ATLANTA, GA -- (Marketwired) -- 01/23/14 -- GeoVax Labs, Inc. (OTCQB: GOVX) announced today the publication of the results of Phase 2a clinical testing of its JS7/MVA62B AIDS vaccine, GOVX-B11. The article, titled "Specificity and Six-Month Durability of Immune Responses Induced by DNA and Recombinant Modified Vaccinia Ankara Vaccines Expressing HIV-1 Virus-Like Particles" was published on-line in The Journal of Infectious Diseases. An abstract of the article can be located at http://www.ncbi.nlm.nih.gov/pubmed/24403557.
GeoVax is developing two vaccine components: a recombinant DNA vaccine and a recombinant MVA (modified vaccinia Ankara) vaccine. Both produce non-infectious virus-like particles displaying the HIV envelope protein (Env). The vaccines induce humoral (antibody) and cellular (T cell) responses. Antibodies have the potential to block virus before it infects cells. T cells have the potential to recognize and kill cells that become infected by virus that gets past the antibody.
The publication reports the results of two different trial regimens: (1) priming with two doses of the recombinant DNA vaccine and boosting with two doses of the recombinant MVA vaccine (DDMM regimen) and (2) priming and boosting with a total of three doses of the recombinant MVA vaccine (MMM regimen). The Phase 2a trial, initiated in 2009 and completed in 2012, included 299 participants. It was sponsored by National Institutes of Health (NIH) and conducted by the NIH-funded HIV Vaccine Trials Network (HVTN). GeoVax also received support for the preclinical development of its DNA and MVA vaccines from the NIH.
The vaccines showed excellent safety characteristics in both trial regimens. Antibody responses to Env were highest in the MMM group, whereas T cell response rates were highest in the DDMM group. At peak response, 93.2% of the DDMM group and 98.4% of the MMM group had binding antibodies for Env. These binding antibodies were more frequent and of higher magnitude for the more conserved transmembrane subunit of Env (gp41) than the receptor binding subunit (gp120) of Env. Antibody responses showed excellent durability, declining by less than 3-fold from their peak responses at 6 months post vaccination. Responding CD4+ and CD8+ T cells were biased towards Gag and showed good functionality with greater than 70% of responding T cells producing two or three of four tested cytokines.
The comparison of binding antibodies between the two regimens favored the MMM regimen, whereas comparison of cellular immunity favored the DDMM approach. Given that the antibody responses after the 2nd MVA inoculation in the MMM regimen were similar in magnitude to those after the 2nd (and final) MVA inoculation in the DDMM regimen, GeoVax plans to advance a DDMMM regimen with a 3rd MVA boost to advanced clinical trials. The goal of the DDMMM regimen is to optimize both antibody and T cell responses.
"We are encouraged with the results seen in this trial, as the vaccine is safe and predictably induces a wide variety of immune responses directed against HIV," notes Dr. Paul A. Goepfert of the University of Alabama at Birmingham, the study's lead investigator.
"I am very pleased with the reproducibility of our Phase 1 results in a larger Phase 2a trial. I am also encouraged by the longevity of the antibody response to Env," said GeoVax's Chief Scientific Officer, Dr. Harriet L. Robinson. "In the partially successful RV144 trial in Thailand, antibody responses to Env decreased by 10-fold over a six month period, and the waning of the Env-specific antibody was associated with a waning of protection. The greater durability of our antibody could indicate we will achieve more sustained protection."
About GeoVax's Technology
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. Both the DNA and MVA express the three major proteins of the HIV virus: Gag, Pol, and Env, and produce non-infectious virus-like-particles. GeoVax's vaccines are unique in expressing virus-like particles that display the trimeric membrane-bound form of the HIV-1 envelope glycoprotein. 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). Overall, GeoVax's vaccines, in various doses and combinations, have been tested in close to 500 humans.
HIV can affect anyone, regardless of race, gender, age or sexual orientation. 33 million people are currently infected globally and it is estimated that there will be 2.5 million new infections this year. Since the beginning of the epidemic, over a million people in the U.S. have contracted the virus. Every 9 1/2 minutes, someone in the U.S. is infected with HIV. 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 North America. Globally, most infections involve clades AG, B, and C. GeoVax most advanced vaccines under development are designed to function against clade B.
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 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.
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.