GeoVax Trial Results Establish a New Benchmark for Preventative HIV Vaccine Model
Non Human Primate Study Demonstrates Unprecedented 70% Prevention of Infection
ATLANTA, June 8, 2011 /PRNewswire/ - GeoVax Labs, Inc. (OTCBB:GOVX), announced
today the publication of the results of preclinical testing of a simian prototype of its 2nd generation HIV/AIDS vaccine. The article,
titled "Prevention of Infection by a Granulocyte-Macrophage Colony-Stimulating Factor Co-Expressing DNA/Modified Vaccinia Ankara
Simian Immunodeficiency Virus Vaccine," will appear in the July 1 issue of The Journal of Infectious Diseases. A PDF of the
article can be obtained at the following URL: http://jid.oxfordjournals.org/content/204/1/164.full.pdf+html
The publication compares the level of prevention of infection against repeated rectal challenges of simian prototypes of
the GeoVax HIV/AIDS vaccine in the presence and absence of granulocyte-macrophage colony-stimulating factor (GM-CSF). In this non human
primate study, the highly beneficial activity of the GM-CSF was shown by 70% of the group receiving the GM-CSF co-expressing DNA
vaccine resisting infection. GM-CSF is a growth factor that recruits and matures immune system cells that are specialized for
initiating immune responses. GM-CSF was co-expressed in the DNA prime for the recombinant MVA boost. Animals were given two
DNA immunizations, either expressing or not expressing the GM-CSF, followed by two MVA immunizations. The ability of
the two vaccine regimens to prevent infection was then tested by administering 12 weekly rectal challenges with a
dose of virus that infected 30% of unvaccinated animals at each challenge. All of the unvaccinated animals became infected.
The co-expression of the GM-CSF enhanced the ability of vaccine-elicited antibodies to bind to the envelope
protein that mediates entry into cells. This enhanced binding activity correlated with the prevention of infection. The animal with
the least tightly binding antibody was the first to be infected, whereas all animals with binding indices above a certain level were
protected against infection. Antibody is produced by the immune system in response to infections (or vaccines). It is a
clothespin shaped protein that specifically recognizes and blocks microbes, preventing infections. "Having an antibody
activity that correlates with the prevention of infection is an enormous step forward for the development of HIV/AIDS
vaccine," said Dr. Robinson, Chief Scientific Officer of GeoVax. "If one does not have an effective antibody, the
vaccine has to rely on T cells that recognize and kill infected cells. T cells can control infections, but they
do not have the power that antibodies have to prevent infection. The GM-CSF provided the edge for our vaccine
to elicit antibody that could tightly bind to virus." Other prototype vaccines have not achieved the same
level of prevention in non-human primates. Thus, the GM-CSF adjuvanted GeoVax prototype has established
a new standard for prevention of infection.
As recently announced, the GM-CSF co-expressing version of the GeoVax HIV vaccine is entering human trials through the
NIH supported HIV Vaccine Trials Network (HVTN). The protocol, HVTN 094 will test two inoculations of the GM-CSF expressing DNA
vaccine followed by three inoculations of the MVA vaccine. The DNA vaccine co-expresses GM-CSF and non-infectious HIV-like
particles. The MVA vaccine expresses non-infectious HIV-like particles, but does not express GM-CSF. "We are optimistic
that the vaccine will prove as effective at preventing HIV infections in humans as the SIV prototype was in non human
primates" said Dr. Robinson. "The rectal challenges used in the simian model represent 30 to 300 times higher
doses of virus than are experienced during typical HIV transmissions in humans," said Dr. Robinson.
About GeoVax Labs, Inc.
GeoVax is a biotechnology company developing human vaccines for diseases caused by HIV-1 (Human
Immunodeficiency Virus - AIDS) and other infectious agents. Our goals include developing AIDS
vaccines for global markets, manufacturing and testing these vaccines under GMP/GLP conditions
(FDA guidelines), conducting human 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 AIDS vaccines in
human volunteers for their demonstrated ability to raise anti-HIV immune responses as well as for their
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 involve 225 participants at sites in the
United States and South America. 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 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.
The Investor Relations Group:
Janet Vasquez / Laura Colontrelle
"Reproduced with permission - GeoVax Labs, Inc."
GeoVax Labs, Inc.