Cellectis Files First Clinical Trial Application for UCART19, an Allogeneic Gene Edited CAR T-Cell Product for Hematological Malignancies

New York, December 23, 2015 – Cellectis (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 Officer, Cellectis.

"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.

About UCART19

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 product.

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 clinical program.

Information about ongoing clinical trials are publically available on dedicated websites such as:

www.clinicaltrials.gov in the U.S.

www.clinicaltrialsregister.eu in Europe