. Consistent with our responsibility as one of the world’s
premier innovative biopharmaceutical companies, we collaborate with
health care providers, governments and local communities to support and
expand access to reliable, affordable health care around the world. For
more than 150 years, Pfizer has worked to make a difference for all who
rely on us. To learn more, please visit us at www.pfizer.com.
In addition, to learn more, follow us on Twitter at @Pfizer and
@Pfizer_News, LinkedIn and like us on Facebook at Facebook.com/Pfizer.

Pfizer Disclosure Notice

The information contained in this release is as of 9 March 2017.
Pfizer assumes no obligation to update forward-looking statements
contained in this release as the result of new information or future
events or developments.

This release contains forward-looking information about a product
candidate, UCART19, including its potential benefits, that involves
substantial risks and uncertainties that could cause actual results to
differ materially from those expressed or implied by such statements. Risks
and uncertainties include, among other things, the uncertainties
inherent in research and development, including the ability to meet
clinical study commencement and completion dates as well as the
possibility of unfavorable study results, including unfavorable new
clinical data and additional analyses of existing clinical data; whether
and when drug applications may be filed for UCART19 in any jurisdiction;
whether and when any such applications may be approved by regulatory
authorities, which will depend on the assessment by such regulatory
authorities of the benefit-risk profile suggested by the totality of the
efficacy and safety information submitted; decisions by regulatory
authorities regarding labeling and other matters that could affect the
availability or commercial potential of UCART19; and competitive
developments.

A further description of risks and uncertainties can be found in
Pfizer’s Annual Report on Form 10-K for the fiscal year ended December
31, 2016 and in its subsequent reports on Form 10-Q, including in the
sections thereof captioned “Risk Factors” and “Forward-Looking
Information and Factors That May Affect Future Results”, as well as in
its subsequent reports on Form 8-K, all of which are filed with the U.S.
Securities and Exchange Commission and available at www.sec.gov
and www.pfizer.com.

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 17 years of expertise
in genome engineering – based on its flagship TALEN® products and
meganucleases as well as its 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 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.

Cellectis Disclaimer

This press release contains “forward-looking” statements that are based
on our management’s current expectations 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 that
the preliminary results from our product candidates will not continue or
be repeated, the risk of not obtaining regulatory approval to commence
clinical trials on the UCART product candidates, the risk that any one
or more of our product candidates will not be successfully developed and
commercialized. Further information on the risks factors that may affect
company business and financial performance, is included in filings
Cellectis makes with the Security Exchange Commission from time to time
and its financial reports. 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.

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