Researchers who gained access to eight unpublished studies of oseltamvir (Tamiflu) say the data show the drug has less benefit on symptoms and does not reduce rates of hospitalisation.
Writing in Family Practice, researchers from the University of Georgia say they found an additional eight randomised controlled trials (RCTs) of the drug that had not been published by the manufacturer, Roche.
When the data from these studies were analysed in addition to the three published trials, the average reduction in flu symptoms was only 21 hours based on an intention-to-treat basis, rather than the published estimates of 30 hours. Two unpublished studies found no effect on symptoms duration in the elderly and chronically ill patients.
Their analysis also showed that Tamiflu did not reduce hospitalisation or risk of pneumonia. There was also no significant effect on complications when the researchers excluded acute bronchitis, which they said was not a complication that needed an antibiotic according to best evidence.
The researchers say they were concerned “about the failure to publish the results of large adequately-powered RCTs in peer reviewed journals.”
“Physicians widely believe that oseltamivir prevents hospitalisations and complications, particularly in more vulnerable patients such as the elderly and patients with chronic cardiac or respiratory co-morbidities. However, we found no evidence that oseltamivir reduces the likelihood of either of these important clinical outcomes,” they say.
Cochrane reviewer Professor Chris Del Mar of Bond University recently described his “frustrating” three-year battle for access to data on Tamiflu and called for all data to be made public.
And the findings come as the renowned Bad Science author Ben Goldacre highlights the implications of unpublished pharmaceutical trials in his new book Bad Pharma released this month.
In his book, Dr Goldacre cites the example of negative trial data for the antidepressant reboxetine which was not published by GSK. He says the unpublished data showed that patients on reboxetine did worse than those on other drugs, and that patients were more likely to have side-effects, more likely to drop out of taking the drug and more likely to withdraw from the trial because of side-effects, if they were taking reboxetine rather than one of its competitors.
"Missing data poisons the well for everybody. If proper trials are never done, if trials with negative results are withheld, then we simply cannot know the true effects of the treatments we use. Evidence in medicine is not an abstract academic preoccupation. When we are fed bad data, we make the wrong decisions, inflicting unnecessary pain and suffering, and death, on people just like us," he writes in the Guardian.
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