Tamiflu: serious questions remain
Posted by medconsumers on January 23, 2010
We recently reported that Tamiflu lowers a healthy person’s chances of getting the flu by 4 percentage points (see How good is Tamiflu?). Now a cloud doubt hovers over this drug’s safety and its vaunted ability to prevent severe complications, according to a newly updated Cochrane review published last month in the BMJ (British Medical Journal). Tamiflu was approved by the FDA to shorten the duration of seasonal flu by about one day and to prevent the seasonal flu in healthy adults and children. Soon after the H1N1 influenza outbreak of April 2009, Tamiflu morphed into a drug that is also good at preventing swine flu, though no studies had provided proof. [Note: Tamiflu is named throughtout this article because it is the best known drug in a class called neuraminidase inhibitors, which also includes Relenza. The findings from this newly updated Cochrane review apply to both drugs.]
What takes the Tamiflu story beyond the usual expensive-drug hype is the fact that it is an international public health story. Countries around the world, including our own, began to stockpile Tamiflu several years ago, spending billions annually. Roche, the company that makes Tamiflu, “bought” the World Health Organization’s brand loyalty in much the same way drug companies encourage doctors to prescribe expensive drugs with free samples. In a 2005 press release, the World Health Organization “welcomes Roche’s donation of three million treatment courses of its antiviral oseltamivir [Tamiflu] to a WHO international antiviral stockpile.” At the time, Tamiflu was regarded as the drug for avian (bird) flu, though no studies had provided proof. Central to the widespread confidence in Tamiflu was the claim that it lowers the risk of serious flu-related complications like pneumonia.
That claim and reports of Tamiflu’s severe adverse reactions became the impetus for the newly updated Cochrane review led by Dr. Tom Jefferson. In a nutshell, here’s what the authors found: the original studies that showed benefits to Tamiflu are now suspect where it concerns influenza complications and adverse reactions to the drug itself. About half of the studies were never published and are therefore unavailable for the in-depth analysis that is the hallmark of a review from the Cochrane Collaboration. All were sponsored by Roche, maker of Tamiflu, and most troubling, no independent studies of Tamiflu have ever been conducted. The hard-hitting editorial that accompanied this Cochrane review observed that the new findings have broad implications because they cast “doubt not only on the effectiveness and the safety of Tamiflu but on the system by which drugs are evaluated, regulated, and promoted.”
The review seems to confirm Tamiflu’s ability to shorten the duration of the seasonal flu by one day, if taken within 48 hours of first symptoms. However, the crucial question about the drug’s purported ability to reduce influenza-related complications like pneumonia could not be answered because of the unavailable data from the Roche-sponsored studies. And for the same reason, Jefferson and colleagues were not able to determine whether the reports of Tamiflu-related deaths and neuropsychiatric reactions, such as hallucinations and delirium, are actually rare occurrences. Nausea, vomiting, and retching are acknowledged to be common side effects of Tamiflu.
In a telephone interview, Dr. Jefferson, who is an internationally recognized influenza expert, took full responsibility for his role in advancing the Tamiflu hype. He was the lead author of the 2005 Cochrane review that lent credence to Tamiflu’s efficacy in preventing and treating the symptoms and complications of influenza. “We made a mistake in 2005,” he admits, “We took the data from the Roche-sponsored meta-analysis [of ten Tamiflu studies] on trust without checking the sources of the data. Had we done that, we would have realized that eight of ten studies were unpublished. And in over half of these studies, everyone except the lead author was either a Roche employee or a [Roche-paid] consultant. This shows that we trusted the data, irrespective of funding, a charge that is sometimes leveled at the Cochrane Collaboration.”
Dont expect any similar acknowledgement of mistakes or public soul-searching from the U.S. Centers for Disease Control and Prevention which was in the forefront of the enthusiasm for Tamiflu, as well as all flu vaccines. Dr. Jefferson, a long-time critic of the influential agency’s “evidence-free recommendations like flu vaccines for two-year-olds,” explains why. “The CDC is both the promoter and the evaluator of influenza drugs and vaccines…and guess what…they’re never wrong.” The agency, he continued, can’t think beyond the pharmaceutical model, he continued, citing what his research shows are the safest, most reliable methods of preventing the spread of influenza—frequent handwashing, quarantine measures, and barrier methods like wearing masks and gloves.
For more information
Click into this link for the story behind this Cochrane review and the contradictory statements about the potential benefits of Tamiflu made over the last ten years by Roche, the FDA and the drug-regulatory agencies of other countries. And click into the editorial that accompanied the review. And here’s our 2011 follow-up post on the controversey.
Maryann Napoli, Center for Medical Consumers(c)