Preclinical Efficacy of Inovio Pharmaceuticals’ Chikungunya DNA Vaccine Featured in PLoS Neglected Tropical Diseases

DNA vaccine induces protective antibody and T-cell immune responses in non-human primates against Chikungunya virus

BLUE BELL, PA, USA | January 12, 2011 | Inovio Pharmaceuticals, Inc. (NYSE Amex: INO), a leader in the development of novel therapeutic and preventive vaccines against cancers and infectious diseases, announced today the publication of a scientific paper highlighting positive results from Inovio’s multi-antigen Chikungunya virus (CHIKV) DNA vaccine in PLoS Neglected Tropical Diseases. The paper, entitled “A DNA vaccine against Chikungunya virus is protective in mice and induces neutralizing antibodies in mice and nonhuman primates,” authored by Inovio scientists and collaborators, describes the ability of the vaccine to induce robust antibody and T-cell immune responses and provide 100% protection of mice against a challenge with this tropical infectious disease. Additionally, vaccine studies in rhesus macaques demonstrated generation of strong neutralizing antibody responses which mimicked those observed in CHIKV-infected human patients who subsequently recovered from this disease. These results demonstrate the ability of Inovio’s DNA vaccine to provide protection and protective immune responses in two different preclinical models.

CHIKV is an emerging mosquito-borne virus indigenous to tropical Africa and Asia. Acute illness is characterized by fever, arthralgia (pain in a joint), conjunctivitis (eye inflammation), rash, and sometimes arthritis. Relatively little is known about the antigenic targets for immunity and no licensed vaccines or therapeutics are currently available. Considering the potential for pandemic spread, understanding the development of immunity is paramount to the development of effective vaccines against CHIKV.

In this study, the research team isolated CHIKV from an acutely infected human patient and used this newly isolated virus to develop a virus neutralization assay and a challenge stock. The CHIKV challenge stock was used to establish a mouse infection model and study disease development. The candidate CHIKV vaccine developed by the researchers and tested in the mouse and macaque models is a SynCon™ synthetic DNA vaccine consisting of a single consensus envelope construct that expresses all three of the CHIKV envelope glycoproteins (E3+E2+E1). The vaccine is delivered by in vivo electroporation.

Dr. J. Joseph Kim, president and CEO of Inovio Pharmaceuticals, said, “Inovio has been researching and developing novel vaccine candidates for several emerging infectious diseases with pandemic potential such as Chikungunya virus utilizing our potent DNA vaccine development platform. These published data suggest a protective role for antibodies against Chikungunya, a re-emerging health threat in both developing and developed countries, and support further development of Inovio’s DNA vaccine for this disease.”

About Chikungunya Virus

CHIKV has been identified as the virus responsible for major epidemics in both Africa and Southeast Asia and continues to be a re-emerging virus of great interest to public health. While the Aedes aegypti mosquito is its primary vector, recent evidence suggests that other carriers can transmit CHIKV. Significantly, exposed travelers returning from the affected areas to Europe, the US, Canada, Hong Kong, and numerous other countries have carried the virus into these new territories.

Upon infection, Chikungunya fever tends to present itself in two phases. The first stage is acute, with symptoms including abrupt onset of fever, joint pain and, in some cases, rash. It causes intense joint and muscular pain that makes movement very difficult. The second stage, experienced by most but not all, is persistent, causing disabling polyarthritis. Ninety-five percent (95%) of infected adults are symptomatic after infection; of these most become disabled for weeks to months as a result of decreased dexterity, loss of mobility, and delayed reaction.

Several vaccines are in development against CHIKV, such as a formalin-inactivated vaccine, a virus-like particle vaccine and a live attenuated vaccine. None have advanced to clinical development and therefore illustrate an important area of need. While the threat of a pandemic continues to engage the public’s attention, the peculiar problems associated with the more immediate and very real seasonal epidemics are also worthy of consideration. Specifically, there are limited viral strains that have been characterized and available for laboratory study as well as knowledge of immune responses induced to the virus.

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™ 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-caused cervical dysplasia and cancer (therapeutic), avian flu (preventive), and HIV vaccines (both preventive and therapeutic). Inovio is developing DNA 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, NIH, HIV Vaccines Trial Network, National Microbiology Laboratory of the Public Health Agency of Canada, and PATH Malaria Vaccine Initiative. More information is available at

SOURCE: Inovio Pharmaceuticals

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