Background: The PEDVAC study is the first trial to analyze the feasibility of a therapeutic vaccination strategy with a DNA-HIV vaccine (HIVIS) in infected children.
Materials & Methods: The HIVIS is a combination of seven plasmid DNA constructs, intramuscularly delivered. Twenty vertically HIV-1 infected children under HAART(4-16 years of age) on stable viral control for at least 6 months and CD4-value above 400 cells/mm3/25% over 12 months of follow-up, were recruited. Immunizations took place at week 0, 4, 12 and 36.
Results: Cellular immune reactivities to full MN viral antigens, to recombinant gag p24 and to purified RT were monitored by lymphocyte proliferation assays and intracellular staining. At week 16, strong responses to the HIV MN antigen were observed in the vaccinees compared to the control groups-stimulation Index (SI) level over 15 (p 0.087). The total highly elevated SI values to p24 and RT for week 12-96 were higher in the vaccinated compared to the non-vaccinated group (p 0.058,p 0.007 respectively). At visit 16 and 60 the frequency of HIV-specific CD8+ lymphocytes releasing perforin (>0.200%) was higher in vaccinated than non-vaccinated children (p 0.030). Safety data showed good tolerance to the vaccinations. None had a decrease in CD4+ lymphocyte cell counts from baseline. Two children experienced a single viral blip (all four not exceeding 1000 HIV-RNA copies/ml). No significant differences between the two arms were observed in ultrasensitive HIV-RNA viral load at week 16 and 40, and HIV-DNA at week 0, 48 and 108. Conclusions: This first attempt to study therapeutic HIV-DNA immunizations in perinatally HIV-infected children showed that the tested regime was feasible and safe.
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