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A Randomized, Controlled, Phase II Study with an MVA-nef Vaccine in HIV-1 Infected Patients Followed by Structured Treatment Interruption (STI)
Thomas Harrer, Germany
 - Biography
English - 2007-10-26
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Abstract
Objective: MVA-BN, a viral vector which is safe and fails to replicate in human cells, has shown potent ability to induce cell mediated immune response in previous phase I/II studies. This phase II trial was initiated to assess the immunogenicity and safety of the MVA vector expressing HIV-1-LAI nef in a HIV-1 infected population on stable HAART with CD4 counts > 250/µl.
Methods: In this single blind, controlled, randomized, multicenter phase-II-trial 77 HIV-1 infected patients received three s.c. vaccinations of either 1E8 MVA-BN, 1E8 MVA-nef or 5E8 MVA-nef (n=25, 26 and 26) at week 0, 8 and 16. 60/77 subjects were preimmune to vaccinia due to prior smallpox vaccination. Patients that had received all vaccinations and remained stable on HAART with HIV-1-RNA levels < 50 copies/ml were offered a Structured Treatment Interruption (STI) at week 20 and were followed up until week 52.
Results: MVA-nef proved to be safe and well tolerated. All 77 subjects received three vaccinations. 37 subjects interrupted HAART 4 weeks following the third vaccination (9:13:15 for 1E8 MVA-BN, 1E8 MVA-nef, 5E8 MVA-nef,respectively). During the 32 week post STI period 12 of 37 subjects restarted antiretroviral therapy, mostly due to increasing VL; these patients came back to contolled VL after re-start of HAART. Data collected from the 25 patients followed up until week 52 indicate a significant better control of the VL in the group vaccinated with 5E8 MVA-nef compared to the MVA-BN vaccinated control group. All patients developed a strong MVA-specific humoral immune response. Data on Nef specific cellular immune responses are currently analysed and will be available soon.
Conclusions: The results of this study confirm the promising data of a previous Phase I trial which indicated a trend in controlling VL during STI after therapeutic immunisation with MVA-nef (Harrer et al. Antivir Ther 2005).
Bibliographic references
Harrer T., Hain J., Meyer T., Baedecker N., Sobek V., Baeuerle M., Jaeger H., Helm M., Schneider L., Gorriahn D., Harrer E.G., German Competence Network on HIV/AIDS. "A randomized, controlled, phase II study with an MVA-nef vaccine in HIV-1 infected patients followed by Structured Treatment Interruption (STI)"
