LONDON -- Introgene BV, of Leiden, the Netherlands, focused on the development of technologies for gene therapy, has signed two further licensing agreements for its PER.C6 gene vector system. Under the deals, Merck & Co., of Whitehouse Station, N.J., and Schering AG, of Berlin, will license the PER.C6 adenoviral packaging cell line in exchange for up-front fees, annual payments and royalties on any adenoviral gene therapy products arising from the agreements.

Introgene claims the company is the first to develop a reliable gene vector production system that avoids the problem of contamination with replication-competent adenoviruses while being able to produce large batches of vectors. Adenoviral vectors offer a higher transduction yield than other vectors, but until recently it was extremely difficult to prevent contamination, which is caused by recombination events between the vector containing the therapeutic gene and the DNA sequences in the cell line required for the production of the vector. The problem of adenoviral vectors being capable of replication is a major hurdle that must be overcome before adenoviral gene therapy products are likely to get regulatory approval.

"We are excited that major pharmaceutical companies continue to recognize the importance of our PER.C6 cell line as a cost-effective, high-yield, uncontaminated production system of recombinant adenovirus," said Dinko Valerio, president and CEO. Introgene has already signed PER.C6 licenses with Genzyme Corp., of Cambridge, Mass.; Rhone-Poulenc Rorer Inc., of Collegeville, Pa.; and Cobra Therapeutics (formerly Therexsys), of Keele, U.K. *