Expansion of HIV/AIDS Vaccine Program Announced by GeoVax Labs, Inc.

ATLANTA, April 11, 2011 /PRNewswire/ -- GeoVax Labs, Inc. (OTCQB/OTCBB: GOVX), announced today that it is expanding its preventative HIV/AIDS vaccine development effort in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH) and the HIV Vaccine Trials Network (HVTN).  Specifically, the HVTN plans to clinically test a novel vaccine product developed by GeoVax scientists that expresses human granulocyte-macrophage colony stimulating factor (GM-CSF) in combination with inactivated HIV proteins.  The novel vaccine consists of a recombinant DNA vaccine co-expressing human GM-CSF and non-infectious HIV virus-like-particles. The DNA vaccine is used to prime immune responses that are subsequently boosted by vaccination with a recombinant modified vaccinia Ankara (MVA) vectored vaccine.  The MVA expresses the HIV virus-like-particles, but does not express GM-CSF.  The regimen builds on the GeoVax DNA/MVA vaccine that is currently in Phase 2a clinical testing through the HVTN.

GM-CSF is a cytokine (growth stimulating protein) that serves to expand and mature cells that initiate immune responses and has undergone extensive testing in humans for cancer vaccines.  The GM-CSF-adjuvanted vaccine was added to GeoVax's portfolio because of the outstanding ability of the simian prototype vaccine to induce immune responses that prevented simian immunodeficiency virus (SIV) infection.  In nonhuman primates, the GM-CSF enhanced vaccine achieved protection against SIV in 70% of the animals.  Protection was measured against 12 weekly rectal challenges using a dose of SIV which is estimated to be 30 to 300 times higher than the typical exposure dose of HIV in mucosal transmission in humans.

"For years, the HIV vaccine field has been working with vaccines that elicited immune responses that primarily controlled immunodeficiency virus challenges in infected animals, but did not actually prevent infections. The ultimate goal is to prevent infections.  The co-expression of GM-CSF with the SIV proteins is a vaccine design that appears to be a large step towards reaching this goal," said Dr. Harriet Robinson, Chief Scientific Officer at GeoVax.  "In our trials in nonhuman primates, GM-CSF enhanced the quality of the SIV-specific antibody response.  Antibody is present in blood and tissues and has the potential of blocking SIV before it infects cells.  The GM-CSF-adjuvanted vaccine induced the production of antibodies characterized with increased tightness of antibody binding.  The tightness of antibody binding, known as avidity, can be expressed as an index.  Animals with indices above 40 were protected from infection, whereas animals with lower indices were infected with the number of challenges to infection correlating with their index."

"We are very pleased that the HVTN will be conducting trial HVTN 094 of our GM-CSF adjuvanted vaccine product, which we expect will begin late this year," said Dr. Robert McNally, CEO of GeoVax.  "The HVTN, funded by the NIAID, is the largest worldwide clinical trials network dedicated to the development and testing of HIV/AIDS vaccines.  We are looking forward to working with an excellent team of HVTN trial investigators."

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, overseeing the manufacture 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. GeoVax's vaccines are unique in expressing virus like particles that display the trimeric membrane bound form of the HIV-1 envelope glycoprotein. 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 humoral (antibody) and cellular (cytotoxic T cell) immune responses, as well as, the vaccines' safety. Successful results from 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. Recently GeoVax began enrolling patients in a Phase 1 therapeutic trial for individuals already infected with HIV. For more information, please visit www.geovax.com.

About the HVTN

The HIV Vaccine Trials Network (HVTN) is the largest worldwide clinical trials network dedicated to the development and testing of HIV/AIDS vaccines. The HVTN is an international collaboration that conducts all phases of clinical trials, from evaluating experimental vaccines for safety and the ability to stimulate immune responses, to testing vaccine efficacy. Support for the HVTN comes from the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH). The Network's HIV Vaccine Trial Units are located at leading research institutions in 27 cities on four continents. The Network's headquarters are at the Fred Hutchinson Cancer Research Center in Seattle, Washington.

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.

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SOURCE GeoVax Labs, Inc.