INFECTIOUS DISEASES
DNA Vaccines for Infectious Diseases
DNA vaccines use portions of the genetic code of a pathogen to cause the host to produce proteins of the pathogen that may induce an immune response. Compared with conventional vaccines that use live, weakened, or dead pathogens to produce an immune response, this method potentially offers superior safety and ease of manufacturing, as well as convenient storage and handling characteristics. DNA vaccines have the potential to induce potent T-cell responses against target pathogens as well as trigger production of antibodies. Over the past decade, many scientific publications have documented the effectiveness of DNA vaccines in contributing to immune responses in dozens of species, including fish, nonhuman primates and humans. We believe important steps in the validation of DNA vaccines occurred in 2005 when our licensee Aqua Health received Canadian approval to sell its proprietary product, Apex-IHN®, a DNA vaccine to protect farm-raised salmon against infectious hematopoietic necrosis virus, and again in 2007, when our licensee, Merial Limited, received notification of conditional approval from the U.S. Department of Agriculture to market a therapeutic DNA vaccine designed to treat melanoma, a serious form of cancer, in dogs.
Vaccines are generally recognized as the most cost-effective approach for infectious disease healthcare. However, the technical limitations of conventional vaccine approaches have constrained the development of effective vaccines for many diseases. Development of vaccines based on conventional methods requires significant infrastructure in research and manufacturing. In addition, the safety risks associated with certain conventional vaccine approaches may offset their potential benefits. We believe our potential vaccine products may be simpler to manufacture than vaccines made using live viruses or protein subunit approaches including those involving mammalian, avian or insect cell, or egg-based, culture procedures. In addition, our DNA delivery technologies may accelerate certain aspects of vaccine product development such as nonclinical evaluation and manufacturing.
In the broader vaccine marketplace, it is important to note a changing dynamic. Traditionally, vaccines have been predominantly focused on the pediatric market, intended to protect children from diseases that could cause them serious harm. Today, there is a growing interest in vaccines against diseases that may affect adolescents and adults, which include both sexually transmitted diseases and infections that strike opportunistically, such as during pregnancy or in immunocompromised individuals, including the geriatric population. We believe our technologies, because of their potential safety and development timeline advantages, could be ideally suited for the development of this new generation of vaccines.
We currently have active vaccine development programs for cytomegalovirus (CMV) and pandemic iinfluenza. We are pursuing multiple vaccine applications of our proprietary Vaxfectin® adjuvant, both independently and through collaborations.
OTHER VACCINES
We also are developing or have developed vaccines for other infectious diseases. For example, in April 2005 we were awarded a grant from the NIAID for the partial funding of the development of a DNA vaccine against herpes simplex virus. In addition, the NIH has completed its Phase 1 studies in Ebola, West Nile virus, or WNV, and SARS. The NIH has transferred its IND for its SARS DNA vaccine to us and we are currently evaluating our options in continuing the development of that vaccine. Due to the lack of commercial opportunities, we do not plan to, nor do we expect the NIH to pursue further development of a WNV vaccine at this time.
We have also performed preclinical development and completed a Phase 1 clinical trial on an anthrax vaccine designed to provide broader protection against weaponized forms of anthrax. This development work was supported, in part, by two grants received from the NIAID. Because funding needed to support further clinical development is not currently available to us we do not intend to pursue further development of our anthrax vaccine candidate at this time.