AIDS vaccine does not allow a better viral control if nterruption an anti-retroviral treatment

The strategy of treatment with combination therapy (ART) to a vaccine does not allow a better viral control that ART only during treatment interruption, when the ART was initiated in the acute phase, shows the International Study Quest.

Vaccination, treatment and HIV ...

The vaccines used in this study are a modified canarypox virus and recombined with genes encoding different regions of HIV (vaccine) and an inactivated HIV-1 virus lacking the envelope gene vaccine (b).

The study was double-blind and included 79 patients were randomized into three groups. Group A was treated with ART alone and placebo both vaccines, group B ART, the vaccine "a" and placebo vaccine "b" and C ART group, and two vaccines.

The vaccine "a" was used to increase preferentially cytotoxic T lymphocytes (CTL), while the "b" was used to increase the CD4.

All patients were treated with ART during primary HIV infection and followed this treatment for more than 72 weeks. Their viral load was less than 50 RNA copies / ml four weeks before randomization.

After 20 weeks of immunization in the acute phase, and an additional four weeks of ART, patients discontinued all treatment.

No difference in viral load between the groups at six months

After six months of interruption, 17.7% of patients had a viral load less than 1,000 RNA copies / ml, and this proportion did not differ between the study arms.

Vaccines have not resulted in better viral control during the interruption. Yet they are immunogenic. The number of CD4 T cells and had a tendency to increase during the phase of immunization in patients vaccinated groups compared to the placebo arm.

The level of immunogenicity before interruption of therapy is not correlated with viral load six months.

"Our study was not able to demonstrate a link between the level of response of T cells specific for HIV-1 viremia," commented Dr. Sabine Kinloch-de Loes, first author of the study and colleagues.

"This underscores the importance of evaluating both immunological and virological effects in vaccine trials," say Tim Rajesh Gandhi and Marcus Altfeld of Harvard Medical School in Boston in an editorial accompanying the article.

In fact, six-month break, there was no difference between the three arms of the study, in terms of viral load or CD4 and CD8.

No severe adverse effects

Adverse effects of treatment were observed in all three groups, affecting 33% of group A, group B 54% and 69% of group C, characterized by reactions at the injection site, musculoskeletal pain and fatigue. There were no severe effect leading to discontinuation of treatment.

"The interruption of ART seems sure," the editorialists comment, "even if the decrease in average CD4 after interruption is 139 cells/mm3, no patients progressed to AIDS stage or has reached a CD4 count below 200 cells/mm3. " This, no doubt due to the high rate of CD4 at baseline (greater than 700 cells/mm3), they said.

Monitoring the cohort Quest determine virological, immunological and clinical effects in the longer term vaccination strategy, announced the authors.

They point out that these results do not automatically apply to patients chronically infected..