There isn't strong evidence to support stockpiling the products in national emergency drug depots in case of a pandemic, the researchers say. Both drugs—Tamiflu is the brand name for oseltamivir and Relenza is the brand name zanamivir—are designed to stop the influenza virus from spreading in an infected person, and claim to reduce the severity of flu symptoms and how long people are sick. The Centers for Disease Control and Prevention keeps the drugs in its stockpile for use in both seasonal and pandemic flu situations, and the European Medicines Agency (EMA) and the World Health Organization also recommend the medications for treating flu.
The authors of the current review found, however, that in the case of the European approvals in particular, regulatory agencies relied on summaries of studies rather than an exhaustive analysis of raw data, known as clinical study reports, which can run to more than 1,000 pages and detail methods, protocols and statistical analyses.
After a four-year effort to obtain this data from both the manufacturers and the EMA, the authors report in the journal BMJ that those trials do not support claims that the drugs lower the risk of complications from flu, such as pneumonia, or that the benefits of the drugs outweigh their risks, which include nausea, vomiting, headaches and kidney disorders.
The authors point to not just one failure in the process of approving these medications, but a weak regulatory system in which the studies are all conducted by manufacturers, and in which the trials compared the medications against placebo rather than to existing flu treatments.
Image: Woman sick with flu, via Shutterstock