Low reporting of clinical trial data in key U.S. database, study shows

The study, by Dr Andrew Prayle, Dr Matthew Hurley and Professor Alan Smyth in the University's Division of Child Health and reported in the British Medical Journal (BMJ), showed that out of the studies completed in the States during the course of 2009, less than one-quarter had logged their results on the ClinicalTrials.gov website.

Dr Prayle said: "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. The ClinicalTrials.gov 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 ClinicalTrials.gov 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."

A key principal 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. 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.

The US has lead 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 a national clinical trials registry, ClinicalTrials.gov. 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. This visionary legislation will revolutionise access to clinical trial data, as it is free for all to access.

To check compliance with the US law, the Nottingham team selected 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 per cent) had reported results. The study found that the 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. Importantly a positive effect of the legislation was noted -- where trials did not fall under the legislation only 10 per cent of them had reported results.

Dr Prayle added: "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."