755. Phase II Clinical Trial Demonstrates the Safety and Tolerability of Multiple Doses of Autologous CD4+ T Cells Transduced with VRX496, a Lentiviral Vector Delivering Anti-HIV Antisense in Patients Failing 1 or More HAART Treatment

Abstract

Gene therapy for HIV-1 infection has been proposed as an alternative to antiretroviral drug regimens due to emerging drug resistance and toxicity that raises concerns about HAART as a long term therapy. We have previously reported the successful completion of our Phase I clinical trial testing the safety and tolerability of a single dose of autologous HIV infected CD4+ T cells transduced with a lentiviral vector delivery system expressing a 937-base antisense gene against the HIV envelope (VRX496) for use in T cell therapy for HIV/AIDS. These results have lead us to initiate a Phase II clinical trial to evaluate the safety, tolerability, and biological activity of repeated infusions (4 or 8 doses) of autologous VRX496 transduced T cells. The study will enroll up to 40 male and female HIV-positive subjects in up to 8 centers. Subjects will be 18 years of age and over who have failed or are intolerant to at least one triple combination of antiretroviral drugs. Subjects will have, a viral load between 5,000 and 200,000 copies/ml and a CD4+ count of |[ge]|150. Additionally, subjects must have a Karnofsky Performance score of 80 or higher, have no evidence of active opportunistic infection, congestive heart failure, hemodynamic instability, bleeding diathesis and no contraindications for leukapheresis. Patients will receive repeated doses by i.v. of |[sim]|1|[ast]|1010 genetically modified autologous T-cells, every two weeks. The primary safety objectives will include incidence of adverse events, changes in viral load, changes in CD4+ T cells, changes in TCR v beta repertoire, and tests for replication competent lentivirus (RCL). Tissue trafficking of gene modified cells will also be monitored in GALT tissue. The first part of the study is evaluating the safety and tolerability of multiple dosing using a repeat dosing design. All patients in the 4 dose cohort have received their infusions as scheduled and have reached the 3 month post-infusion visit, and one patient in the 8 dose cohort has received all of the doses as scheduled. To date, all of the doses have been well tolerated and preliminary results suggest multiple infusions are safe, with no SAE's due to the product, no changes in hematology or chemistry laboratory evaluations, and no detection of VSVG DNA or RCL. In the second part, we are determining an optimal dosing regimen for future confirmatory trials. To date 18 patients have been enrolled and 11 have started receiving infusions. The data generated from the current clinical trial demonstrates the clinical utility of lentiviral vector technology as an alternative for treatment of HIV infection.