PARIS - The Strasbourg-based gene therapy company Transghne SA was granted a U.S. patent titled "Defective adenoviruses and corresponding complementation lines" that covers cell lines (and their method of utilization) designed to eliminate the generation of replicating adenoviruses (also known as replication-competent adenoviruses, or RCAs) during the production of adenoviral vectors for gene therapy.

The company has filed a corresponding patent application with the European Patents Office and has received prior notification of the award of the patent. The protection afforded by the U.S. patent is backdated to May 28, 1993.

Transghne's technology overcomes a particular problem that arises in the preparation of non-replicating adenoviral vectors used for in vivo gene transfer. Preparing these vectors for pharmaceutical applications necessitates the use of "encapsidation," or complementation, cells which include certain elements that have been removed from the vector. This process can generate RCAs through the recombination of viral DNA and the complementation element incorporated in the cell.

US patent No. 6,040,174 describes Transghne's solution for eliminating this risk. Its technique results in the creation of cell lines in which the complementation element is designed to exclude the possibility of generating RCAs during the production of the vector. According to the company, the patent is wide-ranging and protects a large number of primary human cells, such as the human embryo retinal cells used to produce adenoviral vectors.

According to Transghne's managing director, Bernard Gilly, "this patent protects a product and a technology that are essential for the large-scale production of adenoviral vectors, whether they be first- or second-generation ones." It strengthened the company's intellectual property portfolio, he said, which now consists of "patents or patent applications covering replication-competent defective adenoviral vectors, encapsidation cells, adenoviral stock production methods, adenovirus targeting, and processes for constructing adenoviral vectors by homologous recombination."

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