U.S. Navy and U.S. Army to Develop Dengue DNA Vaccine Formulated With Vical's Vaxfectin(R) Adjuvant
SAN DIEGO, Nov 06, 2008 /PRNewswire-FirstCall via COMTEX/ -- VICL | Quote | Chart | News | PowerRating -- Vical Incorporated (Nasdaq: VICL | Quote | Chart | News | PowerRating) today announced that the Naval Medical Research Center (NMRC) plans to conduct preclinical and Phase 1 evaluation of a dengue DNA vaccine formulated with the company's Vaxfectin(R) adjuvant and delivered with the Biojector(R) 2000 needle-free injection system (Bioject Medical Technologies Inc.) (OTC Bulletin Board: BJCT). In support of the program, Vical will manufacture the vaccine and the adjuvant under a $1.3 million contract, and will provide regulatory and clinical expertise. Testing will be performed at the Walter Reed Army Institute of Research (WRAIR) under sponsorship of the U.S. Army Medical Materiel Development Activity (USAMMDA).
"Dengue is the scourge of the tropics today, just as yellow fever was before the widespread use of an effective vaccine," said Vijay B. Samant, President and Chief Executive Officer of Vical. "Dengue presents a serious threat to almost half the world's population living in or traveling to endemic regions. The U.S. government's program, intended to develop a vaccine to protect troops being deployed to dengue-endemic regions, is among the most advanced. The potential for a dengue DNA vaccine has been demonstrated in animal models, and initial safety testing has been completed in humans. Separately, we recently reported encouraging preliminary results from our Phase 1 trial of our H5N1 pandemic influenza DNA vaccines, marking the first time the Vaxfectin(R) adjuvant was tested in humans. We are eager to support the application of our Vaxfectin(R) adjuvant in this important program and hope to advance toward resolution of this significant world health problem."
NMRC scientists developed a DNA vaccine containing genes encoding the pre-membrane (prM) and envelope (E) proteins from the dengue-1 (DEN-1) virus. Following successful challenge testing in nonhuman primates, NMRC conducted a Phase 1 trial of the unadjuvanted monovalent vaccine delivered with the Biojector(R) 2000 needle-free injection system. Preliminary results indicated that the vaccine was safe and well-tolerated at both the 1 mg low dose and 5 mg high dose tested, but even at the high dose induced only low levels of neutralizing antibody titers in less than half of the animals. Under a Collaborative Research and Development Agreement (CRADA) with Vical, the NMRC developed a tetravalent dengue vaccine containing prM and E genes for all four serotypes of dengue, and formulated with the Vaxfectin(R) adjuvant. Nonhuman primate immunogenicity and challenge data with the tetravalent DNA vaccine, formulated with or without the Vaxfectin(R) adjuvant and delivered by needle-free injection using the Biojector(R) 2000, were promising.
Four of four (100%) rhesus macaques receiving the Vaxfectin(R)-formulated vaccine developed neutralizing antibodies to all four serotypes of dengue one month after the second injection (Day 56), and were highly protected against challenge, exhibiting very limited viremia (group mean 0.75 days). Only one of four (25%) macaques receiving the unformulated vaccine developed neutralizing antibodies to all four serotypes of dengue one month after the second injection (Day 56), and were partially protected against challenge, exhibiting limited viremia (group mean 2.00 days). The unvaccinated control macaques did not develop any neutralizing antibodies, and were unprotected against challenge, exhibiting typical viremia (group mean 3.33 days). The next step in this program will be to advance this vaccine to Phase 1 human testing.
About Dengue
Dengue virus infects up to 100 million people each year. Its impact is magnified by the lack of effective antiviral drugs and vaccines. As many as half a million people develop severe dengue disease each year, causing tens of thousands of deaths, particularly where healthcare is limited.
