Introgen wins European patent decision on p53 gene therapeutic

Introgen Therapeutics has announced that it was successful in winning the decision regarding its opposition of European Patent 0 390 323 before the European Patent Office (EPO) in which all claims directed to therapeutic applications of the p53 gene, the active component of Introgen's Advexin molecular therapy, were finally revoked by the EPO's Technical Board of Appeals.

The patent - entitled Detection of Loss of the Wild-Type p53 Gene - and licensed to Schering-Plough Corporation, was directed both to diagnosis of p53 gene mutations and to therapeutic applications of the p53 gene. In today's decision, all claims of the patent that purported to cover therapeutic applications of the p53 gene were finally revoked on the basis of insufficiency of the patent disclosure, affirming an earlier decision by the opposition division of the EPO. This is Introgen's third successful outcome over a period of years in oppositions involving European p53 gene patents controlled by or licensed to Schering-Plough.

Dr. David L. Parker, Introgen's vice president for Intellectual Property said, "This is a very important win for Introgen on the European patent front as this was the last of the three patents we had identified and targeted for revocation several years ago. In light of today's decision, we do not now see any patent impediment to commercialization of Advexin therapy in Europe."

While some diagnostic applications of the p53 gene remain in dispute, the therapeutic claims of this patent can never be reintroduced, according to the EPO proceedings. Diagnostic applications of the p53 gene are not part of Introgen's commercialization plans. Treatments with Introgen's therapies are not dependent on p53 diagnosis.

Introgen has previously reported favorable results of oppositions against this European patent. An opposition is an administrative proceeding conducted by the European patent office for challenging the validity, and requesting patent revocation, of issued European patents.

To date, Introgen controls 29 issued patents and has a large number of pending patents in the United States and in commercially important foreign countries relating to its Advexin therapy. In addition some patents address adenoviral p53 compositions, production, purification and use in the treatment of cancer. Importantly, some of Introgen's patents that are directed to adenoviral processing, purification and formulation are not limited in scope to Ad-p53 and cover generally commercial scale production and formulation of any adenovirus product.