GeoVax Announces Publication of Repeat Challenge Preclinical Trial in the Journal of Virology
Results Provide Support for Prototype HIV Vaccine Achieving Local Control of Infection
ATLANTA, GA, Mar 19, 2014 (Marketwired via COMTEX) -- GeoVax Labs, Inc. (otcqb:GOVX), an Atlanta-based biotechnology company developing vaccines to prevent and treat HIV/AIDS, announced today the publication of the results of a study in which non-human primates vaccinated with simian prototypes of its HIV vaccine resisted up to 41 rectal exposures to simian immunodeficiency virus (SIV). The article, titled "Local Control of Repeated Rectal Challenges in DNA/MVA Vaccinated Macaques Protected Against a 1st Series of SIV Challenges" was published on-line in the Journal of Virology. An abstract of the article can be located at http://www.ncbi.nlm.nih.gov/pubmed/24574408 . The print version will be available in May.
GeoVax is developing two-component HIV vaccines, consisting of recombinant DNA vaccines used to prime immune responses and recombinant MVA (modified vaccinia Ankara) vaccines that boost the primed response. Both vaccines are unique in producing non-infectious virus-like particles (VLPs) displaying the HIV envelope protein (Env). The vaccines induce both humoral (antibody) and cellular (T cell) responses. Antibodies have the potential to block virus before it infects cells. The T cells have the potential to recognize and kill cells that become infected by virus that gets past the antibody.
The publication reports the resistance to infection during four series of rectal exposures over 3 years in animals vaccinated with two SIV prototypes of the GeoVax HIV vaccines (GOVX-B11 and GOVX-B21). Temporal analyses for virus in blood during the serial exposures revealed transient "blips" of low levels of virus (less than 1000 copies of viral RNA) in all of the test animals. These blips were not associated with the expansion of SIV-specific antibody responses in blood, a sensitive indicator for the establishment of an infection. However, expansions of rectal antibody responses (IgA isotype) were detected in half of the animals. The presence of viral blips that did not lead to outright infection; but, rather were associated with local rectal expansions of antibody, suggest that the vaccine had provided local control of infection.
Dr. Harriet Robinson, Chief Scientific Officer of GeoVax, commented, "A highly desirable characteristic for an HIV vaccine is the ability to locally control an infection. All current vaccines protect by stimulating the expansion of memory responses that control the ability of a virus to cause disease and be transmitted. Because HIV and SIV rapidly establish latent reservoirs and undergo immune escape, it has been proposed that an HIV vaccine will need to be a 'sterilizing' vaccine, or a vaccine that prevents infection in the absence of the expansion of a memory response. Here, the results of 41 exposures over 3 years, suggest that SIV prototypes for the GeoVax vaccine can locally control infections."
"We are truly encouraged by the results suggesting that simian prototypes of our HIV vaccine can protect without the need for sterilizing immunity," Dr. Robinson, continued. "The possibility of local control has been reported for commercial sex workers and discordant couples who remain uninfected despite repeated exposures. The Journal of Virology study is the first to suggest that local control can be achieved by a vaccine. The GOVX-B11 human version of our vaccine has progressed through Phase 2a human clinical trials, and we are working with the HIV Vaccine Trials Network (HVTN) to formulate plans for the next stage of clinical testing. The results of this preclinical study give us further encouragement that we are on a promising path."
GeoVax is a biotechnology company developing vaccines to prevent, and treat, Human Immunodeficiency Virus (HIV) infections. GeoVax's unique, two-component vaccine, a recombinant DNA and a recombinant modified vaccinia Ankara (MVA), is designed to stimulate both anti-HIV antibody and anti-HIV T cell immune responses. GeoVax's DNA and MVA vaccines are used in a prime/boost protocol in which priming is done with the DNA and boosting with the MVA. GeoVax has two vaccines undergoing development: GOVX-B11 and GOVX-B21. Both are for the clade B virus that is prevalent in the developed world. In both vaccines, the DNA and MVA express the three major proteins of the AIDS virus: Gag, Pol, and Env, and produce non-infectious virus-like-particles. GOVX-B21 differs from GOVX-B11 in co-expressing the genetic adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF) with VLPs in the DNA prime. GeoVax's vaccines are currently being tested in human clinical trials, for both preventive and therapeutic applications. Clinical trials for GeoVax's preventive HIV vaccines have been conducted by the US National Institutes of Health-supported HIV Vaccine Trials Network (HVTN) with funding from the National Institute of Allergy and Infectious Disease (NIAID). GOVX-B11 has been evaluated in various doses and combinations in over 400 humans and is the company's lead product for a preventive vaccine. GOVX-B21 has been evaluated in 40 people in a phase 1 dose escalation and regimen trial.
HIV can infect anyone, regardless of race, gender, age or sexual orientation. 33 million people are currently infected globally and it is estimated that there will be over 2 million new infections this year. Since the beginning of the epidemic, over a million people in the U.S. have contracted the virus. Every 10 1/2 minutes, someone in the U.S. is infected with AIDS. Globally, HIV is the top killer among women of reproductive age. HIV is a worldwide disease with different subtypes (or clades) of the virus predominating in different regions of the world. Clade B is the predominant subtype in the Americas, Europe, and Australia. Globally, most infections involve Clades AG, B, and C. GeoVax's most advanced vaccines under development are designed to function against Clade B.
For more information, please visit www.geovax.com .
Forward-Looking Statements Certain statements in this document are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act These statements are based on management's current expectations and are subject to uncertainty and changes in circumstances. Actual results may differ materially from those included in these statements due to a variety of factors, including whether: GeoVax can develop and manufacture its vaccines with the desired characteristics in a timely manner, GeoVax's vaccines will be safe for human use, GeoVax's vaccines will effectively prevent AIDS in humans, vaccines will receive regulatory approvals necessary to be licensed and marketed, GeoVax raises required capital to complete vaccine development, there is development of competitive products that may be more effective or easier to use than GeoVax's products, GeoVax will be able to enter into favorable manufacturing and distribution agreements, and other factors, over which GeoVax has no control. GeoVax assumes no obligation to update these forward-looking statements, and does not intend to do so. More information about these factors is contained in GeoVax's filings with the Securities and Exchange Commission including those set forth at "Risk Factors" in GeoVax's Form 10-K.
Adam S. Holdsworth
SOURCE: GeoVax Labs, Inc.