DNA/MVA HIV Vaccine
Raising antibodies that are capable of totally blocking natural HIV-1 infections has proven exceedingly difficult and GeoVax has thus focused on raising cellular immune responses in addition to antibodies. GeoVax’s vaccines are recombinant DNA and Modified Vaccinia Ankara (MVA) vaccines that comprise the major HIV-1 subtypes (A, B and C). These vaccines achieve cellular stimulation by priming the cells with an HIV-1-DNA vaccine, thus initially focusing the immune response on the DNA components, and then injecting an HIV-1-MVA live virus vector booster to enhance the immune response. This prime/boost combination elicits protective immune responses in preclinical primate models and holds high promise for eliciting responses that will protect humans against the development of HIV/AIDS.
GeoVax has completed five phase 1 trials combining various combinations and doses of the DNA vaccine with the MVA vaccine in human volunteers for their ability to raise anti-HIV immune responses. All phase 1 testing of these vaccines was successful and supported the initiation of the first phase 2a proof of concept human trial in January 2009 using two doses of DNA and two doses of MVA for prevention of infection by HIV clade B, the most common subtype in North America. GeoVax is also testing its products in a phase 1/2 trial as a therapeutic vaccine, with an expected completion date in mid-2014. In 2012, GeoVax added a GMCSF DNA adjuvant component to its products to significantly enhance efficacy of its vaccines.