jueves, 10 de enero de 2013

TAMIFLU: 5 verdades...y una noticia.




1. The manufacturer of the drug sponsored all the trials and the reviewers found evidence of publication and reporting biases. With so much at stake I was surprised that there had been no prospective, placebo-controlled trials conducted that were funded by an independent source. Industry trials can be well conducted, but there are many situations where a lack of independence has had an influence on the way the study was designed and the results that are released. At the very least, it is worth noting that they were probably designed to have the best chance of showing benefit. And that the reviewers had concerned about whether all the information was released. In addition the experts found evidence of reporting bias. According to Tom Jefferson, one of the authors of the Cochrane study: 60% of randomized data from the Tamiflu treatment trials (i.e. in people with influenza-like-illness symptoms) have never been published including the biggest trial ever conducted (which was done in the US, so it’s of great relevance to you).”

2. The studies did not show that Tamiflu reduced the risk of hospitalization. One of the reasons people might take an antiviral is to prevent the illness progressing to the point where they would need to be hospitalized. Unfortunately there was no evidence that the drug produced that benefit.

3. The studies were inadequate to determine the effect of Tamiflu on complications. Even though the drug did not reduce hospitalizations, some people may think it would prevent less severe complications. Unfortunately, the reviewers found that limitations in the design of the trials, their conduct, and the way they were reported precluded any conclusions about the effect of the drug on complications. To expect that Tamiflu can reduce complications would be a leap of faith currently unsupported by the available evidence. You should also know that the FDA requires Roche to print on the label: “Tamiflu has not been shown to prevent such complications [serious bacterial infections].”

4. The studies were inadequate to determine if Tamiflu reduced transmission of the virus. Same story. Some people might prescribe the drug to prevent the spread of the virus. The expert reviewers simply said that with what information they had available; they could not assess the effect of the drug on transmission. I asked Peter Doshi, one of the authors of the Cochrane report about this issue of transmission and here is what he wrote me: “Roche’s prophylaxis trials were not designed to answer the question of transmission. The prophylaxis trials – and FDA approval of Tamiflu for prophylaxis – is based on its proven ability to reduce the chances of symptomatic influenza. (But since we don’t know anything about asymptomatic influenza infections, we cannot say anything about whether or not Tamiflu reduces actual transmission of virus.)”

5. The use of Tamiflu did reduce the duration of symptoms by about a day. The reviewers found 5 studies that assessed the effect of Tamiflu on the duration of symptoms. They were fairly consistent in their findings – though the duration of the symptoms varied quite a lot across the studies. (Más)

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Ver también:

BMJ editor urges Roche to fulfil promise to release Tamiflu trial data. 

Roche esconde.../podría no curar sino matar
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