Vical Incorporated announced the issuance of U.S. Patent No. 6,586,409, covering DNA vaccination with a novel adjuvant, Vaxfectin. Specific claims include compositions and methods for gene-based vaccination using immunogen-encoding polynucleotides plus the Vaxfectin cationic lipid/co-lipid formulation.

"We are pleased to add a new option to our selection of adjuvants for future DNA vaccine applications," said Vijay B. Samant, Vical's President and Chief Executive Officer. "Vaxfectin is a novel, second-generation, cationic lipid-based adjuvant optimized by Vical to increase the immune response in DNA vaccines. Our options for adjuvants in future vaccines also include proven cationic lipids such as DMRIE/DOPE, which has demonstrated excellent safety in our cancer studies; poloxamers, which have demonstrated both safety and utility as vaccine adjuvants; and of course, alum, which is commonly used as an adjuvant in conventional vaccines.

"Adjuvants are commonly included in conventional vaccines to enhance immune responses or to reduce dosing," added Samant, "and the Vaxfectin formulation has demonstrated such adjuvant activity in DNA vaccines in animal models. It is important to note that the only adjuvant approved in the United States for use in human vaccines is alum, which has been in use for more than 50 years. The major obstacle for approval of additional adjuvants has been safety and the immune reactions they cause at the injection site. Vaxfectin has been widely tested in animal models, including a recent HIV vaccine study in baboons. We look forward to the opportunity to integrate Vaxfectin into future vaccine programs. Our intellectual property, including this new patent, supports the development of a broad range of applications for our platform technology, both through our in-house programs and through our licensees."

The new patent, entitled, "Adjuvant Compositions and Methods for Enhancing Immune Responses to Polynucleotide-Based Vaccines," covers the use of cationic lipid formulations, including Vaxfectin, as adjuvants. This patent adds to Vical's family of patents based on the company's discovery that administering polynucleotides such as DNA or RNA to tissues, without the use of viral delivery vehicles, may cause expression of the proteins encoded by the polynucleotides. Vical holds multiple issued patents covering various aspects of this key discovery, directed toward delivery of both immunogens and biologically active proteins, in the United States and in other key regions.