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Preclinical Efficacy of Inovio Pharmaceuticals' Smallpox DNA Vaccine Featured in The Journal of Infectious Diseases

December 07, 2010

Inovio's smallpox DNA vaccine provides 100% protection of non-human primates from lethal monkeypox challenge

BLUE BELL, Pa., Dec 07, 2010 (BUSINESS WIRE) -- Inovio Pharmaceuticals, Inc. (NYSE Amex:INO), a leader in the development of therapeutic and preventive vaccines against cancers and infectious diseases, announced today that an article describing 100% protection of non-human primates against a highly pathogenic monkeypox challenge after vaccination with its smallpox DNA vaccine has been published in The Journal of Infectious Diseases. Inovio's DNA vaccine demonstrated strong antibody-based immune responses similar to that of the currently approved live viral vaccine (Dryvax(R)). The study conducted by Inovio scientists and their collaborators is described in this published paper, entitled, "Multivalent Smallpox DNA Vaccine Delivered by Intradermal Electroporation Drives Protective Immunity in Nonhuman Primates Against Lethal Monkeypox Challenge."

The study demonstrated that a synthetic, multivalent, low-injection volume, highly concentrated DNA vaccine delivered by a minimally invasive, novel skin electroporation microarray can generate potent and multi-functional immunity in monkeys and offer protection from a highly pathogenic monkeypox challenge. The diverse, high-titer antibody response produced against eight different DNA-encoded antigens delivered simultaneously as a single formulation has not been previously described in the scientific literature.

The monkeys were immunized three times at one-month intervals and were challenged with a lethal dose of monkeypox virus one month later. All ten animals vaccinated with the DNA vaccine survived the lethal monkeypox challenge, showed significant reduction in the amount of virus circulating in the body, and experienced decreased disease-related sickness in a dose dependent manner (measured by clinical signs of disease and changes in body weight and temperature) as compared to control animals that did not receive the DNA vaccine. Only one macaque from the control group (4) survived the challenge but with lesions still present at the end of the observation period (day 27 post-challenge).

Stanley A. Plotkin, M.D., Emeritus Professor, Wistar Institute and University of Pennsylvania, stated: "These results are remarkable in many ways. DNA for multiple smallpox genes that code for protective antigens was given transcutaneously by electroporation and the responses were protective against monkeypox, a closely related virus. The responses included antibodies, necessary for protection against smallpox, but notable because prior DNA vaccines have had difficulty eliciting antibodies. Finally, this DNA vaccine is actually safer than the old smallpox vaccine and could be useful in the event of a bioterrorist attack necessitating rapid vaccination of people, some of whom might be immunosuppressed; and also if monkeypox is again introduced into the United States."

The threat of a smallpox-based bioterrorist event has heightened the importance of developing a new, safer vaccine approach for these pathogens to complement or replace older poxviral vaccine platforms. The approved live viral vaccine for smallpox has several side effects and is contraindicated in many individuals, which reduces the general acceptance and feasibility of using the currently stockpiled smallpox vaccine to protect the general populace from bioterrorism.

Inovio scientists used gene sequences taken from the smallpox virus to create a multi-antigen DNA vaccine that was delivered using Inovio's proprietary electroporation technology - which uses short, localized and controlled electric pulses to enhance the uptake and effectiveness of DNA vaccines.

A formulation combining eight different DNA plasmids was made possible by technological innovations from VGXI, Inc., a DNA contract manufacturing affiliate of Inovio that enables the production of highly concentrated DNA vaccine products (at a product concentration of greater than 10 mg/mL). The funding for this study was provided by the Defense Threat Reduction Agency (DTRA) of the U.S. Department of Defense.

Dr. J. Joseph Kim, president and CEO of Inovio Pharmaceuticals, said, "The development of novel vaccines for biosecurity concerns such as smallpox has been an important area of development for Inovio's potent DNA vaccines platform. This study indicates the potential to develop a smallpox vaccine with similar efficacy to the important conventional vaccine responsible for eradicating smallpox, but without its notable safety concerns. With further collaborative funding we would look forward to advancing the development of this vaccine candidate to protect humans."

