'No confidence' in claim Tamiflu prevents complications

The first study in 2006 suggested it. The 2009 update suggests the same thing. There is no clear evidence that anti-flu drug Tamiflu prevents complications - a finding that undermines the government-s main reason for spending £500 million on the drug in the battle against swine flu.

An expert review is published by the BMJ today, which updates a 2006 review published in The Cochrane Library. It acknowledges that oseltamivir (brand name: tamiflu) and other neuraminidase inhibitors have a modest effect in reducing flu symptoms and infectivity in otherwise healthy adults by about one day.

But the researchers say that there is insufficient published data to know if oseltamivir reduces further complications such as pneumonia in otherwise healthy adults. It was the drug's role in the prevention of complications that prompted the government to stockpile it.

The study has led to an inquiry by Channel 4 News.

Dr Fiona Godlee, editor in chief of the BMJ, warns that this updated review leaves important questions about effectiveness unresolved. ‘Governments around the world have spent billions of pounds on a drug that the scientific community now finds itself unable to judge,’ she says.

The use of neuraminidase inhibitors, especially Tamiflu, has increased dramatically since the spread of the influenza A/H1N1 (swine flu) pandemic began in April 2009. In the absence of an effective vaccine and because of resistance to previous drugs used against flu, neuraminidase inhibitors were seen as the answer to the pandemic.

Eight trials unverifiable

Roche, which produces Tamiflu, has estimated sales of £1.6billion this year alone from the drug. But its claimed trial results have been difficult to independently verify.

The research team, led by Professor Chris Del Mar from Bond University in Australia, analysed 20 published trials that focused on prevention, treatment and adverse reactions.

But their investigation was hampered by the 'paucity of good data' available from authors and Roche. Hence the team dropped eight key trials which were never fully published that were included in the earlier review because they were unable to independently verify the results. As a result, they conclude that they have no confidence in claims that Tamiflu reduces the risk of complications of influenza in otherwise healthy adults, and believe it should not be used in routine control of seasonal influenza.

Roche promises to publish data

Roche said that they 'firmly believe in the robustness of the data'. They point out that full access to data has been granted to Governments and regulatory authorities.

As a result of the BMJ/Channel Four News investigation, Roche has committed to make all study summaries of Tamiflu including key data available on a password-protected site.