Cellectis announces delivery of a meganuclease targeting the RAG1 to Professor Luigi's group

Cellectis announces delivery of a meganuclease targeting the RAG1 gene (responsible for a severe immunodeficiency) to Professor Luigi Notarangelo's research group at the Children’s Hospital Boston (USA).

Biocitech, France - November 15 2007 - Cellectis SA, the rational genome engineering company specializing in the production of meganuclease recombination systems and in meganuclease engineering, today announced the delivery of a meganuclease targeting the RAG1 gene to Professor Luigi Notarangelo's research group at the Children’s Hospital Boston (USA).

The RAG1 gene is mutated in certain severe combined immunodeficiency (SCID) patients. To date, the only possible therapeutic response for these patients has been a bone marrow transplant, for reconstitution of their entire immune system. In 2000, new hope arose for patients with X-SCID (a type of SCID syndrome, see below), following promising gene therapy trials performed in France. However, several of the treated patients developed leukemia. These severe adverse events appear to be linked to insertion of the gene therapy vector in the vicinity of a particular gene. Meganucleases enable an alternative approach based on correction of the defective gene itself, rather than random insertion of a "gene drug". The meganuclease technology should enable avoidance of the above-mentioned adverse event and should help make the gene therapy approach safer.

In August, Cellectis had already delivered a meganuclease to Professor Alain Fischer's group (INSERM Unit U768 at the Necker Children's Hospital in Paris) in order to test its potential ability to repair the defective gene in cell lines carrying a X-SCID mutation. X-SCID patients represent another class of SCID patients, in whom the disease is linked to a mutation in the IL2RG gene. Meganucleases targeting the RAG1 gene address another type of patient but this new collaboration demonstrated Cellectis' emphasis on SCID syndromes in
general. Indeed, Cellectis is strengthening its commitment to finding a treatment for this type of disease and, in the short- to mid-term, intends to evidence clinical proof of concept for its genome surgery approach in humans.