ATLANTA, Oct. 1 /PRNewswire/ -- Harriet L. Robinson, Ph.D., Chief Scientific Officer at GeoVax Labs, Inc. (OTC Bulletin Board: GOVX), a biotechnology company that creates, develops and tests innovative HIV/AIDS vaccines, presented the results of a study using granulocyte-macrophage colony stimulating factor (GM-CSF) as an adjuvant for the GeoVax DNA/MVA vaccine at the AIDS Vaccine 2010 conference held in Atlanta from September 28 to October 1. The talk, given on Thursday, September 30 in a symposium titled "Blocking HIV/SIV Transmission," reported the findings of a preclinical study conducted at the Yerkes National Primate Research Center at Emory University led by Drs. Lilin Lai, Rama Amara and Robinson. The study was supported by GeoVax with funding provided through an Integrated Preclinical/Clinical AIDS Vaccine Development (IPCAVD) grant from the National Institute of Allergy and Infectious Diseases (NIAID), a division of the National Institutes of Health (NIH).
The team used simian immunodeficiency virus (SIVmac)239 vaccines and a heterologous SIVsmE660 challenge in rhesus macaques to test the utility of co-expressed GM-CSF in the DNA vaccine. The inclusion of the GM-CSF in the vaccine increased protection from 25% to 71%. The protection appeared to completely block infection (versus merely controlling infection), providing what is called "sterilizing" immunity, a highly desirable characteristic for an AIDS vaccine. Impressively, the protection was against 12 weekly intrarectal exposures at a dose estimated to be 100 to 1,000 times higher than typical human exposures during heterosexual transmission.
Dr. Robinson said, "Our results suggest that a GM-CSF-adjuvanted DNA/MVA HIV/AIDS vaccine may be able to achieve much higher levels of prevention of infection than achieved in the ground-breaking study in Thailand in which 31% of participants were protected by a vaccine."
A correlate, or marker, for the immune responses that had blocked infection, was the avidity (tightness of binding) of the vaccine-induced antibodies for the envelope glycoprotein of the challenge virus. The HIV-1 envelope glycoprotein is the "key" for HIV-1 entry into cells. "This is the first time prevention of infection has been associated with a vaccine-induced antibody response and is an exciting result for the AIDS vaccine field where a primary goal has been to raise antibody that can block incoming virus," said Dr. Robinson.
The adjuvanted vaccine study establishes a new benchmark for protection in the preclinical SIV model, achieving a level of protection that is similar to the highly successful polio vaccine. The unadjuvanted HIV-1 form of the vaccine has proven to be both safe and immunogenic in human clinical trials and has advanced to a Phase 2a trial through the US NIH sponsored HIV Vaccine Trials Network. "Historically, the use of GM-CSF in humans has been quite safe," said Dr. Robinson. "Thus there is considerable promise for successful translation of these preclinical findings into human protection."
"We continue to move forward with the current version of our vaccine in Phase 2 human trials and have no plans to alter that program," said Dr. Robert McNally, CEO of GeoVax. "But the data from this study are so compelling that we are accelerating the planning to move the GM-CSF-adjuvanted vaccine into human trials as quickly as possible. Should the current version of our vaccine prove suboptimal, the adjuvanted vaccine will be a strong reserve – and at the very least, it could become the second generation of our HIV vaccine."
About AIDS Vaccine 2010
Since the first conference, organized in Paris in 2000, the AIDS Vaccine conference has become one of the most important annual events for the exchange of scientific information relating to HIV vaccine research and development. Beginning in 2007, the annual conference is organized under the aegis of the Global HIV Vaccine Enterprise and contributes to the goals of the Enterprise by providing a venue for an international exchange of information in HIV vaccine research and development, cross-fertilizing scientific areas of research, increasing coordination and communication among international groups, and monitoring progress in the field. For more information, please visit http://www.hivvaccineenterprise.org/conference/2010.
About GeoVax Labs, Inc.
GeoVax is a biotechnology company developing human vaccines for diseases caused by HIV (Human Immunodeficiency Virus – that leads to AIDS) and other infectious agents. Our goals include developing HIV/AIDS vaccines for global markets, oversee manufacturing and testing of these vaccines under GMP/GLP conditions (FDA guidelines), conducting clinical trials for vaccine safety and effectiveness, and obtaining regulatory approvals to move the product forward. All preventative Phase 1 human clinical trials conducted to date tested various combinations and doses of our DNA and MVA vaccines, their ability to raise anti-HIV immune responses, as well as the vaccines' safety. Successful results from all Phase 1 testing supported the initiation of the first Phase 2 testing. GeoVax's Phase 2 human trial began in January 2009 and will ultimately involve 300 participants at sites in the United States and South America. Earlier this year, patient enrollment began in a Phase 1 therapeutic trial for individuals infected with HIV. Long term, we expect that GeoVax will grant manufacturing and distribution rights in several global markets in return for upfront fees, collaborative development agreements, and royalties on sales and distribution revenues. Internal vaccine manufacturing and distribution will also be considered by GeoVax. For more information, please visit http://www.geovax.com.
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 these 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.
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SOURCE GeoVax Labs, Inc.