Inovio Pharmaceuticals' Dual-Antigen SynCon™ DNA Vaccine for Prostate Cancer Induces Robust Responses in Preclinical Trial

BLUE BELL, Pa., Feb. 2, 2011 /PRNewswire/ -- Inovio Pharmaceuticals, Inc. (NYSE Amex: INO), a leader in the development of therapeutic and preventive vaccines against cancers and infectious diseases, announced today the publication of a scientific paper in the journal Human Vaccines detailing potent immune responses in a preclinical study of Inovio's SynCon™ DNA vaccine for prostate cancer targeting two antigens. While current prostate cancer therapies target single antigens, in this study Inovio tested the hypothesis in mice that a broader collection of antigens, administered with Inovio's electroporation-based delivery technology, would improve the breadth and effectiveness of a prostate cancer immunotherapy.

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The development of a new treatment for prostate cancer would be a significant medical advance given that present treatment options (surgery, radiation and hormone deprivation), while somewhat effective, all carry deleterious side effects and often do not confer long-term cure. Across the United States, there were 218,000 new cases of prostate cancer and more than 32,000 deaths in 2010.

This study, conducted by Inovio scientists and their collaborators, is described in the published paper entitled, "Co-delivery of PSA and PSMA DNA vaccines with electroporation induces potent immune responses." The SynCon™ DNA vaccine evaluated in this study was generated by the creation of PSA and PSMA synthetic consensus immunogens based on human and macaque sequences, which enabled the amino acid sequences of the antigens to differ slightly from the native protein. In humans, this difference may aid in the evasion of self-tolerance while still mounting an anti-tumor immune response.  Mice received two immunizations of highly optimized DNA vaccine delivered by electroporation. Immunogenicity was evaluated one week after the second vaccination. The resultant data showed the induction of strong PSA and PSMA-specific cellular immune responses and also significant antigen specific seroconversion, illustrating that both humoral and cellular immune responses can be generated by this approach.

Inovio previously collaborated with the UK's University of Southampton and Institute of Cancer Research in a study evaluating a DNA vaccine for prostate cancer delivered using Inovio's electroporation delivery technology. The published data from this phase I/II study of a DNA vaccine encoding for human PSMA generated proof-of-concept levels of both antibody and T-cell immune responses in the 30 patients vaccinated in this study.

These proof-of-concept results have recently been supported by positive immunology data from Inovio's phase I clinical study of its multi-antigen SynCon™ DNA vaccine against cervical dysplasias (VGX-3100). In this study, all three dose groups experienced significant antigen-specific antibody and T-cell immune responses against multiple antigens. In the third and final dose group, five of six (83%) patients developed the highest level of T-cell responses achieved by any non-replicating vaccine platform in patients to date.

Dr. J. Joseph Kim, Inovio's President and CEO, said: "This is an important study in which the first SynCon™ DNA vaccine against a cancer target was successfully tested. This immunotherapy targeting more than a single antigen as a treatment for prostate cancer generated strong antibody and T-cell immune responses, which are considered vital to addressing prostate cancer. Taken together with the previous preclinical and clinical data, the current published results support the advancement of this product into a Phase I clinical study."

Inovio's electroporation-based DNA vaccine delivery technology, employed in this study, involves the application of controlled, millisecond electrical pulses to create permeability in the cell membrane and enable dramatic uptake of the vaccine, which has been previously injected into local tissue. Inovio's electroporation-based DNA vaccine delivery systems can increase levels of gene expression (i.e. production of the immune-system-stimulating protein the vaccine was coded to produce) and immune responses of "naked" DNA vaccines by 100-fold or more.

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/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, NIH, HIV Vaccines Trial Network, University of Southampton, and PATH Malaria Vaccine Initiative. More information is available at www.inovio.com.

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.