clinical trials

Clinical trial results in US go unreported

U. NOTTINGHAM (UK) — Less than 25 percent of the clinical trials completed in the United States are posted in a publicly available database, despite a recent law that compels them to do so, a new study reports.

A key principle of best practice in the conduct of clinical trials is that a summary of the trial should be freely available while the study is ongoing and that, on completion of the study, the results should also be easily and quickly accessed, says Andrew Prayle, clinical research fellow at the University of Nottingham.

However, until recent times, there was no legal obligation for scientists to offer access to the results of their trial, many of which go unreported by scientific or medical journals.


“We think it’s really important that the results of clinical trials are widely disseminated to help doctors make the right decisions when treating patients,” Prayle says.

“The website allows researchers to publish summary results of clinical trials on their website, which is free for all to view. This will improve access to trial results, as not all trials end up being published in academic journals.

“Recent legislation in the USA requires some clinical trials to publish their results on the website within a year of the trial finishing. We cross-referenced the database and another database called Drugs@FDA to identify trials which should have reported results, and found that around a quarter had uploaded results to the website.”

The US has led the way in legislation to make clinical trials more transparent.  In February 2000, the Food and Drug Administration (FDA) Modernization Act in the US prompted the creation of the national clinical trials registry.

The FDA Amendments Act (FDAAA) of 2007 made it a mandatory requirement for the registration of trial result summaries within a year in most cases for studies that have at least one site in the US, are of a drug, device or biological agent, and had started or were ongoing as of September 2007.

As reported in the British Medical Journal, Prayle and colleagues checked compliance with the US law by selecting trials subject to mandatory reporting within one year which were completed between January 1 and December 31, 2009. The timeframe was chosen because all the studies completing within the year would have had at least one year to report results.

They then cross-referenced the investigational drug for each of the applicable clinical trials with the FDA database of approved drugs, Drugs@FDA. They found that out of 738 trials that were classified as subject to mandatory reporting, just 163 (22 percent) had reported results.

Influence of the funding body or sponsor seemed to be considerable—industry funded trials subject to mandatory reporting were far more likely to report results compared with other funders, the study shows.  Importantly a positive effect of the legislation was noted—where trials did not fall under the legislation only 10 percent of them had reported results, Prayle says.

“Further research is needed to identify why many trials had not had results uploaded. The legislation has only recently been enacted, and we hope that given time more clinical trials will report their results.”

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