Questions raised over unpublished Tamiflu data

We've written before about pharmaceutical companies not releasing all the data from their trials. Previously, we've written about how this can mean delays in identifying potential dangers from drugs. This time, it's about whether they work as well as their manufacturers claim.

This week, British researchers questioned research into the benefits of the antiviral drug Tamiflu (generic name oseltamivir), widely used around the world since the outbreak of the swine flu pandemic, because the full results of studies have not been published.

The researchers, from the internationally-respected Cochrane Collaboration looked again at previous studies that had concluded Tamiflu could prevent complications such as pneumonia in people who got seasonal flu. Avoiding complications is one of the main reasons for taking the drug, although it can also cut the amount of time you have symptoms by about a day.

The Cochrane researchers rejected some of the key research into complications, saying that they couldn't verify the results as they were not able to view all the data. The problem was that eight of the trials of the drug (carried out for the manufacturer Roche) had not been published. Instead, previous researchers had relied on a published summary of the trials, which was also written for Roche. The Cochrane researchers contacted Roche, but were unable to see all the unpublished research on which the summary was based.

As a result, the Cochrane researchers said there is not enough data that can be independently checked, to say whether or not Tamiflu can prevent complications. The results leave governments and patients in limbo. Is it worth taking the drug (which can cause unpleasant side effects for some people) to cut your risk of complications, when we can't see the data about this? 

Roche has responded by saying it will release the full results to scientific researchers, although it hasn't made any pledge to make them available to the general public. Isn't it about time all pharmaceutical companies made their trial results fully available to everyone? Openness may be the only way to restore trust.

What you need to know. Tamiflu may cut your chances of complications from swine flu, or it may not. Until we can see all the data from all the trials of this drug, we simply can't say.

—Anna Sayburn, patient editor, BMJ Group

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