Inovio Pharmaceuticals Cytomegalovirus (CMV) Synthetic Vaccine Constructs Generate Strong and Broad T-Cell Responses in Preclinical Study

BLUE BELL, Pa., Nov. 26, 2012 /PRNewswire/ -- Inovio Pharmaceuticals, Inc. (NYSE MKT: INO) announced today that testing of multiple synthetic vaccine constructs for cytomegalovirus (CMV) induced robust T cells in mice, demonstrating the potential for a SynCon® DNA vaccine to treat this virus that causes infant death and congenital abnormalities, is associated with cerebral palsy and brain tumors, and is the most common viral infection in organ transplant recipients. CMV is also associated with numerous inflammatory diseases and cancers, and is implicated in hypertension, a major risk factor for cardiovascular diseases.

Results from this preclinical study appear in the peer-reviewed journal, Human Vaccines & Immunotherapeutics, in an article entitled, "Vaccination with synthetic constructs expressing cytomegalovirus immunogens is highly T cell immunogenic in mice."

The genetic complexity of CMV has inhibited the advancement of vaccines for this disease. In this study, DNA vaccine constructs targeting multiple novel CMV antigens were created using Inovio's SynCon® vaccine platform. These SynCon constructs were administered via Inovio's proprietary electroporation-based delivery technology. The vaccine constructs were observed to induce strong and broad CD8+ and CD4+ T cells in an animal model. These findings are vital given the important role T cells play in clearing infection by killing cells that harbor the virus. This is especially crucial in protecting against diseases in different populations such as organ transplant patients that are at high risk from CMV infection.

Dr. J. Joseph Kim, Inovio's President and CEO, said, "Our SynCon® platform has again generated synthetic vaccine candidates that show promise for providing a treatment where there is none. With recent human data showing the powerful killing effect of T cells generated by our therapeutic vaccine for HPV and HPV associated cervical dysplasia and cancer, we look forward to providing Inovio's answer to CMV, a medical problem that has yet to see a vaccine or cure despite 50 years of research."   

Scientific Discussion of Results
Inovio researchers first investigated a novel panel of ten CMV immunogens comprised of mainly surface-associated proteins based on promising prior clinical and preclinical data that had been previously shown to be important for inducing cellular immune responses in CMV infection. To maximize the potential for broadly-reactive immunity, Inovio researchers created SynCon® vaccines for each of the target proteins based on amino acid consensus sequences from multiple variant CMV clinical strains, and excluded those from potentially divergent, highly passaged lab-adapted strains. The researchers adopted the same strategy as was shown previously to enhance protective immune responses against divergent strains of influenza and HIV. The designed target sequences were further genetically optimized at the nucleic acid level.

Researchers observed that vaccination with each CMV construct was highly T cell immunogenic in preclinical proof-of-concept mice studies, generating robust and broad T cell responses as extensively analyzed by the T cell ELISPOT assay. Each antigen produced responses against at least four and as many as 28 different regions of the antigen and, importantly, responses from both CD8+ and CD4+ T cells were observed. This increased diversity and magnitude of cellular responses may be critical for effectively mitigating CMV infection and disease in the transplantation setting.

These data demonstrate that Inovio's next-generation SynCon® DNA vaccine technology is effective at inducing CD8+ T cell responses specific to CMV, in contrast to prior strategies that induced mainly CD4+-dominant responses. Additionally, a majority of epitopes identified for the gB, gH, and gL antigens also contained HLAs that have previously been reported to contribute to the suppression of viremia and amelioration of disease. In summary, the elicitation, identification, and characterization of extensive T cell responses driven by Inovio's CMV SynCon constructs will provide an important tool for guiding clinical development of a CMV vaccine. Further ongoing work will determine how many of the 10 antigens will be selected and taken further for clinical development as well as assess the induction of antibody responses to prevent CMV infection.

About Cytomegalovirus
Cytomegalovirus (CMV) is a member of the herpes family of viruses that spreads from one person to another through the transfer of body fluids. CMV causes a wide variety of infection and illness in healthy adults, in those with compromised immune systems (such as HIV patients), and in pregnant women who can pass the infection to their unborn child (congenital CMV). It is the most common viral infection in solid organ transplant recipients and is considered a causative factor in certain cancers, inflammatory diseases, and cardiovascular/pulmonary diseases. CMV infects over 95% of people in some developing countries. In the US, 50 – 80% of people become infected with CMV by the time they are 40 years old. CMV is the most common viral infection that infants are born with in the United States. The US Institute of Medicine and US National Vaccine Program offices have ranked CMV with the highest priority in terms of potential healthcare dollar savings and improvement in "quality adjusted life years." Although healthy people usually have few symptoms at the time of initial infection, after infection the virus remains in a latent state in the body for the rest of a person's life. The virus can then be transmitted and cause infection through organ donation, or latent virus can become reactivated and cause symptomatic disease.

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.

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CONTACTS:
Investors: Bernie Hertel, Inovio Pharmaceuticals, 858-410-3101, [email protected]
Media: Jeff Richardson, Inovio Pharmaceuticals, 267-440-4211, [email protected] 

SOURCE Inovio Pharmaceuticals, Inc.