Tamiflu is no better than a placebo, researchers say

Rona Ambrose says feds reviewed trials before stockpiling over $100 million worth of a drug doctors say does not save lives


The minister of health said the government reviewed drug trials for Tamiflu, a flu prophylaxis recently found to be ineffective by the Cochrane Collaboration, before releasing it for public consumption.

After touring St. Joseph’s Health Centre on April 10 as “Resident for a Day,” Minister Rona Ambrose responded to NOW’s question asking if the government undertakes reviews of clinical trials before releasing drugs, specifically Tamiflu, to the public.

“Of course [we do],” said Ambrose.

Meanwhile the Cochrane Collaboration, an international group of academics producing hundreds of systematic reviews on medicine, was locked in a years-long legal battle with the drug’s maker, Roche, over access to trials. Cochrane released their review of the pharmaceutical company’s trials Wednesday saying there is no good evidence that Tamiflu saves lives.

After its release, Dr. Peter Doshi, co-author of the report, told NOW, “The reason [Tamiflu and Relenza were] stockpiled is because they interrupt the transmission the of virus and reduce the amount of people who would be hospitalized or die from the flu. There’s no good evidence that the drugs have these effects.”

Doshi, a pharmacy professor with the University of Maryland and his 11 co-authors reviewed randomized, placebo-controlled trials from the drug’s manufacturers. Those trials included more than 24,000 adults and children and data from the UK, U.S., Europe and Japan.

According to the U.K.-funded report, Cochrane reviewed over a hundred trials to determine the drugs’ benefits are “essentially what you get out of fever-reducing medicines like Aspirin and Tylenol,” Doshi said.

Dr. Barbara Mintzes from the Department of Anesthesiology, Pharmacology and Therapeutics at the University of British Columbia has questioned the efficacy of the drug noting that its value has been overstated from the beginning.

“This is the first time that the full clinical trial data has been available in order to carry out a full systematic review,” said Mintzes.

“It really raises questions about the decision to stockpile Tamiflu,” she said. “Because of the very modest effectiveness on flu symptoms and the lack of evidence from the randomized control trials that it reduces complications and hospitalization.”

Mintzes became interested while evaluating drugs for the Therapeutics Initiative for the BC ministry of health. She reviewed both Tamiflu (Oseltamivir) and Relenza (Zanamivir) when they first came to the market in the early 2000s.

“At that point there wasn’t any evidence of effect on complications of the flu – what you would want from a flu drug,” she said.

For both Tamiflu and Relenza, she said, there is “no difference between the drug and a placebo.”

Despite the findings of the Advisory Board for the U.S. Food and Drug Administration that the two drugs were not effective, the Centre for Disease Control and Health Canada approved both drugs for release to the public.

Mintzes explained that the government does review pharmaceuticals before they’re released to the market, but that the studies they review are biased and the methodologies are flawed because the trials are conducted by the drug’s manufacturers.

“Often drugs are approved based on really inadequate evidence,” she said.

The problem as she sees it is with research and publication bias. If the manufacturer is responsible for carrying out the studies and those studies are confidential, it’s in the companies interest to choose what information to release.

“They’re not always publishing complete information,” she said, and their methods are flawed. This has been at issue with the Cochrane Collaboration’s attempts to see both Roche’s and GlaxoSmithKline’s trial information for Tamiflu and Relenza respectively.

“The methods the Cochrane reviewers have used are excellent,” she said. “What they’ve done is that they’ve combined all of the evidence from all of the experimental studies that were done of these flu drugs.”

Arthur Schafer, Director of the Centre for Professional and Applied Ethics at the University of Manitoba, says there was “no evidence that these drugs were efficacious.”

“It’s an absolute scandal,” he said.

As of 2011, the federal and provincial government had stockpiled $180-million worth of anti-virals, mostly Tamiflu.

Sylwia Krzyszton from the PHAC replied by email to NOW’s questions seeking clarity about the reviews.

“The Public Health Agency of Canada closely monitors the scientific literature related to the effectiveness of antivirals for the prevention and treatment of influenza, and the balance of evidence supports their use,” wrote Krzyszton.

More to come.

cynthiam@nowtoronto.com | @cynthiajmcqueen

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