Successful GMP Production Process for UCART19

New York, October 28, 2015 – Cellectis (Alternext: ALCLS – Nasdaq: CLLS) today announced that a series of three production runs of UCART19, its lead TALEN® gene edited product candidate, was performed, confirming the implementation of Cellectis' manufacturing process in GMP conditions.

The manufacturing process for Cellectis' allogeneic CAR T-cell product line, Universal CARTs or UCARTs, yields frozen, off-the-shelf, allogeneic, engineered CAR T-cells. UCARTs are meant to be readily available CAR T-cells for a large patient population. The TALEN®-based gene editing (knock-out of the TCR-alpha and CD52 genes) is designed to suppress T-cell alloreactivity and confer resistance to alemtuzumab to the T-cells. This important milestone shows that UCARTs can be manufactured in GMP conditions. It also demonstrates the industrial production of UCART19, as well as the capacity of Cellectis' pipeline of UCART product candidates to be manufactured for clinical investigations.

"It is very exciting to lead a novel allogeneic gene therapy platform at the critical time when a R&D concept is translated into a GMP clinical grade industrial product to be investigated in clinical studies," said Arjan Roozen, Vice President, GMP Solutions and Manufacturing.

"Cellectis has reached a critical milestone both for the Company and our industry, creating new opportunities for patients. Historically, cell-based therapies have grown in the world of individual grafts. With TALEN®-based gene editing they have now started moving toward that of industrial pharmaceutical products broadly available to patients, and Cellectis, as a leading company in the field of gene editing, is at the forefront of this evolution," added David J.D. Sourdive, Executive Vice President, Corporate Development.

About UCART19

UCART19 is a potential best-in-class allogeneic engineered T-cell product for treatment of CD19 expressing hematologic malignancies, initially developed in Chronic lymphocytic leukemia (CLL) and Acute lymphoblastic leukemia (ALL). Servier has an option under the collaboration agreement to acquire the exclusive rights to further develop and commercialize UCART19. Engineered allogeneic CD19 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.

Arjan Roozen, Vice President GMP Solutions and Manufacturing

Arjan Roozen received a BSc degree in molecular microbiology from Larenstein, Velp in The Netherlands. Arjan joined Cellectis in March 2015. In his present position of VP GMP Solutions & Manufacturing, he is responsible for all GMP pharmaceutical manufacturing activities including the biological raw materials.

Before joining Cellectis, Arjan worked for over 20 years at different biotechnology departments at Centocor, Solvay Pharmaceuticals, Biogen Idec, Crucell, Proxy laboratories and Pharmacell and gained significant experience in QC, QA and manufacturing GMP aspects. The last 4 years within Pharmacell, Arjan Roozen was responsible for GMP operations involved in significant number of cell therapy technology transfer projects as well as responsible for cell therapy commercial products. He was also involved in regulatory audit and filings for EMA and FDA.