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Flu epidemic renews hype — and serious questions — about Tamiflu

REUTERS/Andrew Kelly
Scientists have raised serious questions about the claimed effectiveness of Tamiflu.

As this year’s nasty influenza season reaches what may be its peak, the demand for Tamiflu (oseltamivir), the prescription antiviral drug that’s supposed to reduce the duration of the illness and its complications, has skyrocketed. In fact, shortages of the drug, particularly of the liquid form used to treat children, have been reported in some areas of the country.

That demand is good news, of course, for the drug’s maker and marketer, the pharmaceutical giant Roche. According to a Morningstar analyst, sales of Tamiflu will double this year to $750 million.

But, as I’ve reported here before, some scientists have raised serious questions about the claimed effectiveness of Tamiflu. In 2009, the independent and highly respected Cochrane Collaboration reported that the data on Tamiflu was insufficient to determine that the drug reduces flu-related complications. The drug may reduce flu symptoms modestly in otherwise healthy people, the Cochrane researchers said, but there was no good evidence that it reduced the rate of flu-related hospitalizations and deaths — the endpoints that truly count and the main reason the drug is prescribed by physicians.

The Cochrane group updated that report early in 2012, noting that it had found “a high risk of publication and reporting biases” in the studies involving Tamiflu.

It called (again) on Roche to release all its “full study reports” (internal data) on the drug so that independent researchers could evaluate it. The company has repeatedly resisted that request. (The journal BMJ has joined Cochrane in its push to get Roche to release the data, and has established a dedicated web page for the campaign.)

What consumers need to know

As Dr. Harlan Krumholz, a professor of investigative medicine and public health at the Yale University School of Medicine, noted in an article published online last week in Forbes, there are five things health consumers need to know about Tamiflu:

1. The manufacturer of the drug sponsored all the trials and the [Cochrane] reviewers found evidence of publication and reporting biases. … [In fact,] 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.

2. The studies did not show that Tamiflu reduced the risk of hospitalization.

3. The studies were inadequate to determine the effect of Tamiflu on complications. … [In fact,] 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.

5. The use of Tamiflu did reduce the duration of symptoms by about a day … though the duration of the symptoms varied quite a lot across the studies.

“There remains substantial uncertainty about whether this drug is worth taking,” concludes Krumholz. “Meanwhile, it is worth asking — why [is Roche] unwilling to share the information they have? And should doctors keep prescribing medicines when some potentially vital information is being kept out of view?

You can read Krumholz’s article on the Forbes website.

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