Vical announces issuance of US patent for HSV-2 vaccine

Vical Incorporated announced today the issuance of U.S. Patent No. 7,879,339, assigned to Vical and the University of Washington, covering DNA vaccines for herpes simplex virus type 2 (HSV-2). Vical is collaborating with the University of Washington School of Medicine and the Sealy Center for Vaccine Development, both centers of excellence in herpes virus research, under a previously disclosed grant on the preclinical development of an HSV-2 vaccine. The initial focus will be for 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.

HSV-2 is a sexually transmitted virus which is the leading cause of genital herpes. Approximately one out of every six individuals in the United States and an estimated one out of every four worldwide is infected by HSV-2 before age 50. HSV-2 infections are persistent and result in periodic virus shedding. HSV-2 infection also significantly increases the risk of acquiring HIV-1. 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. HSV-2 is a sexually transmitted virus which is the leading cause of genital herpes.

There is currently no approved vaccine for HSV-2. Although antiviral regimens have become a standard of care, their inconvenience, cumulative cost over the years and potential for drug resistance highlight the need for safe, new approaches to reducing HSV-2 lesions, shedding, and transmission. 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.

The new '339 patent covers DNA vaccines containing the HSV-2 UL49 gene, which encodes the VP22 tegument 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.

The preclinical development is being funded under a two-year, $2.0 million Phase II Small Business Technology Transfer (STTR) grant awarded in 2008 by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH), an agency of the U.S. Department of Health and Human Services. The grant period was extended to allow preclinical development to continue for a third year. The $2.0 million Phase II STTR grant supplements the $0.3 million awarded to Vical in 2005 for the HSV-2 vaccine program under a Phase I STTR grant from the NIAID, which partially funded Vical's initial development of the HSV-2 vaccine.