Inovio Pharmaceuticals Therapeutic Hepatitis B Vaccine Killer T Cells Demonstrate Potential to Clear HBV in Liver
Published: Nov 12, 2012
BLUE BELL, Pa., Nov. 12, 2012 /PRNewswire/ -- Inovio Pharmaceuticals, Inc. (NYSE MKT: INO) announced today that its synthetic hepatitis B (HBV) therapeutic vaccine generated strong T cell responses that eliminated targeted liver cells in mice. This data points to the DNA vaccine's potential to clear HBV infection and thereby prevent liver cancer in humans, an encouraging development given that nearly one-third of the world's population is infected with hepatitis B, with 400 million at risk of developing liver cancer.
Results from this preclinical study appear in the peer-reviewed journal, Cancer Gene Therapy, in an article entitled, "Synthetic DNA immunogen encoding hepatitis B core antigen drives immune response in liver."
In the study, Inovio researchers and collaborators constructed a DNA vaccine encoding an HBV core antigen using the SynCon® vaccine technology and administered it via Inovio's proprietary electroporation-based delivery technology. Researchers observed that the vaccine induced strong "killer" T cells in an animal model. Importantly, those killer T cells, while found systemically, were also present in the liver and provided clearance of HBV antigen-expressing liver cells without inducing liver damage.
The company is also investigating additional HBV antigens to develop a multi-component vaccine that can provide the host immune system multiple targets to clear the hepatitis B virus and infected liver cells.
Dr. J. Joseph Kim, Inovio's President and CEO, said, "Inovio has established a potent immune therapeutics platform. With our recent scientific breakthrough represented by our human data showing the powerful killing effect of T cells generated by our cervical dysplasia therapeutic vaccine, we are encouraged by the published preclinical results generated by our therapeutic vaccine against HBV. Hepatitis B is one of the most important global health problems, and we are excited by the prospect of addressing HBV and other chronic infectious diseases with our vaccines.
Scientific Discussion of Results
With a quarter of a billion people chronically infected worldwide and at risk of developing liver cancer, there is a critical need for an effective HBV therapeutic vaccine that can induce strong antigen-specific immune responses and subsequently deploy the immune responses towards the liver.
In this study, Inovio developed a synthetic DNA vaccine which is encoded for the HBcAg antigen and represents a consensus of the unique HBcAg DNA sequences of all major HBV genotypes (A through E). When delivered by electroporation, researchers first demonstrated that this vaccine elicited strong HBcAg-specific T cell and antibody responses in the periphery (outside of the liver) by ELISpot, ICS and cell proliferation assays. Researchers observed that the vaccination could also induce antigen-specific CD8 and CD4 T cells that produced both IFN-y and TNF-a in the liver, indicating a strong vaccine-induced T cell response was also present in the liver.
Furthermore, study researchers found the vaccine-specific T cells exhibited a killing function, and could migrate to and stay in the liver and cause clearance of target cells without any evidence of liver injury. Taken together, this is the first study to provide evidence that intramuscular immunization can induce killer T cells that can migrate to the liver and eliminate target cells.
About Hepatitis B and Liver Cancer
Although an effective preventive vaccine against HBV infection has existed for over three decades, HBV remains a major epidemic, especially among the people of Asian and African descent. One-third of the world's population has been infected with HBV, with 400 million people chronically infected with the virus and at risk of developing cirrhosis or liver cancer. Currently, the only therapies available for chronically infected individuals are interferon-a and nucleoside analog treatments, which function by controlling viral replication but unfortunately do not clear infection. Interferon can prevent viral replication in only 30% of patients and does so with undesirable side effects.
Liver cancer is the third most common cancer and the most deadly, killing most patients within five years of diagnosis. About 600,000 new cases arise each year. One of the major causes and risk factors for liver cancer is infection by hepatitis B.
About Inovio Pharmaceuticals, Inc.
Inovio is revolutionizing vaccines to prevent and treat today's cancers and challenging infectious diseases. Its SynCon® vaccines are designed to provide universal cross-strain protection against known as well as newly emergent unmatched strains of pathogens such as influenza. These synthetic vaccines, in combination with Inovio's proprietary electroporation delivery, have been shown in humans to generate best-in-class immune responses with a favorable safety profile. Inovio's clinical programs include Phase II studies for cervical dysplasia, leukemia and hepatitis C virus and Phase I studies for influenza and HIV. Partners and collaborators include the University of Pennsylvania, Merck, ChronTech, National Cancer Institute, U.S. Military HIV Research Program, NIH, HIV Vaccines Trial Network, University of Southampton, US Dept. of Homeland Security 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 pre-clinical studies and clinical trials may not commence or be completed in the time periods anticipated, 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, our ability to secure new partnerships and collaborations, capital market conditions, 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, 2011, our Form 10-Q for the quarter ended September 30, 2012, 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.