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Previous immunity to adenovirus 5 (Ad5), a common cold virus, may explain why volunteers receiving Merck’s preventive HIV vaccine may have been more likely to become infected with HIV than those receiving placebo injections, suggest researchers associated with the international STEP study. The new information was reported yesterday at a special gathering of HIV Vaccine Trials Network (HVTN) researchers and community advocates in Seattle.
Ad5 was used in the vaccine being developed by Merck and studied by HVTN. The shell of the virus was used as a vector to deliver pieces of HIV’s genetic material to immune system cells.
According to researchers at the meeting in Seattle, 49 male participants who received the vaccine became infected with HIV, compared with 33 males who received the placebo. There was only one infection among female participants, so they were not included in the post-study analysis. The difference in infections among the men was particularly striking when they looked at participants whose immune systems were strongly reactive to the Ad5 vector: 21 of those vaccine recipients became infected with HIV compared with just 9 who received a placebo.
The researchers cautioned that the numbers are so small and the data so new, that it is way too early to tell whether this trend toward greater HIV susceptibility in the vaccine recipients is real, or merely coincidence. They promised to continue analyzing the data with speed and intensity in hopes of answering this question as soon as possible.
The anti-herpes drug Valtrex (valacyclovir) has been found to lower HIV viral load in the blood and genital secretions of men with underlyingherpes simplex vius-2 (HSV-2) infection, according to a report on a study from AIDSmap. The study confirms earlier research and further suggests that herpes treatment, in the absence of HIV therapy, may have health benefits and help prevent ongoing transmission of HIV.
Richard Zuckerman, MD, MPH, of the section of infectious disease and international health at the Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire, and his colleagues studied valacyclovir treatment in 20 men infected with both HIV and HSV-2 in Lima, Peru. The men were randomized to receive either 500mg of valacyclovir twice a day or a placebo for eight weeks. Then after a two-week pause, the dosing groups were switched so that those who’d received placebo now received valacyclovir and those who’d received valacyclovir now received placebo for an additional eight weeks.
Treatment with valcyclovir was associated with a 31 percent decrease in HIV viral load from rectal samples compared with placebo, and a 53 percent decrease in HIV in the blood. The study’s authors conclude that suppressing HSV-2 production in people coinfected with HIV results in significant reductions in both HSV-2 and HIV.
The Food and Drug Administration has approved a new low-dose Kaletra (lopinavir/ritonavir) tablet, sold as Aluvia in many other parts of the world, for use in HIV-positive children, according to the drug’s maker, Abbott.
As reported at the 11th European AIDS Conference in Madrid in October, Abbott has demonstrated that the new Kaletra tablets produce blood levels equivalent to the standard adult dose Kaletra. Abbott has also worked out dosing recommendations appropriate for children regardless of age or body size.
For children who can swallow pills, the new tablets can be used in place of the liquid formulation of Kaletra, which contains alcohol and, according to many HIV-positive children, has a bad taste. The new tablet formulation is also expected to have fewer digestive side effects like nausea and diarrhea.
The new tablets, containing 100mg lopinavir and 25mg ritonavir, will be available in the United States this month. Abbott is awaiting approval for the lower-strength tablets in Europe and to register the new formulation in more than 150 countries.