New Analysis Challenges Tamiflu Efficacy

A new review of an important flu drug has raised questions about the medication and the entire process of systematic review.

Point out that the review of oseltamivir showed that there was no evidence of effect on hospital admissions.

A new review of the influenza drug oseltamivir (Tamiflu) has raised questions about both the efficacy of the medication and the commitment of its maker to supply enough data for claims about the drug to be evaluated by independent experts.

It also raises questions about the entire process of systematic review.

Researchers led by Tom Jefferson, MD, of the Cochrane Collaboration, pored over 15 published studies and nearly 30,000 pages of “clinical study reports.”

But, they reported, the clinical study information – data previously shared only with regulators – was only a part of what internal evidence suggested was available.

And many published studies had to be excluded because of missing or contradictory data, Jefferson and colleagues reported.

Requests for More Data
The researchers then asked the European Medicines Agency (EMA) for the data, under a Freedom of Information request, and obtained a further 25,453 pages, covering 19 trials.

But that data, too, was incomplete, they said, although the agency said it was all that was available.

The FDA is thought to have the complete reports, but has not yet responded to requests for them, the researchers reported.

Regulatory agencies such as the EMA and FDA routinely see the large clinical study reports, Jefferson and colleagues said in BMJ, but systematic reviewers and the general medical public do not.

“While regulators and systematic reviewers may assess the same clinical trials, the data they look at differs substantially,” they said.

The Cochrane group has been trying for several years to put together a clear-cut systematic review of the evidence on antivirals aimed at flu.

In 2006, the group concluded that the evidence showed that oseltamivir reduced the complications of the flu. But that conclusion was challenged on the basis that a key piece of data was flawed.

An updated review in 2009 – throwing out the flawed study — concluded there wasn’t enough evidence to show that the drug had any effect on complications.
Source :

Be the first to comment

Leave a Reply

Your email address will not be published.


18 − sixteen =