Inovio Pharmaceuticals' Prostate Cancer DNA Vaccine Demonstrates Strong T Cell Responses in Monkeys; Company on Track for Phase I Clinical Trial

BLUE BELL, Pa., June 29, 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 that its therapeutic DNA vaccine for prostate cancer showed remarkable immune responses in monkeys, following similarly strong, antigen-specific and sustainable T cell levels in previously reported data from earlier animal studies. The data was presented by Dr. J. Joseph Kim, Ph.D., president & CEO of Inovio, at the BIO International Convention in Washington, DC. The strength of this new large animal data reinforces Inovio's plan to start a Phase I clinical trial for this prostate cancer DNA vaccine (INO-5150) by mid-year 2012.

In this monkey trial, vaccinations with INO-5150, Inovio's SynCon™ therapeutic DNA vaccine for prostate cancer, generated strong and robust T cell immune responses. The level of T cell responses from this INO-5150 study was similar to the level of T cell responses observed from a previously conducted monkey study of VGX-3100, Inovio's Phase II-stage therapeutic vaccine for cervical cancer and dysplasia. In a Phase I study, VGX-3100 generated best-in-class T cell responses, which were persistent through the complete study duration of nine months.

In a prior study in mice, INO-5150 immunization induced potent antibody and T cell responses, providing initial evidence that its concept for a therapeutic DNA vaccine comprising a broader collection of antigens, administered with Inovio's electroporation-based delivery technology, would improve the breadth and effectiveness of a prostate cancer immunotherapy. Furthermore, 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 novel approach may help the body's immune system to overcome its "self-tolerance" of cancerous cells created in the body by recognizing these cells as being foreign and mounting an immune response to clear these cells.

Inovio is currently manufacturing clinical grade INO-5150 with the goal of launching its planned Phase I study in mid-2012.

Dr. Kim said: "The immune response data achieved by our SynCon™ prostate cancer vaccine in this large animal study is exceptional. It reinforces the repeatedly and consistently strong, long-lasting immune responses achieved by Inovio's DNA vaccine platform against multiple cancers as well as other diseases. We are optimistic about the potential of this therapeutic vaccine in our planned prostate cancer human study and broadly speaking for cancers in general, including our currently progressing cervical cancer and leukemia Phase II clinical studies."

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.

Inovio's Cancer Portfolio...Into Phase II and Diverse Cancer Types

Inovio's SynCon™ DNA vaccine technology has created the potential for a new generation of cancer vaccines. Inovio is moving forward with two DNA vaccines in Phase II development:

• VGX-3100, Inovio's proprietary DNA vaccine for treating cervical dysplasia and cancer caused by human papillomavirus (HPV); and,
• pWT1, a DNA vaccine for treating acute and chronic myeloid leukemia (CML and AML). Inovio is also working with partners on this DNA vaccine using its electroporation delivery technology.

For its cervical cancer vaccine, Inovio is currently conducting a randomized, placebo controlled, double blind Phase II study evaluating the effects of VGX-3100 treatment on the clearance of moderate or severe cervical intraepithelial neoplasia (CIN 2/3) cervical lesions. A total of 148 patients will be enrolled in 25 study centers in the US, Korea, South Africa, Australia, and Canada.

In a previous Phase I study of 18 adult females with CIN 2/3 stages, 72% of vaccinated subjects (13 of 18) developed significant antigen-specific T-cell responses during the first four months of treatment (each patient was vaccinated at months 0, 1, and 3) by standardized T cell assay. Furthermore, 91% of evaluable responders (10 of 11) displayed strong and persistent memory T-cell responses at month 9, with strong T cell responses.

In the Phase I escalating dose 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.

The leukemia study, pWT1, utilizing Inovio's electroporation delivery technology, is a single dose, Phase II trial currently recruiting up to 170 CML and AML patients. This leukemia trial is being conducted in a collaboration with the University of Southampton. All vaccinated subjects will initially receive six doses of two DNA vaccines (called p.DOM-WT1-37 and p.DOM-WT1-126) delivered at four week intervals. Vaccine responders may continue with booster vaccinations every three months out to 24 months. The study will also have control AML/CML patients enrolled across the two arms as non-vaccinated controls for comparison. The primary endpoints will be molecular response to a disease marker called BCR-ABL in CML patients and time to disease progression in AML patients. The study will also monitor WT1 transcript levels, immune responses to the WT1 antigen, time to progression and overall survival, and two-year survival in the AML group. The trial will take place at several sites in the UK.

About Inovio Pharmaceuticals, Inc.

Inovio is developing a new generation of vaccines, called DNA vaccines, to treat and prevent cancers and infectious diseases. Its 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 clinical programs include three Phase II studies for vaccines treating cervical dysplasia/cancer, hepatitis C virus, and leukemia. Other clinical programs target influenza (preventive) and HIV (preventive and therapeutic). Inovio 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, 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, 2010, our Form 10-Q for the three months ended March 31, 2011, 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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SOURCE Inovio Pharmaceuticals, Inc.