SBIR-STTR Award

The long-term goal of this study is to determine whether HIV-I based vectors can prevent AIDS disease progression in HIV-infected individuals. We have shown that an HIV vector carrying an anti-HIV antisense genetic payload (VRX496) can transduce primary human CD4 T cells by over 90 percent transduction efficiency, as measured by FACS two weeks after transduction. CD4 T cells transduced in this manner were directly challenged with wt-HIV and shown to inhibit HIV-I replication in normal primary CD4 T cells by over three logarithmic units of p24. Similar inhibitory effects on wt-HIV replication were seen when transduced cells were challenged with various primary strains of HIV. Significantly, primary CD4 T cells transduced with VRX496 were found to be resistant to productive HIV infection and hence, had a survival advantage over cells not modified with the vector. Furthermore, preliminary data have shown similar effects of VRX496 in CD4 T cells derived from one HIV-infected donor. An important goal for the clinical translation of this class of vectors would be to characterize their inhibitory effects on the pathogenic virus present in cells derived from HIV-infected individuals. The specific goal of this project is to fully characterize the inhibitory effects of VRX496 in primary human CD4 T cells derived from HIV-infected donors that differ by their clinical status. CD4 T cells isolated from HIV infected donors discordant in viral load, CD4 count and HAART therapy will be transduced with VRX496 and the biological and anti-HIV effects characterized. Characterization of the effects of VRX496 in the cells from a wide variety of HIV-infected patients ex vivo will provide important data for rational design of future in vivo clinical studies. PROPOSED COMERCIAL APPLICATIONS: HIV-1 based vectors can deliver payload genes into primary human cells with very high efficiency. When a anti-HIV payload gene is deliv ered into primary CD4+ T cells that are then infected with wt-HIV, viral replication can be inhibited by over 2 logarithmic units of p24, as measured by ELISA antigen capture assay. One of the potential commercial applications of the technology is for the treatment of individuals infected with AIDS. The technology can also be used for gene therapy of other diseases such as cancer because this class of vectors can efficiently transduce many cell types.

Thesaurus Terms:
AIDS therapy, HIV infection, antisense nucleic acid, gene delivery system, gene therapy, human immunodeficiency virus 1, immunogenetics, transfection, virus genetics antiAIDS agent, gene expression, genetic transduction, helper T lymphocyte clinical research, human subject, tissue /cell culture

HIV infects 40 million people worldwide. In the United States (U.S.), it is estimated that almost one million people are infected with HIV. The mortality due to HIV/AIDS is estimated to be approximately three (3) million deaths annually worldwide, with 15,000 deaths per year in the U.S. The current standard of care for treatment of HIV is HAART, or highly active antiretroviral therapy. However, HAART is very expensive and requires a cumbersome dosing regimen. More importantly, an increasing number of resistant HIV strains are emerging as a result of drug therapy, and these resistant strains are being transmitted to newly infected individuals. This subpopulation of HIV drug-resistant patients has no treatment alternatives and therefore has a very poor prognosis. Our overall goal is to demonstrate the safety and efficacy of HIV-1-based vectors in delaying or preventing the onset of AIDS, the disease caused by HIV. Our technology uses HIV as a backbone to deliver an anti-HIV gene to infected CD4 T cells, which are the target cells for HIV replication. We have demonstrated in studies supported by Phase I SBIR funding that an HIV vector carrying an anti- HIV antisense genetic payload (VRX496) effectively inhibits productive HIV replication in patient CD4 T cells independent of patient viral load, CD4 count, and virus tropism. The key technological objectives of the proposed studies in this grant are to characterize the risk/benefit ratio of our therapy, and develop and validate the technology in-house for large-scale patient cell processing in preparation for U.S. efficacy clinical trials. To this end, our specific aims are: 1) determine whether lentiviral gene transfer induces clonal T cell lymphoproliferation in vivo, and catalog insertion sites in healthy and HIV-infected adult and pediatric donors, 2) evaluate the efficacy of our therapy in terms of immune reconstitution by measuring the immunological responses in VRX496-treated patients longitudinally, and 3) develop and validate the technology for in house large-scale cell processing for gene therapy treatment of HIV. These three key objectives are closely associated with the overall product safety and efficacy, which is an important step in moving forward to making our therapy available to those patients who would otherwise have no alternative treatment options.

Thesaurus Terms:
AIDS therapy, HIV infection, gene therapy, human therapy evaluation, therapy design /development T lymphocyte, leukocyte activation /transformation, longitudinal human study, mass tissue /cell culture, method development, pediatric AIDS clinical research, enzyme linked immunosorbent assay, human subject, patient oriented research