Vical, University of Washington receive patent for herpes simplex DNA vaccine

SAN DIEGO -- Vical Inc. announced Dec. 22 that it and the University of Washington received U.S. Patent No. 7,628,993 covering DNA vaccines for herpes simplex virus type 2 (HSV-2).

HSV-2 is a sexually transmitted virus that is the leading cause of genital herpes.

Vical is collaborating with the University of Washington School of Medicine and the University of Texas Medical Branch on the preclinical development of an HSV-2 vaccine. It will be designed for use in people already infected with HSV-2, with the goal of reducing or eliminating periodic viral flare-ups and the associated viral shedding and transmission.

The vaccine will be evaluated with Vical's Vaxfectin adjuvant.

The new patent covers DNA vaccines targeting a specific HSV-2 protein, formulated with or without Vical's Vaxfectin adjuvant. It adds to Vical's family of patents in the United States and other key regions based on the company's discovery that administering genetic sequences such as DNA or RNA into the body, without the use of viral delivery vehicles, may cause expression of the proteins encoded by the genetic sequences. Vical has additional issued patents covering the composition and use of the Vaxfectin adjuvant.

DNA vaccines encode certain proteins associated with a target pathogen, rather than using any part of the pathogen itself, and can prime the immune system as well as induce potent antibody and T-cell immune responses. DNA vaccines contain no viral particles, are non-infectious, and can be administered on a repeat basis without unwanted immune responses.

HSV-2 infections are persistent and result in periodic virus shedding. In the United States, at least 40 million people are infected with HSV-2, and approximately 1.6 million people are newly infected each year, with approximately 500,000 of those suffering from disease symptoms. Even higher infection rates are evident in developing countries, with further complications in people also infected with HIV.

There is currently no approved vaccine for HSV-2.

Estimated direct costs of treating HSV-2 in the United States alone are close to $1 billion annually, primarily for drugs and outpatient medical care, plus additional indirect costs of more than $200 million.