(Reuters Health) - HIV-specific immunization may enhance antiretroviral therapy, according to a report in the December 15th issue of The Journal of Infectious Diseases.
"Even with a relatively weak immunogen, there is statistical evidence to demonstrate an improvement in host immune control," Dr. J. Michael Kilby from the University of Alabama at Birmingham told Reuters Health.
Dr. Kilby and colleagues in the Adult AIDS Clinical Trials Group A5024 Protocol team investigated whether immune-based strategies incorporating the ALVAC vCP1452 vaccine would improve host immune control after antiretroviral therapy interruption. [p. 1672, col. 2, para. 2]
There was a trend toward lower viral rebound in patients who received the vaccine, the authors report, with a significantly greater percentage of vaccine recipients (31%) maintaining viral loads below 5000 copies/mL beyond 12 weeks of therapy interruption, compared with placebo recipients (9%).
The addition of interleukin (IL)-2 did not influence viral rebound, the results indicate, but IL-2 recipients experienced significantly greater CD4+ T cell count increases than did patients who did not receive IL-2.
HIV-specific lymphoproliferative immune response did not change significantly in any treatment group, the researchers note.
Among patients treated with IL-2, grade 3 or 4 adverse events were more common among those given vaccine plus IL-2 (74% of patients) than among those given placebo plus IL-2 (30%), the report indicates.
After resumption of antiretroviral therapy, all patients had prompt resuppression, the investigators say.
"As better and better immmunogens become available for testing we should consider this approach (comparing viral load 'rebound characteristics' 12 weeks after interrupting therapy) to evaluate their potential application as therapeutic immunizations," Dr. Kilby said.
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