Press Release

Laboratoires Servier and Cellectis sign an agreement in the field of cell engineering.

Biocitech and Neuilly sur Seine, France - October the 08^th, 2007 - Cellectis SA, the French rational genome engineering company, today announced the signature of an agreement with Laboratoires Servier on the engineering of industrial cell lines for use in pharmaceutical research and development.

The agreement covers Laboratoires Servier's use of Cellectis' π10 cell platform and meganuclease recombination system (MRS) for enabling the targeted and reproducible insertion of genes of interest in this cell line. The cell platform will allow Laboratoires Servier to reproducibly and rationally derive consistent ranges of distinct yet closely comparable cell lines for direct use in its industrial processes. The agreement's financial terms have not been disclosed.

The π10 cell platform is based on the CHO K1 line cell, commonly used in industry. Cellectis engineered it and made it programmable so that target genes for drugs will always insert at the same genomic location via meganuclease-mediated recombination. The resulting cells only differ with respect to the inserted gene and thus serve as novel industrial tools for studying drug targets and screening drug candidates.

Meganucleases are a proprietary genome engineering technology developed by Cellectis, it enables the high-precision rewriting of genetic sequences. They are sequence-specific endonucleases with relatively long recognition sites (>18-24 base pairs). This high degree of specificity means that the meganuclease binds to and cuts at a single, predefined site in a given genome and thus avoids the imprecision associated with most other methods of DNA modification (notably transgenesis).

Emmanuel Canet, President for Research & Development at Servier, stated: "We are very pleased to implement this collaboration with Cellectis. It will enable us to access an innovative genome engineering technology and thus boost our ability to discover novel drug candidates. This agreement demonstrates our will to reinforce our corporate resources in the biotech sector".

"We are delighted and proud to sign this agreement with Laboratoires Servier - a prime partner for Cellectis, with its high-performance R&D. This collaboration nicely illustrates Cellectis' development strategy in the industrial tools sector", commented David J.D. Sourdive, Cellectis' Vice President for Corporate Development. " We are delivering as planned and are thus successfully implementing our business model."

About the agreement

Meganucleases can induce surgically-precise modifications in the genome of ex vivo or in vivo cells. The modified π10 platform enables the rapid, reproducible generation of cell lines for industrial uses. The agreement provides Servier with access to the π10 cell platform for in-house use and as a means of deriving new industrial tools.

Cell engineering (notably for the pharmaceutical industry) represents a clearly identified priority market segment for Cellectis. The Servier agreement is part of Cellectis' efforts to deploy its proprietary meganuclease technology in this field and is also in direct line with its strategy.

About Servier

Servier is the leading independent French pharmaceutical company and is chaired by its founder, Jacques Servier, M.D., Pharm.D. The group is present in 140 countries and 82% of Servier's prescription products are sold outside France. The 2006 turnover was €3.3 billion and almost 25% of this sum is being re-invested in R&D. The Servier Group has 19 International Therapeutic Research Centers. Its main therapeutic research orientations are cardiovascular disease, diabetes, neuropsychiatric disorders, cancer and osteoarticular diseases. More information is available at www.servier.com.

About Cellectis

Cellectis SA ( www.cellectis.com) is a world-leading genome engineering & genome surgery company. It focuses on developing new tools for rational reverse genetics and targeted recombination. In particular, Cellectis designs meganucleases (small proteins) that cut DNA at a highly precise, chosen location in a genome and nowhere else. Genomic DNA breaks are repaired naturally by the DNA maintenance system present in all living organisms. Cellectis combines the ability of meganucleases to cut DNA at a single, chosen location with natural DNA repair, in order to offer new-generation products for a wide spectrum of applications:

• Human health: Meganucleases that target a gene responsible for a genetic disease are transferred into human cells, together with a DNA repair matrix which includes the correct sequence for the mutated gene. After the DNA break occurs (which takes just a few minutes), the right sequence is copied into the genome of the patients' cells and the gene is thus repaired. This process - termed "genome surgery" - has a defined time-frame of action with permanent effects. All other transferred material is degraded by natural mechanisms.
• Agrobiotech: The same process used in human healthcare can be applied to plants, with the objective of replacing one gene by another, modifying the gene or shutting it down. The applications developed using Cellectis' technology are essentially focused on improving agronomic features of crops, producing new generations of biofuels and developing better biofibers.
• Biomanufacturing: Biomanufacturing is the production of therapeutic proteins and antibodies using bacteria, yeasts or mammalian cells (mouse, hamster and human cells). This multibillion market has an annual growth rate of over 15%. Cellectis has developed meganucleases that cut the DNA of major production cell lines used in Biomanufacturing, thus enabling the end users (contract manufacturing organizations and biopharmaceutical companies) to shorten their cell line engineering processes, stabilize production yields and thus improve the quality and features of the final product.
• Research tools: Cellectis' technology is particularly useful for studying the function of a gene or set of genes, stably and reproducibly modifying cell lines for screening active compounds, and, more generally, obtaining research results in a controlled, well-defined cellular, molecular and genetic environment.

In the long term, Cellectis intends to become the global leader in genome engineering. To this end, Cellectis is seeking to establish its rational genome engineering approach (based on meganucleases with modified specificity) as an industry standard.
In the short and medium term, Cellectis intends to achieve profitability by commercializing its technology (primarily in the agrobiotech and biomanufacturing fields) and, in parallel, building its own therapeutic pipeline (thus providing shareholders with medium- and long-term value).

To date, Cellectis has entered into more than 45 deals on its genome engineering technologies with major players in the pharma, biotech and agrobiotech industries. Cellectis is listed on the Euronext Alternext market (ticker code: ALCLS). The company currently has 46 staff, including 17 PhDs. For more information on Cellectis, visit our web site: www.cellectis.com

Cellectis' Forward-Looking Statements

This communication expressly or implicitly contains certain forward-looking statements concerning Cellectis SA and its business. Such statements involve certain known and unknown risks, uncertainties and other factors, which could cause the actual results, financial condition, performance or achievements of Cellectis SA to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Cellectis SA is providing this communication as of this date and does not undertake to update any forward-looking statements contained herein as a result of new information, future events or otherwise.

For a discussion of risks and uncertainties which could cause actual results, financial condition, performance or achievements of Cellectis SA to differ from those contained in the forward-looking statements please refer to the Risk Factors ("Facteurs de Risque") section of the prospectus approved by the French Autorité des Marchés Financiers ("AMF") on January 22^nd, 2007 under visa number 07-023, available on the websites of the AMF (http://www.amf-france.org) and Cellectis (http://www.cellectis.com)).