Contre Vir™ Therapeutic Vaccine for AIDS
Current Vaccine Approaches by Others
At present, no AIDS vaccine exists on the market. A vaccine for HIV has been an international priority and is seen as the most likely solution for controlling the AIDS epidemic. However, fifteen years of research and sixty plus clinical trials have failed to yield a vaccine that confers immunity to the patient and clears the infection. In addition, because the vaccines in development are primarily prophylactic vaccines or are designed to be used as adjuncts to other therapies, they will not provide a benefit for those already afflicted with AIDS.
There are four prophylactic vaccine approaches being tested in clinical trials: protein, vector, "whole killed", and DNA vaccines:
- Protein vaccines are composed of recombinant subunits or peptide epitopes of the HIV virus. In general, this approach has failed to generate broad neutralizing antibodies and has not induced a cytotoxic T lymphocyte response. The reasons include dynamic mutations of the HIV envelope glycoproteins, their preservation by a "shield" and relative size of the envelope glycoproteins which cause less MHC-I binding to the host cell wall. The general consensus in the scientific community is that protein vaccines do not have a good chance of success.
- Vector vaccines are genetically engineered viruses and bacteria that code for HIV proteins. The poxvirus vectors are poor inducers of antibodies but do induce a modest cellular immune response. Aventis has a canarypox vaccine in phase II clinical trials. The results of these vaccines have also been disappointing so far, due to the extensive use of envelope glycoprotein encoding which is subject to mutations, divergent clades and poor MHC-I binding.
- The whole killed vaccine approach uses the HIV virus inactivated by chemicals and radiation. The only vaccine developed in this class is Remune® by Immune Response Corporation. Their phase III clinical trial was aborted when the independent monitoring board reported disappointing results when looking at the clinical endpoints. Remune® has been promoted as a therapeutic vaccine, but unlike Contre Vir™, doesn't make a claim of monotherapy and is used as an adjunct to conventional HAART treatment. A few positive findings have been reported, but in the opinion of most scientists do not amount to a breakthrough.
- DNA vaccines are naked DNA plasmids that contain HIV genes. This approach has elicited a modest immune response in preclinical studies, and DNA vaccines developed by Wyeth®, Lederle® and Merck® are in phase I clinical testing. Unfortunately, the "direct DNA" approach, while initially appearing extremely promising, faces the same roadblocks as the VaxGen and Aventis products because of the problems of incorporation of the envelope glycoproteins used. DNA vaccines may also give unpredictable results between given individuals depending on how much of the DNA is neutralized and how much is actually incorporated in the host cell nuclei resulting in transcription/translation.
ImmunoScience, Inc.'s Vaccine
As opposed to the above approaches, Contre Vir™ is unique. Contre Vir™ is a therapeutic AIDS vaccine so it is designed to be given to patients already infected with the HIV virus. Contre Vir™ uses a live HIV-1 virus weakened by a deletion of the nef gene. The nef gene has been shown to be primarily responsible for the ability of the HIV to successfully evade the body's immune response. The deletion of the nef gene enables infected cells to present vaccine HIV antigens in conjunction with surface proteins thus activating CD8 cytotoxic T lymphocytes to kill and clear the virus. Contre Vir™ allows the body to reestablish and reinvigorate the immune response system in order to stop the disease before it becomes fatal. The virus is rendered non-pathogenic by using genetic recombinant techniques, the basis of some of the Company's international patents and patent applications. Furthermore, the processing of conserved internal killer-cell recognition sites allows protection against virtually all the different strains of HIV resulting from mutations.