Cellectis’ UCART123 Administered to First Patient with BPDCN in Phase I Clinical Trial at MD Anderson Cancer Center

UCART123 is First U.S. Gene Edited, Off-the-Shelf CAR T-Cell
Program

NEW YORK–(BUSINESS WIRE)–Regulatory News:

Cellectis
(Paris:ALCLS) (NASDAQ:CLLS) (Alternext: ALCLS; Nasdaq: CLLS), a
clinical-stage biopharmaceutical company focused on developing
immunotherapies based on gene-edited CAR T-cells (UCART), announced
today that the first patient with Blastic Plasmacytoid Dendritic Cell
Neoplasm (BPDCN) has been dosed in Cellectis’ Phase I clinical study
using the Company’s wholly controlled TALEN® gene edited product
candidate UCART123 at the MD Anderson Cancer Center. UCART123 is the
first allogeneic, “off-the-shelf” gene edited CAR T-cell product
candidate targeting CD123 to be investigated in U.S. clinical trials.

The UCART123 clinical program for BPDCN is led by Dr. Naveen Pemmaraju,
MD, Assistant Professor, Professor Marina Konopleva MD, PhD, and
Professor Hagop Kantarjian, MD, Department Chair, Department of
Leukemia, Division of Cancer Medicine, at the MD Anderson Cancer Center.

The clinical trial will investigate the safety and efficacy of UCART123
in patients with BPDCN in the relapsed, refractory and front-line
setting. BPDCN is a rare and aggressive hematological malignancy
classified in the myeloid diseases among the acute leukemias that are
derived from plasmacytoid dendritic cell precursors. It is a bone marrow
disease that also often affects skin and lymph nodes.

Given its rarity and recent recognition as a distinct
clinicopathological entity, no standardized therapeutic approach has
been established for BPDCN, and the optimal therapy remains to be
defined. Although transient responses are achieved by combination
chemotherapy regimens that are used to treat acute leukemia or lymphoma,
most patients relapse with the drug-resistant disease.

“We are eager to progress through clinical trials with UCART123,
Cellectis’ wholly controlled gene-edited product candidate, next with
the treatment of BPDCN, rare but aggressive entity,” said Dr. Loan
Hoang-Sayag, Cellectis’ Chief Medical Officer. “With this innovative
treatment, the hope is that our “off-the-shelf” approach will transform
the way we think about cancer care and serve as the next step in curing
this disease through the power of gene editing.”

About Cellectis

Cellectis is a clinical-stage biopharmaceutical company focused on
developing a new generation of cancer immunotherapies based on
gene-edited T-cells (UCART). By capitalizing on its 17 years of
expertise in gene editing – built on its flagship TALEN® technology and
pioneering electroporation system PulseAgile – Cellectis uses the power
of the immune system to target and eradicate cancer 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.

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 maintaining regulatory approval to pursue
UCART123 clinical trials, the risk of not obtaining regulatory approvals
to commence clinical studies on UCART123 in other countries or on other
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.

Contacts

Cellectis
Media:
Jennifer Moore, 917-580-1088
VP
of Communications
media@cellectis.com
or
Caitlin
Kasunich, 212-896-1241
KCSA Strategic Communications
ckasunich@kcsa.com
or
IR:
Simon
Harnest, 646-385-9008
VP of Corporate Strategy and Finance
simon.harnest@cellectis.com