Researchers Questions Tamiflu's Effectiveness
Scientists now question how well the popular drug cuts flu severity.
Dec. 8, 2009— -- There's not enough evidence to conclude that the antiviral drug oseltamivir (Tamiflu) has any benefit for the complications of influenza in otherwise healthy patients.
That's the straightforward conclusion of an updated Cochrane review of the drug, appearing online in the British Medical Journal -- and many experts say it's not surprising.
"The currently available antiviral medications for treating influenza in otherwise healthy adults have never been shown to have much impact," said Dr. Richard Besser, ABC News senior health and medical editor.
But the path that led to that conclusion is anything but clear-cut, according to the journal's editors.
In a series of articles, including the review, the journal says that what began as a "straightforward exercise to confirm the evidence base for current policy and practice became instead a complex investigation."
The journal's editors raised a series of issues aside from the narrow clinical question, including who had access to data from Roche-funded trials, whether ghost writers were used to prepare journal manuscripts, and why some authors were not listed while -- in at least one case -- an author was cited who later said he can't recall performing the study.
A key concern was a meta-analysis of 10 studies that formed part of an earlier review -- a report whose conclusions could not be validated, in part because the drug's manufacturer, Roche, was slow in releasing the raw data, according to Fiona Godlee, the journal's editor.
"This is a long way from being the only time in which Roche and other drug companies have declined to share necessary data with legitimate authorities," Godlee said in an email.
The Cochrane group reviewed the evidence on antiflu drugs and concluded in early 2006 that -- among other things -- oseltamivir was effective in reducing the complications of flu among healthy adults.
At 150 milligrams a day, oseltamivir was effective in preventing lower respiratory tract complications in influenza cases, with an odds ratio of 0.32, the reviewers, led by Tom Jefferson, concluded at the time.
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