About Smallpox and Monkeypox

Smallpox infection is an exceptionally contagious and highly lethal pathogen, with a lethality rate of > 33% for some forms of smallpox. After its eradication by a vaccination campaign using a live attenuated smallpox vaccine (Dryvax, Wyeth Laboratories), there was a low level of interest in smallpox vaccination by the general public or the scientific community. However, after 11 September 2001, significant concerns over possible bioterrorism with this agent or an engineered smallpox agent reemerged. Despite the success of the Dryvax(R) vaccine, there were numerous vaccine safety concerns relating to changing global health demographics over the last half-century. A less virulent stock consisting of modified vaccinia virus Ankara (MVA) stock has shown improved safety in clinical trials. Although MVA is much less virulent than Dryvax, it remains clear that an alternative non-live approach could provide security for specific compromised populations or in situations where unintended spread is a particular concern.

In addition, monkeypox, a related infectious pathogen with significant mortality in humans, is an emerging concern. Human monkeypox occurs primarily in remote villages of Central and West Africa in proximity to tropical rainforests where there is more frequent contact with infected animals. An outbreak also occurred in the United States in 2003. Monkeypox is usually transmitted to humans from rodents, pets, and primates through contact with the animal's blood or through a bite. There is no proven safe treatment for monkeypox.

About The Journal of Infectious Diseases

Founded in 1904, The Journal of Infectious Diseases is the premier publication in the western hemisphere for original research on the pathogenesis, diagnosis, and treatment of infectious diseases; on the microbes that cause them; and on disorders of host immune mechanisms.

About The Defense Threat Reduction Agency

DTRA is the U.S. Department of Defense's official Combat Support Agency for countering weapons of mass destruction. More information is available at

About Inovio Pharmaceuticals, Inc.

Inovio is developing a new generation of vaccines, called DNA vaccines, to treat and prevent cancers and infectious diseases. These SynCon(TM) vaccines are designed to provide broad cross-strain protection against known as well as newly emergent strains of pathogens such as influenza. These vaccines, in combination with Inovio's proprietary electroporation delivery devices, have been shown to be safe and generate significant immune responses. Inovio's clinical programs include HPV/cervical dysplasia and cancer (therapeutic), avian flu (preventive), and HIV vaccines (both preventive and therapeutic). Inovio is developing universal influenza and other vaccines in collaboration with scientists from the University of Pennsylvania. Other partners and collaborators include Merck, National Cancer Institute, U.S. Military HIV Research Program, HIV Vaccines Trial Network, National Microbiology Laboratory of the Public Health Agency of Canada, and PATH Malaria Vaccine Initiative. More information is available at

This press release contains certain forward-looking statements relating to our business, including our plans to develop electroporation-based drug and gene delivery technologies and DNA vaccines and our capital resources. Actual events or results may differ from the expectations set forth herein as a result of a number of factors, including uncertainties inherent in pre-clinical studies, clinical trials and product development programs (including, but not limited to, the fact that pre-clinical and clinical results referenced in this release may not be indicative of results achievable in other trials or for other indications, that the studies or trials may not be successful or achieve the results desired, that results from one study may not necessarily be reflected or supported by the results of other similar studies and that results from an animal study may not be indicative of results achievable in human studies), the availability of funding to support continuing research and studies in an effort to prove safety and efficacy of electroporation technology as a delivery mechanism or develop viable DNA vaccines, the adequacy of our capital resources, the availability or potential availability of alternative therapies or treatments for the conditions targeted by the company or its collaborators, including alternatives that may be more efficacious or cost-effective than any therapy or treatment that the company and its collaborators hope to develop, evaluation of potential opportunities, issues involving product liability, issues involving patents and whether they or licenses to them will provide the company with meaningful protection from others using the covered technologies, whether such proprietary rights are enforceable or defensible or infringe or allegedly infringe on rights of others or can withstand claims of invalidity and whether the company can finance or devote other significant resources that may be necessary to prosecute, protect or defend them, the level of corporate expenditures, assessments of the company's technology by potential corporate or other partners or collaborators, capital market conditions, our ability to successfully integrate Inovio and VGX Pharmaceuticals, the impact of government healthcare proposals and other factors set forth in our Annual Report on Form 10-K for the year ended December 31, 2009, our Form 10-Q for the nine months ended September 30, 2010, and other regulatory filings from time to time. There can be no assurance that any product in Inovio's pipeline will be successfully developed or manufactured, that final results of clinical studies will be supportive of regulatory approvals required to market licensed products, or that any of the forward-looking information provided herein will be proven accurate.

SOURCE: Inovio Pharmaceuticals, Inc.

For further information: Investors: Inovio Pharmaceuticals Bernie Hertel, 858-410-3101 or Media: Richardson & Associates Jeff Richardson, 805-491-8313

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