Dengue fever can be caused by any one of four serotypes of dengue virus: DEN-1, DEN-2, DEN-3 and DEN-4. These viruses are part of the Flavivirus family, which includes West Nile virus and yellow fever virus. Dengue virus is spread by mosquitoes, and is most common during the rainy seasons throughout the world's tropical and subtropical regions. Dengue does not spread directly from person to person. An individual infected by one serotype of dengue virus develops lifelong immunity against that serotype, but not against other serotypes.
Symptoms of classic dengue fever include high fever (up to 105 degrees F), severe headache and/or pain behind the eyes, severe joint and muscle pain, nausea and vomiting. A few days after fever onset, a rash often develops over most of the body and lasts for one to two days. The rash can reappear several days later. These symptoms typically begin within a week after infection, and usually resolve without treatment.
Dengue hemorrhagic fever is a more serious form of disease which can include all of the symptoms of classic dengue fever plus noticeable damage to blood vessels and lymph vessels, bleeding from the nose and gums, and conspicuous bruising under the skin. Dengue hemorrhagic fever can lead to death. The most severe form of dengue disease is dengue shock syndrome, which includes all of the symptoms of classic dengue and dengue hemorrhagic fever, plus leaking of blood outside of blood vessels, extensive bleeding, and shock caused by extremely low blood pressure. Dengue shock syndrome most often occurs in children infected for a second time (with a different serotype of dengue), and can be fatal. Dengue disease, including classic dengue, dengue hemorrhagic fever and dengue shock syndrome, is increasing in both incidence and severity throughout many tropical regions of the world, especially in Africa, the Indian subcontinent, and Southeast Asia.
NMRC Dengue Focus
The Naval Medical Research Center conducts research into the many health threats to members of the U.S. military. The Infectious Diseases Directorate conducts research on infectious diseases that are considered to be significant threats to deployed sailors, marines, soldiers, and airmen. The primary focus of the Viral Diseases Division is on the development of a vaccine to prevent dengue fever, with a major emphasis on novel vaccine technologies and adjuvants.
About Vical
Vical researches and develops biopharmaceutical products based on its patented DNA delivery technologies for the prevention and treatment of serious or life-threatening diseases. Potential applications of the company's DNA delivery technology include DNA vaccines for infectious diseases or cancer, in which the expressed protein is an immunogen; cancer immunotherapeutics, in which the expressed protein is an immune system stimulant; and cardiovascular therapies, in which the expressed protein is an angiogenic growth factor. The company is developing certain infectious disease vaccines and cancer therapeutics internally. In addition, the company collaborates with major pharmaceutical companies and biotechnology companies that give it access to complementary technologies or greater resources. These strategic partnerships provide the company with mutually beneficial opportunities to expand its product pipeline and address significant unmet medical needs. Additional information on Vical is available at http://www.vical.com.
This press release contains forward-looking statements subject to risks and uncertainties that could cause actual results to differ materially from those projected. Forward-looking statements include statements about the NMRC's, the USAMMDA's and the WRAIR's plans for a continued development of a DNA vaccine for dengue, and the potential effect of the company's Vaxfectin(R) adjuvant on vaccine performance. Risks and uncertainties include whether the NMRC, WRAIR, USAMMDA, Vical or others will continue development of the dengue vaccine; whether USAMMDA will sponsor and the NMRC will complete preclinical and Phase 1 testing of a tetravalent, Vaxfectin(R)-formulated DNA vaccine for dengue; whether Vaxfectin(R) or other results in animal studies can be duplicated in human clinical trials; whether Vaxfectin(R) will improve the immune responses against the specific dengue vaccine targets; whether the dengue vaccine will be effective in protecting humans against dengue infection or disease; whether the dengue vaccine will achieve the safety and immunogenicity endpoints in the Phase 1 trial; whether Vical or its collaborative partners will seek or gain approval to market any product candidates; whether Vical or its collaborative partners will succeed in marketing any product candidates; and additional risks set forth in the company's filings with the Securities and Exchange Commission. These forward- looking statements represent the company's judgment as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.