Be specific. nonspecific HIV microbicides - applied as a gel using this device - do not go to work, researchers say.
NIAID
The largest ever study of a microbicide to prevent infection with HIV resulted in another case high hopes dashed on promising product. Earlier this year, a smaller study by the same vaginal gel gave a hint that he may offer modest protection, but the new results put the question to rest. "It will not work," says clinical epidemiologist Sheena McCormack, who led the study in four countries for the Unit Medical Research Council UK on clinical trials.
McCormack said data mark the end of the road not only for vaginal gel, but the whole class of microbicides that use non-specific compounds to prevent HIV infection. the placebo-controlled trial in approximately 9500 women tested a gel called PRO 00 a so-called polyanion that has prevented the AIDS virus from entering human cells in the laboratory and monkey studies. the four-year study of $ 44 million over six sites in sub-Saharan Africa has found no difference between the treatment and placebo groups of equal size of the study: There were 130 HIV infections in women who used PRO 00 and 123 in those who used a dummy gel
. researchers in the field of HIV prevention beleaguered often see glimmers of hope in even the discouraging results of clinical trials - witness the vaccine against AIDS study recently completed in Thailand. But this is not the case with these conclusions. "The first time I looked at the data as a statistician I said, 'You're not going to need more analysis, are you?" Said Mr. McCormack, who is based in London. " it is really clear. "
in February, a similar study of PRO 00, which only covered about a third that many women found 30% fewer HIV infections in the treated group, but with a value p 0.10. - a positive trend that did not reach statistical significance in this study $ 0 million, funded by the US National Institutes of Health (NIH), surprised many in the area which, on the basis of other failures of nonspecific microbicides, predicted the product would not do anything. But McCormack noted that the new findings are actually consistent with test data earlier, which had a wide confidence interval and included the possibility that the product not working
McCormack said there is an increase of failure .: it informs future clinical trials. Because the results clearly show that positive test tube studies and the monkey PRO 00 are misleading, researchers now know how to use more stringent requirements for judging a product worthy of human trials.
The microbicide field has now been several effectiveness studies have failed with both polyanions and another class of non-specific compounds called surfactants. Trials are underway with several products that specifically target HIV. Sharon Hillier and Ian McGowan of the Microbicide Trials Network US, which ran the study funded by the NIH of PRO 00 in a statement released today that the new findings "raise little doubt that at this stage, the agents who specific action against HIV, including antiretroviral medicines, offer the most hope. "
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