Monday, June 20, 2011

Tenofovir Gel Still Hyped, Despite Serious Questions About Trial

The rather disappointing 39% reduction in HIV infection among women who received tenofovir microbicide gel during the clinical trials has since been written about as if it is going to turn the epidemic around. It might, but the reduction would need to be a lot higher than 39%. A lot of questions will also need to be answered about the way the CAPRISA 004 trial was run and reported on.

But immediate efforts have been made to 'fast-track' approval so that the gel can be produced commercially. A site has already been identified for the factory, which makes it sound as if the many further trials that are needed to establish if the gel is going to have any impact at all on the HIV pandemic are irrelevant.

Any drug that is overused carries the risk of widespread resistance. This is something pharmaceutical companies are acutely aware of, given the substantial increase in their profits when people need to change to a newer and inevitably more expensive drug as a result of resistance. But if millions, perhaps tens of millions, eventually use this gel, levels of resistance could go far beyond what could be controlled (whatever level that might be).

And an important question, apparently, is that the reasons behind the HIV transmissions during the trial, and therefore the effectiveness of the Tenofovir drug, are not yet clear. One researcher has suggested that anti-inflammatories may be useful in reducing HIV transmission.

Another question that has been raised about effectiveness is that it is possible the gel only protected women if the viral load in their partner's semen was high. The trial results made public were a bit vague about exactly what risks were faced by the women who became infected, and if all of them were really infected sexually. Perhaps the less flattering results of the trial will be made public now?


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