Tamiflu Safety, Benefits and Effectiveness Uncertain

More research needed on Tamiflu
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It’s the middle of flu season, and many people are turning to Tamiflu® to help them reduce the severity of symptoms and the possibility of developing complications associated with influenza. Yet years after Tamiflu hit the market, the safety and benefits of the drug are uncertain, and investigators say the drug’s maker Roche has refused to release full data on the product.

Is Tamiflu safe or effective?

Two years ago, Roche promised the British Medical Journal it would release key trial data concerning Tamiflu (oseltamivir) so it could undergo independent evaluation. Yet the information has not been provided to the Journal, and the Cochrane Collaboration has also reported that Roche has refused to provide it with complete access to data so it can fully evaluate the drug.

According to the Tamiflu website, the antiviral medication is for the treatment of uncomplicated flu caused by viruses types A and B in individuals who are 12 months of age or older who have not had flu symptoms for more than two days. Tamiflu may also be used to help prevent flu in the same age group.

But does Tamiflu work, and it is safe?

In the British Medical Journal’s new report, the author expressed serious concerns about Roche’s use of ghost writers in the clinical trials and how the drug approval process was conducted, including how different regulators used different approaches to the data given to them, which in turn resulted in conflicting reports about the drug’s effectiveness.

The Cochrane researchers, who have attempted to test whether Tamiflu can really prevent complications of flu and reduce the number of people who need hospitalization as Roche claims, have also been unsuccessful in getting the promised data from the drug maker.

Cochrane investigators were promised access to full study reports after they issued their report on Tamiflu in 2009 and “we concluded that the published evidence did not support the effectiveness of oseltamivir in reducing the complications of influenza such as pneumonia.”

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The promised complete reports were not provided. When the Cochrane team was given some clinical study reports by the European Medicines Agency, they uncovered inconsistencies and possible under-reporting of the drug’s side effects.

In the past few years, Tamiflu has become a commonly prescribed medication for the flu, and was even added to the World Health Organization’s list of Essential Medicines.

Yet, as the new British Medical Journal report noted, “how has this happened to a drug whose effectiveness is not backed up by publicly available evidence and whose manufacturer has broken successive pledges to make full study reports available?”

In the United States, uncertainty about Tamiflu continues. On the one hand, the Food and Drug Administration (FDA) elected not to review the largest trial of Tamiflu ever conducted when it considered the drug for approval, and noted that the drug had not been shown to prevent complications.

On the other hand, the Centers for Disease Control and Prevention (CDC) states that Tamiflu reduces the risk of flu complications.
According to Dr. Fiona Godlee, editor-in-chief of the British Medical Journal, “The discrepancies between the conclusions reached by different regulators around the world highlights the absurd situation we find ourselves in.”

That absurdity involves making decisions about people’s health and well-being, and Godlee urged regulators to cooperate on the Tamiflu issue. “Otherwise we will continue to waste money and risk people’s health on drugs that don’t work.”

SOURCES:
Cohen D. Search for evidence goes on. BMJ 2012; 344:e458
Doshi P, Jones M, Jefferson T. Rethinking credible evidence synthesis. BMJ 2012; 344:d7898
Tamiflu website (Genentech, USA)

Picture credit: National Institutes of Health

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