Cellectis and MabQuest Announce Immunotherapy Partnership on New Class of PD-1 Antagonist Monoclonal Antibodies NEW YORK & PULLY, Switzerland--(BUSINESS WIRE)

and MabQuest Announce Immunotherapy Partnership on New Class of PD-1

Antagonist Monoclonal Antibodies

NEW YORK & PULLY, Switzerland--(BUSINESS WIRE)--March 16,

2016--Regulatory News:

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

a biopharmaceutical company focused on developing immunotherapies based

on gene edited CAR T-cells (UCART), and MabQuest SA, a biotech company

focused on the development of antibody-based therapeutic interventions,

announced that they have entered into a research collaboration and

license agreement pertaining to the development of a new class of

monoclonal antibodies targeting PD-1. The action of these PD-1

antibodies is to promote the recovery of T-cells from exhaustion through

a new mechanism of action. This new class of antibodies differs from

currently approved anti-PD-1 mAbs in that they do not block the

PD-1-PD-L1 interaction. These anti-PD-1 mAbs have potential uses for

multiple indications in immunotherapy, including notably treatments for

a variety of cancers. Cellectis plans to use this new class of anti-PD-1

antibodies either in combination therapy with its gene-edited UCART

product candidates or single-agent or in combination with other already

approved immunotherapy drugs.

In vitro studies have shown that the combination of these novel

PD-1 mAbs with currently approved anti-PD-1 mAbs enhances the recovery

of T-cells from exhaustion. Due to their new mechanism of action, these

anti-PD-1 mAbs may be used in combination with other PD-1/PD-L1

inhibitors, such as Nivolumab and Pembrolizumab, or other checkpoints

inhibitors and immunotherapy approaches for boosting the therapeutic

effects of single therapy. Furthermore, this novel class of anti-PD-1

mAbs may represent an alternative and effective therapeutic intervention

in those cancer patients with tumors expressing low levels of PD-L1,

with respect to the currently approved anti-PD-1 mAbs. In addition,

Cellectis intend to combine these PD-1 mAbs with its gene-edited UCART

product candidates to enhance their activity and increase their

The agreement includes a collaboration phase funded by Cellectis whereby

Cellectis and MabQuest will jointly pursue preclinical research on

several candidate antibodies; and a clinical development and

commercialization phase of the best selected antibodies which will be

Under the agreement, MabQuest has granted an exclusive option to

Cellectis. Upon exercise of the option, Cellectis would be granted

worldwide exclusive rights over the family of PD-1 antagonist antibodies

developed under the collaboration for all fields, and further potential

derivatives of these antibodies.

"We are very pleased to have signed this agreement with MabQuest, with

founders and lead scientists who have great expertise in the field of

immunology and monoclonal antibodies," said Andr Choulika, Chairman and

Chief Executive Officer of Cellectis. "This collaboration is an

important building block for our gene-edited UCART product candidates

and for our immunotherapy franchise. This new partnership fits perfectly

into Cellectis' strategy of expanding our focus in the cancer

immunotherapy space with our CAR T-cell based approaches."

"The collaboration agreement with Cellectis is a tremendous opportunity

for MabQuest to move into clinical development with this new class of

anti-PD-1 mAbs. This collaboration will also boost MabQuest's discovery

program to develop additional antibody-based strategies to modulate the

host immune system," said Dr. Giuseppe Pantaleo, President of MabQuest

and Professor of Medicine and Chief of the Service of Immunology and

Allergy at the Lausanne University Hospital, Lausanne, Switzerland.

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 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.

MabQuest SA is a recently established biotech company focused on

developing immune-based interventions aimed at the manipulation and

modulation of the immune system. The company discovery program is to

develop novel antibody candidates targeting single and/or multiple

immunoregulatory mechanisms through immune engineering. The ultimate

goal of the company is to develop new immunotherapies in the fields of

cancer, infectious diseases and immunesenecence.

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.

Jennifer Moore, 917-580-1088

KCSA Strategic Communications

Harnest, 646-385-9008

VP Finance and Investor Relations

Ding, +31-20-5661595

Director of Operations